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* [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-02 18:29 ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Borislav Petkov, Nicholas Piggin, H. Peter Anvin,
	Guo Ren, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

Background
==========

Detecting IPI *reception* is relatively easy, e.g. using
trace_irq_handler_{entry,exit} or even just function-trace
flush_smp_call_function_queue() for SMP calls.  

Figuring out their *origin*, is trickier as there is no generic tracepoint tied
to e.g. smp_call_function():

o AFAIA x86 has no tracepoint tied to sending IPIs, only receiving them
  (cf. trace_call_function{_single}_entry()).
o arm/arm64 do have trace_ipi_raise(), which gives us the target cpus but also a
  mostly useless string (smp_calls will all be "Function call interrupts").
o Other architectures don't seem to have any IPI-sending related tracepoint.  

I believe one reason those tracepoints used by arm/arm64 ended up as they were
is because these archs used to handle IPIs differently from regular interrupts
(the IRQ driver would directly invoke an IPI-handling routine), which meant they 
never showed up in trace_irq_handler_{entry, exit}. The trace_ipi_{entry,exit}
tracepoints gave a way to trace IPI reception but those have become redundant as
of: 

      56afcd3dbd19 ("ARM: Allow IPIs to be handled as normal interrupts")
      d3afc7f12987 ("arm64: Allow IPIs to be handled as normal interrupts")

which gave IPIs a "proper" handler function used through
generic_handle_domain_irq(), which makes them show up via
trace_irq_handler_{entry, exit}.

Changing stuff up
=================

Per the above, it would make sense to reshuffle trace_ipi_raise() and move it
into generic code. This also came up during Daniel's talk on Osnoise at the CPU
isolation MC of LPC 2022 [1]. 

Now, to be useful, such a tracepoint needs to export:
o targeted CPU(s)
o calling context

The only way to get the calling context with trace_ipi_raise() is to trigger a
stack dump, e.g. $(trace-cmd -e ipi* -T echo 42).

This is instead introducing a new tracepoint which exports the relevant context
(callsite, and requested callback for when the callsite isn't helpful), and is
usable by all architectures as it sits in generic code. 

Another thing worth mentioning is that depending on the callsite, the _RET_IP_
fed to the tracepoint is not always useful - generic_exec_single() doesn't tell
you much about the actual callback being sent via IPI, which is why the new
tracepoint also has a @callback argument.

Patches
=======

o Patch 1 is included for convenience and will most likely be merged
  independently. FYI I have libtraceevent patches [2] to improve the
  pretty-printing of cpumasks using the new type, which look like:
  <...>-3322  [021]   560.402583: ipi_send_cpumask:     cpumask=14,17,21 callsite=on_each_cpu_cond_mask+0x40 callback=flush_tlb_func+0x0
  <...>-187   [010]   562.590584: ipi_send_cpumask:     cpumask=0-23 callsite=on_each_cpu_cond_mask+0x40 callback=do_sync_core+0x0

o Patches 2-6 spread out the tracepoint accross relevant sites.
o Patch 8 is trying to be smart about tracing the callback associated with the
  IPI.

This results in having IPI trace events for:

o smp_call_function*()
o smp_send_reschedule()
o irq_work_queue*()
o standalone uses of __smp_call_single_queue()

This is incomplete, just looking at arm64 there's more IPI types that aren't
covered: 

  IPI_CPU_STOP,
  IPI_CPU_CRASH_STOP,
  IPI_TIMER,
  IPI_WAKEUP,

... But it feels like a good starting point.

Links
=====

[1]: https://youtu.be/5gT57y4OzBM?t=14234
[2]: https://lore.kernel.org/all/20221018151630.1513535-1-vschneid@redhat.com/

Revisions
=========

v1 -> v2
++++++++

o Ditched single-CPU tracepoint
o Changed tracepoint signature to include callback
o Changed tracepoint callsite field to void *; the parameter is still UL to save
  up on casts due to using _RET_IP_.
o Fixed linking failures due to not exporting smp_send_reschedule()

Steven Rostedt (Google) (1):
  tracing: Add __cpumask to denote a trace event field that is a
    cpumask_t

Valentin Schneider (7):
  trace: Add trace_ipi_send_cpumask()
  sched, smp: Trace IPIs sent via send_call_function_single_ipi()
  smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
  irq_work: Trace self-IPIs sent via arch_irq_work_raise()
  treewide: Trace IPIs sent via smp_send_reschedule()
  smp: reword smp call IPI comment
  sched, smp: Trace smp callback causing an IPI

 arch/alpha/kernel/smp.c                      |  2 +-
 arch/arc/kernel/smp.c                        |  2 +-
 arch/arm/kernel/smp.c                        |  5 +-
 arch/arm64/kernel/smp.c                      |  3 +-
 arch/csky/kernel/smp.c                       |  2 +-
 arch/hexagon/kernel/smp.c                    |  2 +-
 arch/ia64/kernel/smp.c                       |  4 +-
 arch/loongarch/include/asm/smp.h             |  2 +-
 arch/mips/include/asm/smp.h                  |  2 +-
 arch/openrisc/kernel/smp.c                   |  2 +-
 arch/parisc/kernel/smp.c                     |  4 +-
 arch/powerpc/kernel/smp.c                    |  4 +-
 arch/powerpc/kvm/book3s_hv.c                 |  1 +
 arch/riscv/kernel/smp.c                      |  4 +-
 arch/s390/kernel/smp.c                       |  2 +-
 arch/sh/kernel/smp.c                         |  2 +-
 arch/sparc/kernel/smp_32.c                   |  2 +-
 arch/sparc/kernel/smp_64.c                   |  2 +-
 arch/x86/include/asm/smp.h                   |  2 +-
 arch/x86/kvm/svm/svm.c                       |  1 +
 arch/x86/kvm/x86.c                           |  1 +
 arch/xtensa/kernel/smp.c                     |  2 +-
 include/linux/smp.h                          |  2 +-
 include/trace/bpf_probe.h                    |  6 ++
 include/trace/events/ipi.h                   | 22 +++++++
 include/trace/perf.h                         |  6 ++
 include/trace/stages/stage1_struct_define.h  |  6 ++
 include/trace/stages/stage2_data_offsets.h   |  6 ++
 include/trace/stages/stage3_trace_output.h   |  6 ++
 include/trace/stages/stage4_event_fields.h   |  6 ++
 include/trace/stages/stage5_get_offsets.h    |  6 ++
 include/trace/stages/stage6_event_callback.h | 20 ++++++
 include/trace/stages/stage7_class_define.h   |  2 +
 kernel/irq_work.c                            | 16 ++++-
 kernel/sched/core.c                          | 34 +++++++---
 kernel/sched/smp.h                           |  1 +
 kernel/smp.c                                 | 66 ++++++++++++++++++--
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++---
 39 files changed, 241 insertions(+), 53 deletions(-)

--
2.31.1


^ permalink raw reply	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-02 18:29 ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

Background
==========

Detecting IPI *reception* is relatively easy, e.g. using
trace_irq_handler_{entry,exit} or even just function-trace
flush_smp_call_function_queue() for SMP calls.  

Figuring out their *origin*, is trickier as there is no generic tracepoint tied
to e.g. smp_call_function():

o AFAIA x86 has no tracepoint tied to sending IPIs, only receiving them
  (cf. trace_call_function{_single}_entry()).
o arm/arm64 do have trace_ipi_raise(), which gives us the target cpus but also a
  mostly useless string (smp_calls will all be "Function call interrupts").
o Other architectures don't seem to have any IPI-sending related tracepoint.  

I believe one reason those tracepoints used by arm/arm64 ended up as they were
is because these archs used to handle IPIs differently from regular interrupts
(the IRQ driver would directly invoke an IPI-handling routine), which meant they 
never showed up in trace_irq_handler_{entry, exit}. The trace_ipi_{entry,exit}
tracepoints gave a way to trace IPI reception but those have become redundant as
of: 

      56afcd3dbd19 ("ARM: Allow IPIs to be handled as normal interrupts")
      d3afc7f12987 ("arm64: Allow IPIs to be handled as normal interrupts")

which gave IPIs a "proper" handler function used through
generic_handle_domain_irq(), which makes them show up via
trace_irq_handler_{entry, exit}.

Changing stuff up
=================

Per the above, it would make sense to reshuffle trace_ipi_raise() and move it
into generic code. This also came up during Daniel's talk on Osnoise at the CPU
isolation MC of LPC 2022 [1]. 

Now, to be useful, such a tracepoint needs to export:
o targeted CPU(s)
o calling context

The only way to get the calling context with trace_ipi_raise() is to trigger a
stack dump, e.g. $(trace-cmd -e ipi* -T echo 42).

This is instead introducing a new tracepoint which exports the relevant context
(callsite, and requested callback for when the callsite isn't helpful), and is
usable by all architectures as it sits in generic code. 

Another thing worth mentioning is that depending on the callsite, the _RET_IP_
fed to the tracepoint is not always useful - generic_exec_single() doesn't tell
you much about the actual callback being sent via IPI, which is why the new
tracepoint also has a @callback argument.

Patches
=======

o Patch 1 is included for convenience and will most likely be merged
  independently. FYI I have libtraceevent patches [2] to improve the
  pretty-printing of cpumasks using the new type, which look like:
  <...>-3322  [021]   560.402583: ipi_send_cpumask:     cpumask=14,17,21 callsite=on_each_cpu_cond_mask+0x40 callback=flush_tlb_func+0x0
  <...>-187   [010]   562.590584: ipi_send_cpumask:     cpumask=0-23 callsite=on_each_cpu_cond_mask+0x40 callback=do_sync_core+0x0

o Patches 2-6 spread out the tracepoint accross relevant sites.
o Patch 8 is trying to be smart about tracing the callback associated with the
  IPI.

This results in having IPI trace events for:

o smp_call_function*()
o smp_send_reschedule()
o irq_work_queue*()
o standalone uses of __smp_call_single_queue()

This is incomplete, just looking at arm64 there's more IPI types that aren't
covered: 

  IPI_CPU_STOP,
  IPI_CPU_CRASH_STOP,
  IPI_TIMER,
  IPI_WAKEUP,

... But it feels like a good starting point.

Links
=====

[1]: https://youtu.be/5gT57y4OzBM?t=14234
[2]: https://lore.kernel.org/all/20221018151630.1513535-1-vschneid@redhat.com/

Revisions
=========

v1 -> v2
++++++++

o Ditched single-CPU tracepoint
o Changed tracepoint signature to include callback
o Changed tracepoint callsite field to void *; the parameter is still UL to save
  up on casts due to using _RET_IP_.
o Fixed linking failures due to not exporting smp_send_reschedule()

Steven Rostedt (Google) (1):
  tracing: Add __cpumask to denote a trace event field that is a
    cpumask_t

Valentin Schneider (7):
  trace: Add trace_ipi_send_cpumask()
  sched, smp: Trace IPIs sent via send_call_function_single_ipi()
  smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
  irq_work: Trace self-IPIs sent via arch_irq_work_raise()
  treewide: Trace IPIs sent via smp_send_reschedule()
  smp: reword smp call IPI comment
  sched, smp: Trace smp callback causing an IPI

 arch/alpha/kernel/smp.c                      |  2 +-
 arch/arc/kernel/smp.c                        |  2 +-
 arch/arm/kernel/smp.c                        |  5 +-
 arch/arm64/kernel/smp.c                      |  3 +-
 arch/csky/kernel/smp.c                       |  2 +-
 arch/hexagon/kernel/smp.c                    |  2 +-
 arch/ia64/kernel/smp.c                       |  4 +-
 arch/loongarch/include/asm/smp.h             |  2 +-
 arch/mips/include/asm/smp.h                  |  2 +-
 arch/openrisc/kernel/smp.c                   |  2 +-
 arch/parisc/kernel/smp.c                     |  4 +-
 arch/powerpc/kernel/smp.c                    |  4 +-
 arch/powerpc/kvm/book3s_hv.c                 |  1 +
 arch/riscv/kernel/smp.c                      |  4 +-
 arch/s390/kernel/smp.c                       |  2 +-
 arch/sh/kernel/smp.c                         |  2 +-
 arch/sparc/kernel/smp_32.c                   |  2 +-
 arch/sparc/kernel/smp_64.c                   |  2 +-
 arch/x86/include/asm/smp.h                   |  2 +-
 arch/x86/kvm/svm/svm.c                       |  1 +
 arch/x86/kvm/x86.c                           |  1 +
 arch/xtensa/kernel/smp.c                     |  2 +-
 include/linux/smp.h                          |  2 +-
 include/trace/bpf_probe.h                    |  6 ++
 include/trace/events/ipi.h                   | 22 +++++++
 include/trace/perf.h                         |  6 ++
 include/trace/stages/stage1_struct_define.h  |  6 ++
 include/trace/stages/stage2_data_offsets.h   |  6 ++
 include/trace/stages/stage3_trace_output.h   |  6 ++
 include/trace/stages/stage4_event_fields.h   |  6 ++
 include/trace/stages/stage5_get_offsets.h    |  6 ++
 include/trace/stages/stage6_event_callback.h | 20 ++++++
 include/trace/stages/stage7_class_define.h   |  2 +
 kernel/irq_work.c                            | 16 ++++-
 kernel/sched/core.c                          | 34 +++++++---
 kernel/sched/smp.h                           |  1 +
 kernel/smp.c                                 | 66 ++++++++++++++++++--
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++---
 39 files changed, 241 insertions(+), 53 deletions(-)

--
2.31.1


^ permalink raw reply	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-02 18:29 ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

Background
==========

Detecting IPI *reception* is relatively easy, e.g. using
trace_irq_handler_{entry,exit} or even just function-trace
flush_smp_call_function_queue() for SMP calls.  

Figuring out their *origin*, is trickier as there is no generic tracepoint tied
to e.g. smp_call_function():

o AFAIA x86 has no tracepoint tied to sending IPIs, only receiving them
  (cf. trace_call_function{_single}_entry()).
o arm/arm64 do have trace_ipi_raise(), which gives us the target cpus but also a
  mostly useless string (smp_calls will all be "Function call interrupts").
o Other architectures don't seem to have any IPI-sending related tracepoint.  

I believe one reason those tracepoints used by arm/arm64 ended up as they were
is because these archs used to handle IPIs differently from regular interrupts
(the IRQ driver would directly invoke an IPI-handling routine), which meant they 
never showed up in trace_irq_handler_{entry, exit}. The trace_ipi_{entry,exit}
tracepoints gave a way to trace IPI reception but those have become redundant as
of: 

      56afcd3dbd19 ("ARM: Allow IPIs to be handled as normal interrupts")
      d3afc7f12987 ("arm64: Allow IPIs to be handled as normal interrupts")

which gave IPIs a "proper" handler function used through
generic_handle_domain_irq(), which makes them show up via
trace_irq_handler_{entry, exit}.

Changing stuff up
=================

Per the above, it would make sense to reshuffle trace_ipi_raise() and move it
into generic code. This also came up during Daniel's talk on Osnoise at the CPU
isolation MC of LPC 2022 [1]. 

Now, to be useful, such a tracepoint needs to export:
o targeted CPU(s)
o calling context

The only way to get the calling context with trace_ipi_raise() is to trigger a
stack dump, e.g. $(trace-cmd -e ipi* -T echo 42).

This is instead introducing a new tracepoint which exports the relevant context
(callsite, and requested callback for when the callsite isn't helpful), and is
usable by all architectures as it sits in generic code. 

Another thing worth mentioning is that depending on the callsite, the _RET_IP_
fed to the tracepoint is not always useful - generic_exec_single() doesn't tell
you much about the actual callback being sent via IPI, which is why the new
tracepoint also has a @callback argument.

Patches
=======

o Patch 1 is included for convenience and will most likely be merged
  independently. FYI I have libtraceevent patches [2] to improve the
  pretty-printing of cpumasks using the new type, which look like:
  <...>-3322  [021]   560.402583: ipi_send_cpumask:     cpumask=14,17,21 callsite=on_each_cpu_cond_mask+0x40 callback=flush_tlb_func+0x0
  <...>-187   [010]   562.590584: ipi_send_cpumask:     cpumask=0-23 callsite=on_each_cpu_cond_mask+0x40 callback=do_sync_core+0x0

o Patches 2-6 spread out the tracepoint accross relevant sites.
o Patch 8 is trying to be smart about tracing the callback associated with the
  IPI.

This results in having IPI trace events for:

o smp_call_function*()
o smp_send_reschedule()
o irq_work_queue*()
o standalone uses of __smp_call_single_queue()

This is incomplete, just looking at arm64 there's more IPI types that aren't
covered: 

  IPI_CPU_STOP,
  IPI_CPU_CRASH_STOP,
  IPI_TIMER,
  IPI_WAKEUP,

... But it feels like a good starting point.

Links
=====

[1]: https://youtu.be/5gT57y4OzBM?t=14234
[2]: https://lore.kernel.org/all/20221018151630.1513535-1-vschneid@redhat.com/

Revisions
=========

v1 -> v2
++++++++

o Ditched single-CPU tracepoint
o Changed tracepoint signature to include callback
o Changed tracepoint callsite field to void *; the parameter is still UL to save
  up on casts due to using _RET_IP_.
o Fixed linking failures due to not exporting smp_send_reschedule()

Steven Rostedt (Google) (1):
  tracing: Add __cpumask to denote a trace event field that is a
    cpumask_t

Valentin Schneider (7):
  trace: Add trace_ipi_send_cpumask()
  sched, smp: Trace IPIs sent via send_call_function_single_ipi()
  smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
  irq_work: Trace self-IPIs sent via arch_irq_work_raise()
  treewide: Trace IPIs sent via smp_send_reschedule()
  smp: reword smp call IPI comment
  sched, smp: Trace smp callback causing an IPI

 arch/alpha/kernel/smp.c                      |  2 +-
 arch/arc/kernel/smp.c                        |  2 +-
 arch/arm/kernel/smp.c                        |  5 +-
 arch/arm64/kernel/smp.c                      |  3 +-
 arch/csky/kernel/smp.c                       |  2 +-
 arch/hexagon/kernel/smp.c                    |  2 +-
 arch/ia64/kernel/smp.c                       |  4 +-
 arch/loongarch/include/asm/smp.h             |  2 +-
 arch/mips/include/asm/smp.h                  |  2 +-
 arch/openrisc/kernel/smp.c                   |  2 +-
 arch/parisc/kernel/smp.c                     |  4 +-
 arch/powerpc/kernel/smp.c                    |  4 +-
 arch/powerpc/kvm/book3s_hv.c                 |  1 +
 arch/riscv/kernel/smp.c                      |  4 +-
 arch/s390/kernel/smp.c                       |  2 +-
 arch/sh/kernel/smp.c                         |  2 +-
 arch/sparc/kernel/smp_32.c                   |  2 +-
 arch/sparc/kernel/smp_64.c                   |  2 +-
 arch/x86/include/asm/smp.h                   |  2 +-
 arch/x86/kvm/svm/svm.c                       |  1 +
 arch/x86/kvm/x86.c                           |  1 +
 arch/xtensa/kernel/smp.c                     |  2 +-
 include/linux/smp.h                          |  2 +-
 include/trace/bpf_probe.h                    |  6 ++
 include/trace/events/ipi.h                   | 22 +++++++
 include/trace/perf.h                         |  6 ++
 include/trace/stages/stage1_struct_define.h  |  6 ++
 include/trace/stages/stage2_data_offsets.h   |  6 ++
 include/trace/stages/stage3_trace_output.h   |  6 ++
 include/trace/stages/stage4_event_fields.h   |  6 ++
 include/trace/stages/stage5_get_offsets.h    |  6 ++
 include/trace/stages/stage6_event_callback.h | 20 ++++++
 include/trace/stages/stage7_class_define.h   |  2 +
 kernel/irq_work.c                            | 16 ++++-
 kernel/sched/core.c                          | 34 +++++++---
 kernel/sched/smp.h                           |  1 +
 kernel/smp.c                                 | 66 ++++++++++++++++++--
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++---
 39 files changed, 241 insertions(+), 53 deletions(-)

--
2.31.1


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linux-riscv@lists.infradead.org
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^ permalink raw reply	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-02 18:29 ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

Background
==========

Detecting IPI *reception* is relatively easy, e.g. using
trace_irq_handler_{entry,exit} or even just function-trace
flush_smp_call_function_queue() for SMP calls.  

Figuring out their *origin*, is trickier as there is no generic tracepoint tied
to e.g. smp_call_function():

o AFAIA x86 has no tracepoint tied to sending IPIs, only receiving them
  (cf. trace_call_function{_single}_entry()).
o arm/arm64 do have trace_ipi_raise(), which gives us the target cpus but also a
  mostly useless string (smp_calls will all be "Function call interrupts").
o Other architectures don't seem to have any IPI-sending related tracepoint.  

I believe one reason those tracepoints used by arm/arm64 ended up as they were
is because these archs used to handle IPIs differently from regular interrupts
(the IRQ driver would directly invoke an IPI-handling routine), which meant they 
never showed up in trace_irq_handler_{entry, exit}. The trace_ipi_{entry,exit}
tracepoints gave a way to trace IPI reception but those have become redundant as
of: 

      56afcd3dbd19 ("ARM: Allow IPIs to be handled as normal interrupts")
      d3afc7f12987 ("arm64: Allow IPIs to be handled as normal interrupts")

which gave IPIs a "proper" handler function used through
generic_handle_domain_irq(), which makes them show up via
trace_irq_handler_{entry, exit}.

Changing stuff up
=================

Per the above, it would make sense to reshuffle trace_ipi_raise() and move it
into generic code. This also came up during Daniel's talk on Osnoise at the CPU
isolation MC of LPC 2022 [1]. 

Now, to be useful, such a tracepoint needs to export:
o targeted CPU(s)
o calling context

The only way to get the calling context with trace_ipi_raise() is to trigger a
stack dump, e.g. $(trace-cmd -e ipi* -T echo 42).

This is instead introducing a new tracepoint which exports the relevant context
(callsite, and requested callback for when the callsite isn't helpful), and is
usable by all architectures as it sits in generic code. 

Another thing worth mentioning is that depending on the callsite, the _RET_IP_
fed to the tracepoint is not always useful - generic_exec_single() doesn't tell
you much about the actual callback being sent via IPI, which is why the new
tracepoint also has a @callback argument.

Patches
=======

o Patch 1 is included for convenience and will most likely be merged
  independently. FYI I have libtraceevent patches [2] to improve the
  pretty-printing of cpumasks using the new type, which look like:
  <...>-3322  [021]   560.402583: ipi_send_cpumask:     cpumask=14,17,21 callsite=on_each_cpu_cond_mask+0x40 callback=flush_tlb_func+0x0
  <...>-187   [010]   562.590584: ipi_send_cpumask:     cpumask=0-23 callsite=on_each_cpu_cond_mask+0x40 callback=do_sync_core+0x0

o Patches 2-6 spread out the tracepoint accross relevant sites.
o Patch 8 is trying to be smart about tracing the callback associated with the
  IPI.

This results in having IPI trace events for:

o smp_call_function*()
o smp_send_reschedule()
o irq_work_queue*()
o standalone uses of __smp_call_single_queue()

This is incomplete, just looking at arm64 there's more IPI types that aren't
covered: 

  IPI_CPU_STOP,
  IPI_CPU_CRASH_STOP,
  IPI_TIMER,
  IPI_WAKEUP,

... But it feels like a good starting point.

Links
=====

[1]: https://youtu.be/5gT57y4OzBM?t=14234
[2]: https://lore.kernel.org/all/20221018151630.1513535-1-vschneid@redhat.com/

Revisions
=========

v1 -> v2
++++++++

o Ditched single-CPU tracepoint
o Changed tracepoint signature to include callback
o Changed tracepoint callsite field to void *; the parameter is still UL to save
  up on casts due to using _RET_IP_.
o Fixed linking failures due to not exporting smp_send_reschedule()

Steven Rostedt (Google) (1):
  tracing: Add __cpumask to denote a trace event field that is a
    cpumask_t

Valentin Schneider (7):
  trace: Add trace_ipi_send_cpumask()
  sched, smp: Trace IPIs sent via send_call_function_single_ipi()
  smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
  irq_work: Trace self-IPIs sent via arch_irq_work_raise()
  treewide: Trace IPIs sent via smp_send_reschedule()
  smp: reword smp call IPI comment
  sched, smp: Trace smp callback causing an IPI

 arch/alpha/kernel/smp.c                      |  2 +-
 arch/arc/kernel/smp.c                        |  2 +-
 arch/arm/kernel/smp.c                        |  5 +-
 arch/arm64/kernel/smp.c                      |  3 +-
 arch/csky/kernel/smp.c                       |  2 +-
 arch/hexagon/kernel/smp.c                    |  2 +-
 arch/ia64/kernel/smp.c                       |  4 +-
 arch/loongarch/include/asm/smp.h             |  2 +-
 arch/mips/include/asm/smp.h                  |  2 +-
 arch/openrisc/kernel/smp.c                   |  2 +-
 arch/parisc/kernel/smp.c                     |  4 +-
 arch/powerpc/kernel/smp.c                    |  4 +-
 arch/powerpc/kvm/book3s_hv.c                 |  1 +
 arch/riscv/kernel/smp.c                      |  4 +-
 arch/s390/kernel/smp.c                       |  2 +-
 arch/sh/kernel/smp.c                         |  2 +-
 arch/sparc/kernel/smp_32.c                   |  2 +-
 arch/sparc/kernel/smp_64.c                   |  2 +-
 arch/x86/include/asm/smp.h                   |  2 +-
 arch/x86/kvm/svm/svm.c                       |  1 +
 arch/x86/kvm/x86.c                           |  1 +
 arch/xtensa/kernel/smp.c                     |  2 +-
 include/linux/smp.h                          |  2 +-
 include/trace/bpf_probe.h                    |  6 ++
 include/trace/events/ipi.h                   | 22 +++++++
 include/trace/perf.h                         |  6 ++
 include/trace/stages/stage1_struct_define.h  |  6 ++
 include/trace/stages/stage2_data_offsets.h   |  6 ++
 include/trace/stages/stage3_trace_output.h   |  6 ++
 include/trace/stages/stage4_event_fields.h   |  6 ++
 include/trace/stages/stage5_get_offsets.h    |  6 ++
 include/trace/stages/stage6_event_callback.h | 20 ++++++
 include/trace/stages/stage7_class_define.h   |  2 +
 kernel/irq_work.c                            | 16 ++++-
 kernel/sched/core.c                          | 34 +++++++---
 kernel/sched/smp.h                           |  1 +
 kernel/smp.c                                 | 66 ++++++++++++++++++--
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++---
 39 files changed, 241 insertions(+), 53 deletions(-)

--
2.31.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-02 18:29 ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

Background
==========

Detecting IPI *reception* is relatively easy, e.g. using
trace_irq_handler_{entry,exit} or even just function-trace
flush_smp_call_function_queue() for SMP calls.  

Figuring out their *origin*, is trickier as there is no generic tracepoint tied
to e.g. smp_call_function():

o AFAIA x86 has no tracepoint tied to sending IPIs, only receiving them
  (cf. trace_call_function{_single}_entry()).
o arm/arm64 do have trace_ipi_raise(), which gives us the target cpus but also a
  mostly useless string (smp_calls will all be "Function call interrupts").
o Other architectures don't seem to have any IPI-sending related tracepoint.  

I believe one reason those tracepoints used by arm/arm64 ended up as they were
is because these archs used to handle IPIs differently from regular interrupts
(the IRQ driver would directly invoke an IPI-handling routine), which meant they 
never showed up in trace_irq_handler_{entry, exit}. The trace_ipi_{entry,exit}
tracepoints gave a way to trace IPI reception but those have become redundant as
of: 

      56afcd3dbd19 ("ARM: Allow IPIs to be handled as normal interrupts")
      d3afc7f12987 ("arm64: Allow IPIs to be handled as normal interrupts")

which gave IPIs a "proper" handler function used through
generic_handle_domain_irq(), which makes them show up via
trace_irq_handler_{entry, exit}.

Changing stuff up
=================

Per the above, it would make sense to reshuffle trace_ipi_raise() and move it
into generic code. This also came up during Daniel's talk on Osnoise at the CPU
isolation MC of LPC 2022 [1]. 

Now, to be useful, such a tracepoint needs to export:
o targeted CPU(s)
o calling context

The only way to get the calling context with trace_ipi_raise() is to trigger a
stack dump, e.g. $(trace-cmd -e ipi* -T echo 42).

This is instead introducing a new tracepoint which exports the relevant context
(callsite, and requested callback for when the callsite isn't helpful), and is
usable by all architectures as it sits in generic code. 

Another thing worth mentioning is that depending on the callsite, the _RET_IP_
fed to the tracepoint is not always useful - generic_exec_single() doesn't tell
you much about the actual callback being sent via IPI, which is why the new
tracepoint also has a @callback argument.

Patches
=======

o Patch 1 is included for convenience and will most likely be merged
  independently. FYI I have libtraceevent patches [2] to improve the
  pretty-printing of cpumasks using the new type, which look like:
  <...>-3322  [021]   560.402583: ipi_send_cpumask:     cpumask=14,17,21 callsite=on_each_cpu_cond_mask+0x40 callback=flush_tlb_func+0x0
  <...>-187   [010]   562.590584: ipi_send_cpumask:     cpumask=0-23 callsite=on_each_cpu_cond_mask+0x40 callback=do_sync_core+0x0

o Patches 2-6 spread out the tracepoint accross relevant sites.
o Patch 8 is trying to be smart about tracing the callback associated with the
  IPI.

This results in having IPI trace events for:

o smp_call_function*()
o smp_send_reschedule()
o irq_work_queue*()
o standalone uses of __smp_call_single_queue()

This is incomplete, just looking at arm64 there's more IPI types that aren't
covered: 

  IPI_CPU_STOP,
  IPI_CPU_CRASH_STOP,
  IPI_TIMER,
  IPI_WAKEUP,

... But it feels like a good starting point.

Links
=====

[1]: https://youtu.be/5gT57y4OzBM?t=14234
[2]: https://lore.kernel.org/all/20221018151630.1513535-1-vschneid@redhat.com/

Revisions
=========

v1 -> v2
++++++++

o Ditched single-CPU tracepoint
o Changed tracepoint signature to include callback
o Changed tracepoint callsite field to void *; the parameter is still UL to save
  up on casts due to using _RET_IP_.
o Fixed linking failures due to not exporting smp_send_reschedule()

Steven Rostedt (Google) (1):
  tracing: Add __cpumask to denote a trace event field that is a
    cpumask_t

Valentin Schneider (7):
  trace: Add trace_ipi_send_cpumask()
  sched, smp: Trace IPIs sent via send_call_function_single_ipi()
  smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
  irq_work: Trace self-IPIs sent via arch_irq_work_raise()
  treewide: Trace IPIs sent via smp_send_reschedule()
  smp: reword smp call IPI comment
  sched, smp: Trace smp callback causing an IPI

 arch/alpha/kernel/smp.c                      |  2 +-
 arch/arc/kernel/smp.c                        |  2 +-
 arch/arm/kernel/smp.c                        |  5 +-
 arch/arm64/kernel/smp.c                      |  3 +-
 arch/csky/kernel/smp.c                       |  2 +-
 arch/hexagon/kernel/smp.c                    |  2 +-
 arch/ia64/kernel/smp.c                       |  4 +-
 arch/loongarch/include/asm/smp.h             |  2 +-
 arch/mips/include/asm/smp.h                  |  2 +-
 arch/openrisc/kernel/smp.c                   |  2 +-
 arch/parisc/kernel/smp.c                     |  4 +-
 arch/powerpc/kernel/smp.c                    |  4 +-
 arch/powerpc/kvm/book3s_hv.c                 |  1 +
 arch/riscv/kernel/smp.c                      |  4 +-
 arch/s390/kernel/smp.c                       |  2 +-
 arch/sh/kernel/smp.c                         |  2 +-
 arch/sparc/kernel/smp_32.c                   |  2 +-
 arch/sparc/kernel/smp_64.c                   |  2 +-
 arch/x86/include/asm/smp.h                   |  2 +-
 arch/x86/kvm/svm/svm.c                       |  1 +
 arch/x86/kvm/x86.c                           |  1 +
 arch/xtensa/kernel/smp.c                     |  2 +-
 include/linux/smp.h                          |  2 +-
 include/trace/bpf_probe.h                    |  6 ++
 include/trace/events/ipi.h                   | 22 +++++++
 include/trace/perf.h                         |  6 ++
 include/trace/stages/stage1_struct_define.h  |  6 ++
 include/trace/stages/stage2_data_offsets.h   |  6 ++
 include/trace/stages/stage3_trace_output.h   |  6 ++
 include/trace/stages/stage4_event_fields.h   |  6 ++
 include/trace/stages/stage5_get_offsets.h    |  6 ++
 include/trace/stages/stage6_event_callback.h | 20 ++++++
 include/trace/stages/stage7_class_define.h   |  2 +
 kernel/irq_work.c                            | 16 ++++-
 kernel/sched/core.c                          | 34 +++++++---
 kernel/sched/smp.h                           |  1 +
 kernel/smp.c                                 | 66 ++++++++++++++++++--
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++---
 39 files changed, 241 insertions(+), 53 deletions(-)

--
2.31.1


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-02 18:29 ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Borislav Petkov, Nicholas Piggin, H. Peter Anvin,
	Guo Ren, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

Background
=====

Detecting IPI *reception* is relatively easy, e.g. using
trace_irq_handler_{entry,exit} or even just function-trace
flush_smp_call_function_queue() for SMP calls.  

Figuring out their *origin*, is trickier as there is no generic tracepoint tied
to e.g. smp_call_function():

o AFAIA x86 has no tracepoint tied to sending IPIs, only receiving them
  (cf. trace_call_function{_single}_entry()).
o arm/arm64 do have trace_ipi_raise(), which gives us the target cpus but also a
  mostly useless string (smp_calls will all be "Function call interrupts").
o Other architectures don't seem to have any IPI-sending related tracepoint.  

I believe one reason those tracepoints used by arm/arm64 ended up as they were
is because these archs used to handle IPIs differently from regular interrupts
(the IRQ driver would directly invoke an IPI-handling routine), which meant they 
never showed up in trace_irq_handler_{entry, exit}. The trace_ipi_{entry,exit}
tracepoints gave a way to trace IPI reception but those have become redundant as
of: 

      56afcd3dbd19 ("ARM: Allow IPIs to be handled as normal interrupts")
      d3afc7f12987 ("arm64: Allow IPIs to be handled as normal interrupts")

which gave IPIs a "proper" handler function used through
generic_handle_domain_irq(), which makes them show up via
trace_irq_handler_{entry, exit}.

Changing stuff up
========
Per the above, it would make sense to reshuffle trace_ipi_raise() and move it
into generic code. This also came up during Daniel's talk on Osnoise at the CPU
isolation MC of LPC 2022 [1]. 

Now, to be useful, such a tracepoint needs to export:
o targeted CPU(s)
o calling context

The only way to get the calling context with trace_ipi_raise() is to trigger a
stack dump, e.g. $(trace-cmd -e ipi* -T echo 42).

This is instead introducing a new tracepoint which exports the relevant context
(callsite, and requested callback for when the callsite isn't helpful), and is
usable by all architectures as it sits in generic code. 

Another thing worth mentioning is that depending on the callsite, the _RET_IP_
fed to the tracepoint is not always useful - generic_exec_single() doesn't tell
you much about the actual callback being sent via IPI, which is why the new
tracepoint also has a @callback argument.

Patches
===
o Patch 1 is included for convenience and will most likely be merged
  independently. FYI I have libtraceevent patches [2] to improve the
  pretty-printing of cpumasks using the new type, which look like:
  <...>-3322  [021]   560.402583: ipi_send_cpumask:     cpumask\x14,17,21 callsite=on_each_cpu_cond_mask+0x40 callback=flush_tlb_func+0x0
  <...>-187   [010]   562.590584: ipi_send_cpumask:     cpumask=0-23 callsite=on_each_cpu_cond_mask+0x40 callback=do_sync_core+0x0

o Patches 2-6 spread out the tracepoint accross relevant sites.
o Patch 8 is trying to be smart about tracing the callback associated with the
  IPI.

This results in having IPI trace events for:

o smp_call_function*()
o smp_send_reschedule()
o irq_work_queue*()
o standalone uses of __smp_call_single_queue()

This is incomplete, just looking at arm64 there's more IPI types that aren't
covered: 

  IPI_CPU_STOP,
  IPI_CPU_CRASH_STOP,
  IPI_TIMER,
  IPI_WAKEUP,

... But it feels like a good starting point.

Links
==
[1]: https://youtu.be/5gT57y4OzBM?t\x14234
[2]: https://lore.kernel.org/all/20221018151630.1513535-1-vschneid@redhat.com/

Revisions
====
v1 -> v2
++++++++

o Ditched single-CPU tracepoint
o Changed tracepoint signature to include callback
o Changed tracepoint callsite field to void *; the parameter is still UL to save
  up on casts due to using _RET_IP_.
o Fixed linking failures due to not exporting smp_send_reschedule()

Steven Rostedt (Google) (1):
  tracing: Add __cpumask to denote a trace event field that is a
    cpumask_t

Valentin Schneider (7):
  trace: Add trace_ipi_send_cpumask()
  sched, smp: Trace IPIs sent via send_call_function_single_ipi()
  smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
  irq_work: Trace self-IPIs sent via arch_irq_work_raise()
  treewide: Trace IPIs sent via smp_send_reschedule()
  smp: reword smp call IPI comment
  sched, smp: Trace smp callback causing an IPI

 arch/alpha/kernel/smp.c                      |  2 +-
 arch/arc/kernel/smp.c                        |  2 +-
 arch/arm/kernel/smp.c                        |  5 +-
 arch/arm64/kernel/smp.c                      |  3 +-
 arch/csky/kernel/smp.c                       |  2 +-
 arch/hexagon/kernel/smp.c                    |  2 +-
 arch/ia64/kernel/smp.c                       |  4 +-
 arch/loongarch/include/asm/smp.h             |  2 +-
 arch/mips/include/asm/smp.h                  |  2 +-
 arch/openrisc/kernel/smp.c                   |  2 +-
 arch/parisc/kernel/smp.c                     |  4 +-
 arch/powerpc/kernel/smp.c                    |  4 +-
 arch/powerpc/kvm/book3s_hv.c                 |  1 +
 arch/riscv/kernel/smp.c                      |  4 +-
 arch/s390/kernel/smp.c                       |  2 +-
 arch/sh/kernel/smp.c                         |  2 +-
 arch/sparc/kernel/smp_32.c                   |  2 +-
 arch/sparc/kernel/smp_64.c                   |  2 +-
 arch/x86/include/asm/smp.h                   |  2 +-
 arch/x86/kvm/svm/svm.c                       |  1 +
 arch/x86/kvm/x86.c                           |  1 +
 arch/xtensa/kernel/smp.c                     |  2 +-
 include/linux/smp.h                          |  2 +-
 include/trace/bpf_probe.h                    |  6 ++
 include/trace/events/ipi.h                   | 22 +++++++
 include/trace/perf.h                         |  6 ++
 include/trace/stages/stage1_struct_define.h  |  6 ++
 include/trace/stages/stage2_data_offsets.h   |  6 ++
 include/trace/stages/stage3_trace_output.h   |  6 ++
 include/trace/stages/stage4_event_fields.h   |  6 ++
 include/trace/stages/stage5_get_offsets.h    |  6 ++
 include/trace/stages/stage6_event_callback.h | 20 ++++++
 include/trace/stages/stage7_class_define.h   |  2 +
 kernel/irq_work.c                            | 16 ++++-
 kernel/sched/core.c                          | 34 +++++++---
 kernel/sched/smp.h                           |  1 +
 kernel/smp.c                                 | 66 ++++++++++++++++++--
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++---
 39 files changed, 241 insertions(+), 53 deletions(-)

--
2.31.1

^ permalink raw reply	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 1/8] DO-NOT-MERGE: tracing: Add __cpumask to denote a trace event field that is a cpumask_t
  2022-11-02 18:29 ` Valentin Schneider
                     ` (3 preceding siblings ...)
  (?)
@ 2022-11-02 18:29   ` Valentin Schneider
  -1 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt (Google),
	David S. Miller, Ingo Molnar, Borislav Petkov, Nicholas Piggin,
	H. Peter Anvin, Guo Ren, Thomas Gleixner,
	Daniel Bristot de Oliveira, Frederic Weisbecker

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

The trace events have a __bitmask field that can be used for anything
that requires bitmasks. Although currently it is only used for CPU
masks, it could be used in the future for any type of bitmasks.

There is some user space tooling that wants to know if a field is a CPU
mask and not just some random unsigned long bitmask. Introduce
"__cpumask()" helper functions that work the same as the current
__bitmask() helpers but displays in the format file:

  field:__data_loc cpumask_t *[] mask;    offset:36;      size:4; signed:0;

Instead of:

  field:__data_loc unsigned long[] mask;  offset:32;      size:4; signed:0;

The main difference is the type. Instead of "unsigned long" it is
"cpumask_t *". Note, this type field needs to be a real type in the
__dynamic_array() logic that both __cpumask and__bitmask use, but the
comparison field requires it to be a scalar type whereas cpumask_t is a
structure (non-scalar). But everything works when making it a pointer.

Valentin added changes to remove the need of passing in "nr_bits" and the
__cpumask will always use nr_cpumask_bits as its size.

Requested-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/trace/bpf_probe.h                    |  6 ++++
 include/trace/perf.h                         |  6 ++++
 include/trace/stages/stage1_struct_define.h  |  6 ++++
 include/trace/stages/stage2_data_offsets.h   |  6 ++++
 include/trace/stages/stage3_trace_output.h   |  6 ++++
 include/trace/stages/stage4_event_fields.h   |  6 ++++
 include/trace/stages/stage5_get_offsets.h    |  6 ++++
 include/trace/stages/stage6_event_callback.h | 20 ++++++++++++
 include/trace/stages/stage7_class_define.h   |  2 ++
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++++++++++-----
 11 files changed, 91 insertions(+), 9 deletions(-)

diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h
index 6a13220d2d27b..155c495b89ead 100644
--- a/include/trace/bpf_probe.h
+++ b/include/trace/bpf_probe.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -40,6 +43,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/perf.h b/include/trace/perf.h
index 5800d13146c3d..8f3bf1e177070 100644
--- a/include/trace/perf.h
+++ b/include/trace/perf.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -41,6 +44,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/stages/stage1_struct_define.h b/include/trace/stages/stage1_struct_define.h
index 1b7bab60434c1..69e0dae453bfa 100644
--- a/include/trace/stages/stage1_struct_define.h
+++ b/include/trace/stages/stage1_struct_define.h
@@ -32,6 +32,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(char, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(char, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -47,6 +50,9 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(char, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(char, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage2_data_offsets.h b/include/trace/stages/stage2_data_offsets.h
index 1b7a8f764fddd..469b6a64293de 100644
--- a/include/trace/stages/stage2_data_offsets.h
+++ b/include/trace/stages/stage2_data_offsets.h
@@ -38,6 +38,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -53,5 +56,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage3_trace_output.h b/include/trace/stages/stage3_trace_output.h
index e3b183e9d18ea..66374df61ed30 100644
--- a/include/trace/stages/stage3_trace_output.h
+++ b/include/trace/stages/stage3_trace_output.h
@@ -42,6 +42,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_cpumask
+#define __get_cpumask(field) __get_bitmask(field)
+
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field)						\
	({								\
@@ -51,6 +54,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) __get_rel_bitmask(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field)	((struct sockaddr *)__get_dynamic_array(field))

diff --git a/include/trace/stages/stage4_event_fields.h b/include/trace/stages/stage4_event_fields.h
index a8fb25f39a99d..f2990d22313cf 100644
--- a/include/trace/stages/stage4_event_fields.h
+++ b/include/trace/stages/stage4_event_fields.h
@@ -46,6 +46,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(cpumask_t *, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -64,5 +67,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(cpumask_t *, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage5_get_offsets.h b/include/trace/stages/stage5_get_offsets.h
index fba4c24ed9e60..ac5c24d3beeb2 100644
--- a/include/trace/stages/stage5_get_offsets.h
+++ b/include/trace/stages/stage5_get_offsets.h
@@ -82,10 +82,16 @@
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __bitmask(item, nr_cpumask_bits)
+
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_bitmask(item, nr_cpumask_bits)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage6_event_callback.h b/include/trace/stages/stage6_event_callback.h
index 3c554a5853204..49c32394b53fb 100644
--- a/include/trace/stages/stage6_event_callback.h
+++ b/include/trace/stages/stage6_event_callback.h
@@ -57,6 +57,16 @@
 #define __assign_bitmask(dst, src, nr_bits)					\
	memcpy(__get_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
+#undef __assign_cpumask
+#define __assign_cpumask(dst, src)					\
+	memcpy(__get_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -98,6 +108,16 @@
 #define __assign_rel_bitmask(dst, src, nr_bits)					\
	memcpy(__get_rel_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
+#undef __assign_rel_cpumask
+#define __assign_rel_cpumask(dst, src)					\
+	memcpy(__get_rel_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage7_class_define.h b/include/trace/stages/stage7_class_define.h
index 8a7ec24c246dd..8795429f388b0 100644
--- a/include/trace/stages/stage7_class_define.h
+++ b/include/trace/stages/stage7_class_define.h
@@ -13,11 +13,13 @@
 #undef __get_dynamic_array_len
 #undef __get_str
 #undef __get_bitmask
+#undef __get_cpumask
 #undef __get_sockaddr
 #undef __get_rel_dynamic_array
 #undef __get_rel_dynamic_array_len
 #undef __get_rel_str
 #undef __get_rel_bitmask
+#undef __get_rel_cpumask
 #undef __get_rel_sockaddr
 #undef __print_array
 #undef __print_hex_dump
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index 608c4ae3b08a3..ecc7db237f2ef 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -50,7 +50,7 @@ static void do_simple_thread_func(int cnt, const char *fmt, ...)

	trace_foo_with_template_print("I have to be different", cnt);

-	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask);
+	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask, current->cpus_ptr);
 }

 static void simple_thread_func(int cnt)
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 1a92226202fc5..fb4548a44153c 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -200,6 +200,16 @@
  *
  *         __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits);
  *
+ *   __cpumask: This is pretty much the same as __bitmask but is specific for
+ *         CPU masks. The type displayed to the user via the format files will
+ *         be "cpumaks_t" such that user space may deal with them differently
+ *         if they choose to do so, and the bits is always set to nr_cpumask_bits.
+ *
+ *         __cpumask(target_cpu)
+ *
+ *         To assign a cpumask, use the __assign_cpumask() helper macro.
+ *
+ *         __assign_cpumask(target_cpus, cpumask_bits(bar));
  *
  * fast_assign: This is a C like function that is used to store the items
  *    into the ring buffer. A special variable called "__entry" will be the
@@ -212,8 +222,8 @@
  *    This is also used to print out the data from the trace files.
  *    Again, the __entry macro is used to access the data from the ring buffer.
  *
- *    Note, __dynamic_array, __string, and __bitmask require special helpers
- *       to access the data.
+ *    Note, __dynamic_array, __string, __bitmask and __cpumask require special
+ *       helpers to access the data.
  *
  *      For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo)
  *            Use __get_dynamic_array_len(foo) to get the length of the array
@@ -226,6 +236,8 @@
  *
  *      For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus)
  *
+ *      For __cpumask(target_cpus) use __get_cpumask(target_cpus)
+ *
  *
  * Note, that for both the assign and the printk, __entry is the handler
  * to the data structure in the ring buffer, and is defined by the
@@ -288,6 +300,7 @@ TRACE_EVENT(foo_bar,
		__dynamic_array(int,	list,   __length_of(lst))
		__string(	str,	string			)
		__bitmask(	cpus,	num_possible_cpus()	)
+		__cpumask(	cpum				)
		__vstring(	vstr,	fmt,	va		)
	),

@@ -299,9 +312,10 @@ TRACE_EVENT(foo_bar,
		__assign_str(str, string);
		__assign_vstr(vstr, fmt, va);
		__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
+		__assign_cpumask(cpum, cpumask_bits(mask));
	),

-	TP_printk("foo %s %d %s %s %s %s (%s) %s", __entry->foo, __entry->bar,
+	TP_printk("foo %s %d %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,

 /*
  * Notice here the use of some helper functions. This includes:
@@ -345,7 +359,8 @@ TRACE_EVENT(foo_bar,
		  __print_array(__get_dynamic_array(list),
				__get_dynamic_array_len(list) / sizeof(int),
				sizeof(int)),
-		  __get_str(str), __get_bitmask(cpus), __get_str(vstr))
+		  __get_str(str), __get_bitmask(cpus), __get_cpumask(cpus),
+		  __get_str(vstr))
 );

 /*
@@ -542,15 +557,16 @@ DEFINE_EVENT_PRINT(foo_template, foo_with_template_print,

 TRACE_EVENT(foo_rel_loc,

-	TP_PROTO(const char *foo, int bar, unsigned long *mask),
+	TP_PROTO(const char *foo, int bar, unsigned long *mask, const cpumask_t *cpus),

-	TP_ARGS(foo, bar, mask),
+	TP_ARGS(foo, bar, mask, cpus),

	TP_STRUCT__entry(
		__rel_string(	foo,	foo	)
		__field(	int,	bar	)
		__rel_bitmask(	bitmask,
			BITS_PER_BYTE * sizeof(unsigned long)	)
+		__rel_cpumask(	cpumask )
	),

	TP_fast_assign(
@@ -558,10 +574,12 @@ TRACE_EVENT(foo_rel_loc,
		__entry->bar = bar;
		__assign_rel_bitmask(bitmask, mask,
			BITS_PER_BYTE * sizeof(unsigned long));
+		__assign_rel_cpumask(cpumask, cpus);
	),

-	TP_printk("foo_rel_loc %s, %d, %s", __get_rel_str(foo), __entry->bar,
-		  __get_rel_bitmask(bitmask))
+	TP_printk("foo_rel_loc %s, %d, %s, %s", __get_rel_str(foo), __entry->bar,
+		  __get_rel_bitmask(bitmask),
+		  __get_rel_cpumask(cpumask))
 );
 #endif

--
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 1/8] DO-NOT-MERGE: tracing: Add __cpumask to denote a trace event field that is a cpumask_t
@ 2022-11-02 18:29   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Steven Rostedt (Google),
	Paul E. McKenney, Peter Zijlstra, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

The trace events have a __bitmask field that can be used for anything
that requires bitmasks. Although currently it is only used for CPU
masks, it could be used in the future for any type of bitmasks.

There is some user space tooling that wants to know if a field is a CPU
mask and not just some random unsigned long bitmask. Introduce
"__cpumask()" helper functions that work the same as the current
__bitmask() helpers but displays in the format file:

  field:__data_loc cpumask_t *[] mask;    offset:36;      size:4; signed:0;

Instead of:

  field:__data_loc unsigned long[] mask;  offset:32;      size:4; signed:0;

The main difference is the type. Instead of "unsigned long" it is
"cpumask_t *". Note, this type field needs to be a real type in the
__dynamic_array() logic that both __cpumask and__bitmask use, but the
comparison field requires it to be a scalar type whereas cpumask_t is a
structure (non-scalar). But everything works when making it a pointer.

Valentin added changes to remove the need of passing in "nr_bits" and the
__cpumask will always use nr_cpumask_bits as its size.

Requested-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/trace/bpf_probe.h                    |  6 ++++
 include/trace/perf.h                         |  6 ++++
 include/trace/stages/stage1_struct_define.h  |  6 ++++
 include/trace/stages/stage2_data_offsets.h   |  6 ++++
 include/trace/stages/stage3_trace_output.h   |  6 ++++
 include/trace/stages/stage4_event_fields.h   |  6 ++++
 include/trace/stages/stage5_get_offsets.h    |  6 ++++
 include/trace/stages/stage6_event_callback.h | 20 ++++++++++++
 include/trace/stages/stage7_class_define.h   |  2 ++
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++++++++++-----
 11 files changed, 91 insertions(+), 9 deletions(-)

diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h
index 6a13220d2d27b..155c495b89ead 100644
--- a/include/trace/bpf_probe.h
+++ b/include/trace/bpf_probe.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -40,6 +43,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/perf.h b/include/trace/perf.h
index 5800d13146c3d..8f3bf1e177070 100644
--- a/include/trace/perf.h
+++ b/include/trace/perf.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -41,6 +44,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/stages/stage1_struct_define.h b/include/trace/stages/stage1_struct_define.h
index 1b7bab60434c1..69e0dae453bfa 100644
--- a/include/trace/stages/stage1_struct_define.h
+++ b/include/trace/stages/stage1_struct_define.h
@@ -32,6 +32,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(char, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(char, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -47,6 +50,9 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(char, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(char, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage2_data_offsets.h b/include/trace/stages/stage2_data_offsets.h
index 1b7a8f764fddd..469b6a64293de 100644
--- a/include/trace/stages/stage2_data_offsets.h
+++ b/include/trace/stages/stage2_data_offsets.h
@@ -38,6 +38,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -53,5 +56,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage3_trace_output.h b/include/trace/stages/stage3_trace_output.h
index e3b183e9d18ea..66374df61ed30 100644
--- a/include/trace/stages/stage3_trace_output.h
+++ b/include/trace/stages/stage3_trace_output.h
@@ -42,6 +42,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_cpumask
+#define __get_cpumask(field) __get_bitmask(field)
+
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field)						\
	({								\
@@ -51,6 +54,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) __get_rel_bitmask(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field)	((struct sockaddr *)__get_dynamic_array(field))

diff --git a/include/trace/stages/stage4_event_fields.h b/include/trace/stages/stage4_event_fields.h
index a8fb25f39a99d..f2990d22313cf 100644
--- a/include/trace/stages/stage4_event_fields.h
+++ b/include/trace/stages/stage4_event_fields.h
@@ -46,6 +46,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(cpumask_t *, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -64,5 +67,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(cpumask_t *, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage5_get_offsets.h b/include/trace/stages/stage5_get_offsets.h
index fba4c24ed9e60..ac5c24d3beeb2 100644
--- a/include/trace/stages/stage5_get_offsets.h
+++ b/include/trace/stages/stage5_get_offsets.h
@@ -82,10 +82,16 @@
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __bitmask(item, nr_cpumask_bits)
+
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_bitmask(item, nr_cpumask_bits)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage6_event_callback.h b/include/trace/stages/stage6_event_callback.h
index 3c554a5853204..49c32394b53fb 100644
--- a/include/trace/stages/stage6_event_callback.h
+++ b/include/trace/stages/stage6_event_callback.h
@@ -57,6 +57,16 @@
 #define __assign_bitmask(dst, src, nr_bits)					\
	memcpy(__get_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
+#undef __assign_cpumask
+#define __assign_cpumask(dst, src)					\
+	memcpy(__get_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -98,6 +108,16 @@
 #define __assign_rel_bitmask(dst, src, nr_bits)					\
	memcpy(__get_rel_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
+#undef __assign_rel_cpumask
+#define __assign_rel_cpumask(dst, src)					\
+	memcpy(__get_rel_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage7_class_define.h b/include/trace/stages/stage7_class_define.h
index 8a7ec24c246dd..8795429f388b0 100644
--- a/include/trace/stages/stage7_class_define.h
+++ b/include/trace/stages/stage7_class_define.h
@@ -13,11 +13,13 @@
 #undef __get_dynamic_array_len
 #undef __get_str
 #undef __get_bitmask
+#undef __get_cpumask
 #undef __get_sockaddr
 #undef __get_rel_dynamic_array
 #undef __get_rel_dynamic_array_len
 #undef __get_rel_str
 #undef __get_rel_bitmask
+#undef __get_rel_cpumask
 #undef __get_rel_sockaddr
 #undef __print_array
 #undef __print_hex_dump
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index 608c4ae3b08a3..ecc7db237f2ef 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -50,7 +50,7 @@ static void do_simple_thread_func(int cnt, const char *fmt, ...)

	trace_foo_with_template_print("I have to be different", cnt);

-	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask);
+	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask, current->cpus_ptr);
 }

 static void simple_thread_func(int cnt)
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 1a92226202fc5..fb4548a44153c 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -200,6 +200,16 @@
  *
  *         __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits);
  *
+ *   __cpumask: This is pretty much the same as __bitmask but is specific for
+ *         CPU masks. The type displayed to the user via the format files will
+ *         be "cpumaks_t" such that user space may deal with them differently
+ *         if they choose to do so, and the bits is always set to nr_cpumask_bits.
+ *
+ *         __cpumask(target_cpu)
+ *
+ *         To assign a cpumask, use the __assign_cpumask() helper macro.
+ *
+ *         __assign_cpumask(target_cpus, cpumask_bits(bar));
  *
  * fast_assign: This is a C like function that is used to store the items
  *    into the ring buffer. A special variable called "__entry" will be the
@@ -212,8 +222,8 @@
  *    This is also used to print out the data from the trace files.
  *    Again, the __entry macro is used to access the data from the ring buffer.
  *
- *    Note, __dynamic_array, __string, and __bitmask require special helpers
- *       to access the data.
+ *    Note, __dynamic_array, __string, __bitmask and __cpumask require special
+ *       helpers to access the data.
  *
  *      For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo)
  *            Use __get_dynamic_array_len(foo) to get the length of the array
@@ -226,6 +236,8 @@
  *
  *      For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus)
  *
+ *      For __cpumask(target_cpus) use __get_cpumask(target_cpus)
+ *
  *
  * Note, that for both the assign and the printk, __entry is the handler
  * to the data structure in the ring buffer, and is defined by the
@@ -288,6 +300,7 @@ TRACE_EVENT(foo_bar,
		__dynamic_array(int,	list,   __length_of(lst))
		__string(	str,	string			)
		__bitmask(	cpus,	num_possible_cpus()	)
+		__cpumask(	cpum				)
		__vstring(	vstr,	fmt,	va		)
	),

@@ -299,9 +312,10 @@ TRACE_EVENT(foo_bar,
		__assign_str(str, string);
		__assign_vstr(vstr, fmt, va);
		__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
+		__assign_cpumask(cpum, cpumask_bits(mask));
	),

-	TP_printk("foo %s %d %s %s %s %s (%s) %s", __entry->foo, __entry->bar,
+	TP_printk("foo %s %d %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,

 /*
  * Notice here the use of some helper functions. This includes:
@@ -345,7 +359,8 @@ TRACE_EVENT(foo_bar,
		  __print_array(__get_dynamic_array(list),
				__get_dynamic_array_len(list) / sizeof(int),
				sizeof(int)),
-		  __get_str(str), __get_bitmask(cpus), __get_str(vstr))
+		  __get_str(str), __get_bitmask(cpus), __get_cpumask(cpus),
+		  __get_str(vstr))
 );

 /*
@@ -542,15 +557,16 @@ DEFINE_EVENT_PRINT(foo_template, foo_with_template_print,

 TRACE_EVENT(foo_rel_loc,

-	TP_PROTO(const char *foo, int bar, unsigned long *mask),
+	TP_PROTO(const char *foo, int bar, unsigned long *mask, const cpumask_t *cpus),

-	TP_ARGS(foo, bar, mask),
+	TP_ARGS(foo, bar, mask, cpus),

	TP_STRUCT__entry(
		__rel_string(	foo,	foo	)
		__field(	int,	bar	)
		__rel_bitmask(	bitmask,
			BITS_PER_BYTE * sizeof(unsigned long)	)
+		__rel_cpumask(	cpumask )
	),

	TP_fast_assign(
@@ -558,10 +574,12 @@ TRACE_EVENT(foo_rel_loc,
		__entry->bar = bar;
		__assign_rel_bitmask(bitmask, mask,
			BITS_PER_BYTE * sizeof(unsigned long));
+		__assign_rel_cpumask(cpumask, cpus);
	),

-	TP_printk("foo_rel_loc %s, %d, %s", __get_rel_str(foo), __entry->bar,
-		  __get_rel_bitmask(bitmask))
+	TP_printk("foo_rel_loc %s, %d, %s, %s", __get_rel_str(foo), __entry->bar,
+		  __get_rel_bitmask(bitmask),
+		  __get_rel_cpumask(cpumask))
 );
 #endif

--
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 1/8] DO-NOT-MERGE: tracing: Add __cpumask to denote a trace event field that is a cpumask_t
@ 2022-11-02 18:29   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Steven Rostedt (Google),
	Paul E. McKenney, Peter Zijlstra, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

The trace events have a __bitmask field that can be used for anything
that requires bitmasks. Although currently it is only used for CPU
masks, it could be used in the future for any type of bitmasks.

There is some user space tooling that wants to know if a field is a CPU
mask and not just some random unsigned long bitmask. Introduce
"__cpumask()" helper functions that work the same as the current
__bitmask() helpers but displays in the format file:

  field:__data_loc cpumask_t *[] mask;    offset:36;      size:4; signed:0;

Instead of:

  field:__data_loc unsigned long[] mask;  offset:32;      size:4; signed:0;

The main difference is the type. Instead of "unsigned long" it is
"cpumask_t *". Note, this type field needs to be a real type in the
__dynamic_array() logic that both __cpumask and__bitmask use, but the
comparison field requires it to be a scalar type whereas cpumask_t is a
structure (non-scalar). But everything works when making it a pointer.

Valentin added changes to remove the need of passing in "nr_bits" and the
__cpumask will always use nr_cpumask_bits as its size.

Requested-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/trace/bpf_probe.h                    |  6 ++++
 include/trace/perf.h                         |  6 ++++
 include/trace/stages/stage1_struct_define.h  |  6 ++++
 include/trace/stages/stage2_data_offsets.h   |  6 ++++
 include/trace/stages/stage3_trace_output.h   |  6 ++++
 include/trace/stages/stage4_event_fields.h   |  6 ++++
 include/trace/stages/stage5_get_offsets.h    |  6 ++++
 include/trace/stages/stage6_event_callback.h | 20 ++++++++++++
 include/trace/stages/stage7_class_define.h   |  2 ++
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++++++++++-----
 11 files changed, 91 insertions(+), 9 deletions(-)

diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h
index 6a13220d2d27b..155c495b89ead 100644
--- a/include/trace/bpf_probe.h
+++ b/include/trace/bpf_probe.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -40,6 +43,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/perf.h b/include/trace/perf.h
index 5800d13146c3d..8f3bf1e177070 100644
--- a/include/trace/perf.h
+++ b/include/trace/perf.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -41,6 +44,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/stages/stage1_struct_define.h b/include/trace/stages/stage1_struct_define.h
index 1b7bab60434c1..69e0dae453bfa 100644
--- a/include/trace/stages/stage1_struct_define.h
+++ b/include/trace/stages/stage1_struct_define.h
@@ -32,6 +32,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(char, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(char, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -47,6 +50,9 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(char, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(char, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage2_data_offsets.h b/include/trace/stages/stage2_data_offsets.h
index 1b7a8f764fddd..469b6a64293de 100644
--- a/include/trace/stages/stage2_data_offsets.h
+++ b/include/trace/stages/stage2_data_offsets.h
@@ -38,6 +38,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -53,5 +56,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage3_trace_output.h b/include/trace/stages/stage3_trace_output.h
index e3b183e9d18ea..66374df61ed30 100644
--- a/include/trace/stages/stage3_trace_output.h
+++ b/include/trace/stages/stage3_trace_output.h
@@ -42,6 +42,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_cpumask
+#define __get_cpumask(field) __get_bitmask(field)
+
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field)						\
	({								\
@@ -51,6 +54,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) __get_rel_bitmask(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field)	((struct sockaddr *)__get_dynamic_array(field))

diff --git a/include/trace/stages/stage4_event_fields.h b/include/trace/stages/stage4_event_fields.h
index a8fb25f39a99d..f2990d22313cf 100644
--- a/include/trace/stages/stage4_event_fields.h
+++ b/include/trace/stages/stage4_event_fields.h
@@ -46,6 +46,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(cpumask_t *, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -64,5 +67,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(cpumask_t *, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage5_get_offsets.h b/include/trace/stages/stage5_get_offsets.h
index fba4c24ed9e60..ac5c24d3beeb2 100644
--- a/include/trace/stages/stage5_get_offsets.h
+++ b/include/trace/stages/stage5_get_offsets.h
@@ -82,10 +82,16 @@
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __bitmask(item, nr_cpumask_bits)
+
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_bitmask(item, nr_cpumask_bits)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage6_event_callback.h b/include/trace/stages/stage6_event_callback.h
index 3c554a5853204..49c32394b53fb 100644
--- a/include/trace/stages/stage6_event_callback.h
+++ b/include/trace/stages/stage6_event_callback.h
@@ -57,6 +57,16 @@
 #define __assign_bitmask(dst, src, nr_bits)					\
	memcpy(__get_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
+#undef __assign_cpumask
+#define __assign_cpumask(dst, src)					\
+	memcpy(__get_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -98,6 +108,16 @@
 #define __assign_rel_bitmask(dst, src, nr_bits)					\
	memcpy(__get_rel_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
+#undef __assign_rel_cpumask
+#define __assign_rel_cpumask(dst, src)					\
+	memcpy(__get_rel_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage7_class_define.h b/include/trace/stages/stage7_class_define.h
index 8a7ec24c246dd..8795429f388b0 100644
--- a/include/trace/stages/stage7_class_define.h
+++ b/include/trace/stages/stage7_class_define.h
@@ -13,11 +13,13 @@
 #undef __get_dynamic_array_len
 #undef __get_str
 #undef __get_bitmask
+#undef __get_cpumask
 #undef __get_sockaddr
 #undef __get_rel_dynamic_array
 #undef __get_rel_dynamic_array_len
 #undef __get_rel_str
 #undef __get_rel_bitmask
+#undef __get_rel_cpumask
 #undef __get_rel_sockaddr
 #undef __print_array
 #undef __print_hex_dump
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index 608c4ae3b08a3..ecc7db237f2ef 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -50,7 +50,7 @@ static void do_simple_thread_func(int cnt, const char *fmt, ...)

	trace_foo_with_template_print("I have to be different", cnt);

-	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask);
+	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask, current->cpus_ptr);
 }

 static void simple_thread_func(int cnt)
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 1a92226202fc5..fb4548a44153c 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -200,6 +200,16 @@
  *
  *         __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits);
  *
+ *   __cpumask: This is pretty much the same as __bitmask but is specific for
+ *         CPU masks. The type displayed to the user via the format files will
+ *         be "cpumaks_t" such that user space may deal with them differently
+ *         if they choose to do so, and the bits is always set to nr_cpumask_bits.
+ *
+ *         __cpumask(target_cpu)
+ *
+ *         To assign a cpumask, use the __assign_cpumask() helper macro.
+ *
+ *         __assign_cpumask(target_cpus, cpumask_bits(bar));
  *
  * fast_assign: This is a C like function that is used to store the items
  *    into the ring buffer. A special variable called "__entry" will be the
@@ -212,8 +222,8 @@
  *    This is also used to print out the data from the trace files.
  *    Again, the __entry macro is used to access the data from the ring buffer.
  *
- *    Note, __dynamic_array, __string, and __bitmask require special helpers
- *       to access the data.
+ *    Note, __dynamic_array, __string, __bitmask and __cpumask require special
+ *       helpers to access the data.
  *
  *      For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo)
  *            Use __get_dynamic_array_len(foo) to get the length of the array
@@ -226,6 +236,8 @@
  *
  *      For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus)
  *
+ *      For __cpumask(target_cpus) use __get_cpumask(target_cpus)
+ *
  *
  * Note, that for both the assign and the printk, __entry is the handler
  * to the data structure in the ring buffer, and is defined by the
@@ -288,6 +300,7 @@ TRACE_EVENT(foo_bar,
		__dynamic_array(int,	list,   __length_of(lst))
		__string(	str,	string			)
		__bitmask(	cpus,	num_possible_cpus()	)
+		__cpumask(	cpum				)
		__vstring(	vstr,	fmt,	va		)
	),

@@ -299,9 +312,10 @@ TRACE_EVENT(foo_bar,
		__assign_str(str, string);
		__assign_vstr(vstr, fmt, va);
		__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
+		__assign_cpumask(cpum, cpumask_bits(mask));
	),

-	TP_printk("foo %s %d %s %s %s %s (%s) %s", __entry->foo, __entry->bar,
+	TP_printk("foo %s %d %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,

 /*
  * Notice here the use of some helper functions. This includes:
@@ -345,7 +359,8 @@ TRACE_EVENT(foo_bar,
		  __print_array(__get_dynamic_array(list),
				__get_dynamic_array_len(list) / sizeof(int),
				sizeof(int)),
-		  __get_str(str), __get_bitmask(cpus), __get_str(vstr))
+		  __get_str(str), __get_bitmask(cpus), __get_cpumask(cpus),
+		  __get_str(vstr))
 );

 /*
@@ -542,15 +557,16 @@ DEFINE_EVENT_PRINT(foo_template, foo_with_template_print,

 TRACE_EVENT(foo_rel_loc,

-	TP_PROTO(const char *foo, int bar, unsigned long *mask),
+	TP_PROTO(const char *foo, int bar, unsigned long *mask, const cpumask_t *cpus),

-	TP_ARGS(foo, bar, mask),
+	TP_ARGS(foo, bar, mask, cpus),

	TP_STRUCT__entry(
		__rel_string(	foo,	foo	)
		__field(	int,	bar	)
		__rel_bitmask(	bitmask,
			BITS_PER_BYTE * sizeof(unsigned long)	)
+		__rel_cpumask(	cpumask )
	),

	TP_fast_assign(
@@ -558,10 +574,12 @@ TRACE_EVENT(foo_rel_loc,
		__entry->bar = bar;
		__assign_rel_bitmask(bitmask, mask,
			BITS_PER_BYTE * sizeof(unsigned long));
+		__assign_rel_cpumask(cpumask, cpus);
	),

-	TP_printk("foo_rel_loc %s, %d, %s", __get_rel_str(foo), __entry->bar,
-		  __get_rel_bitmask(bitmask))
+	TP_printk("foo_rel_loc %s, %d, %s, %s", __get_rel_str(foo), __entry->bar,
+		  __get_rel_bitmask(bitmask),
+		  __get_rel_cpumask(cpumask))
 );
 #endif

--
2.31.1


_______________________________________________
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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 1/8] DO-NOT-MERGE: tracing: Add __cpumask to denote a trace event field that is a cpumask_t
@ 2022-11-02 18:29   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Steven Rostedt (Google),
	Paul E. McKenney, Peter Zijlstra, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

The trace events have a __bitmask field that can be used for anything
that requires bitmasks. Although currently it is only used for CPU
masks, it could be used in the future for any type of bitmasks.

There is some user space tooling that wants to know if a field is a CPU
mask and not just some random unsigned long bitmask. Introduce
"__cpumask()" helper functions that work the same as the current
__bitmask() helpers but displays in the format file:

  field:__data_loc cpumask_t *[] mask;    offset:36;      size:4; signed:0;

Instead of:

  field:__data_loc unsigned long[] mask;  offset:32;      size:4; signed:0;

The main difference is the type. Instead of "unsigned long" it is
"cpumask_t *". Note, this type field needs to be a real type in the
__dynamic_array() logic that both __cpumask and__bitmask use, but the
comparison field requires it to be a scalar type whereas cpumask_t is a
structure (non-scalar). But everything works when making it a pointer.

Valentin added changes to remove the need of passing in "nr_bits" and the
__cpumask will always use nr_cpumask_bits as its size.

Requested-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/trace/bpf_probe.h                    |  6 ++++
 include/trace/perf.h                         |  6 ++++
 include/trace/stages/stage1_struct_define.h  |  6 ++++
 include/trace/stages/stage2_data_offsets.h   |  6 ++++
 include/trace/stages/stage3_trace_output.h   |  6 ++++
 include/trace/stages/stage4_event_fields.h   |  6 ++++
 include/trace/stages/stage5_get_offsets.h    |  6 ++++
 include/trace/stages/stage6_event_callback.h | 20 ++++++++++++
 include/trace/stages/stage7_class_define.h   |  2 ++
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++++++++++-----
 11 files changed, 91 insertions(+), 9 deletions(-)

diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h
index 6a13220d2d27b..155c495b89ead 100644
--- a/include/trace/bpf_probe.h
+++ b/include/trace/bpf_probe.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -40,6 +43,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/perf.h b/include/trace/perf.h
index 5800d13146c3d..8f3bf1e177070 100644
--- a/include/trace/perf.h
+++ b/include/trace/perf.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -41,6 +44,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/stages/stage1_struct_define.h b/include/trace/stages/stage1_struct_define.h
index 1b7bab60434c1..69e0dae453bfa 100644
--- a/include/trace/stages/stage1_struct_define.h
+++ b/include/trace/stages/stage1_struct_define.h
@@ -32,6 +32,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(char, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(char, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -47,6 +50,9 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(char, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(char, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage2_data_offsets.h b/include/trace/stages/stage2_data_offsets.h
index 1b7a8f764fddd..469b6a64293de 100644
--- a/include/trace/stages/stage2_data_offsets.h
+++ b/include/trace/stages/stage2_data_offsets.h
@@ -38,6 +38,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -53,5 +56,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage3_trace_output.h b/include/trace/stages/stage3_trace_output.h
index e3b183e9d18ea..66374df61ed30 100644
--- a/include/trace/stages/stage3_trace_output.h
+++ b/include/trace/stages/stage3_trace_output.h
@@ -42,6 +42,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_cpumask
+#define __get_cpumask(field) __get_bitmask(field)
+
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field)						\
	({								\
@@ -51,6 +54,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) __get_rel_bitmask(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field)	((struct sockaddr *)__get_dynamic_array(field))

diff --git a/include/trace/stages/stage4_event_fields.h b/include/trace/stages/stage4_event_fields.h
index a8fb25f39a99d..f2990d22313cf 100644
--- a/include/trace/stages/stage4_event_fields.h
+++ b/include/trace/stages/stage4_event_fields.h
@@ -46,6 +46,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(cpumask_t *, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -64,5 +67,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(cpumask_t *, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage5_get_offsets.h b/include/trace/stages/stage5_get_offsets.h
index fba4c24ed9e60..ac5c24d3beeb2 100644
--- a/include/trace/stages/stage5_get_offsets.h
+++ b/include/trace/stages/stage5_get_offsets.h
@@ -82,10 +82,16 @@
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __bitmask(item, nr_cpumask_bits)
+
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_bitmask(item, nr_cpumask_bits)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage6_event_callback.h b/include/trace/stages/stage6_event_callback.h
index 3c554a5853204..49c32394b53fb 100644
--- a/include/trace/stages/stage6_event_callback.h
+++ b/include/trace/stages/stage6_event_callback.h
@@ -57,6 +57,16 @@
 #define __assign_bitmask(dst, src, nr_bits)					\
	memcpy(__get_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
+#undef __assign_cpumask
+#define __assign_cpumask(dst, src)					\
+	memcpy(__get_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -98,6 +108,16 @@
 #define __assign_rel_bitmask(dst, src, nr_bits)					\
	memcpy(__get_rel_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
+#undef __assign_rel_cpumask
+#define __assign_rel_cpumask(dst, src)					\
+	memcpy(__get_rel_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage7_class_define.h b/include/trace/stages/stage7_class_define.h
index 8a7ec24c246dd..8795429f388b0 100644
--- a/include/trace/stages/stage7_class_define.h
+++ b/include/trace/stages/stage7_class_define.h
@@ -13,11 +13,13 @@
 #undef __get_dynamic_array_len
 #undef __get_str
 #undef __get_bitmask
+#undef __get_cpumask
 #undef __get_sockaddr
 #undef __get_rel_dynamic_array
 #undef __get_rel_dynamic_array_len
 #undef __get_rel_str
 #undef __get_rel_bitmask
+#undef __get_rel_cpumask
 #undef __get_rel_sockaddr
 #undef __print_array
 #undef __print_hex_dump
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index 608c4ae3b08a3..ecc7db237f2ef 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -50,7 +50,7 @@ static void do_simple_thread_func(int cnt, const char *fmt, ...)

	trace_foo_with_template_print("I have to be different", cnt);

-	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask);
+	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask, current->cpus_ptr);
 }

 static void simple_thread_func(int cnt)
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 1a92226202fc5..fb4548a44153c 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -200,6 +200,16 @@
  *
  *         __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits);
  *
+ *   __cpumask: This is pretty much the same as __bitmask but is specific for
+ *         CPU masks. The type displayed to the user via the format files will
+ *         be "cpumaks_t" such that user space may deal with them differently
+ *         if they choose to do so, and the bits is always set to nr_cpumask_bits.
+ *
+ *         __cpumask(target_cpu)
+ *
+ *         To assign a cpumask, use the __assign_cpumask() helper macro.
+ *
+ *         __assign_cpumask(target_cpus, cpumask_bits(bar));
  *
  * fast_assign: This is a C like function that is used to store the items
  *    into the ring buffer. A special variable called "__entry" will be the
@@ -212,8 +222,8 @@
  *    This is also used to print out the data from the trace files.
  *    Again, the __entry macro is used to access the data from the ring buffer.
  *
- *    Note, __dynamic_array, __string, and __bitmask require special helpers
- *       to access the data.
+ *    Note, __dynamic_array, __string, __bitmask and __cpumask require special
+ *       helpers to access the data.
  *
  *      For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo)
  *            Use __get_dynamic_array_len(foo) to get the length of the array
@@ -226,6 +236,8 @@
  *
  *      For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus)
  *
+ *      For __cpumask(target_cpus) use __get_cpumask(target_cpus)
+ *
  *
  * Note, that for both the assign and the printk, __entry is the handler
  * to the data structure in the ring buffer, and is defined by the
@@ -288,6 +300,7 @@ TRACE_EVENT(foo_bar,
		__dynamic_array(int,	list,   __length_of(lst))
		__string(	str,	string			)
		__bitmask(	cpus,	num_possible_cpus()	)
+		__cpumask(	cpum				)
		__vstring(	vstr,	fmt,	va		)
	),

@@ -299,9 +312,10 @@ TRACE_EVENT(foo_bar,
		__assign_str(str, string);
		__assign_vstr(vstr, fmt, va);
		__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
+		__assign_cpumask(cpum, cpumask_bits(mask));
	),

-	TP_printk("foo %s %d %s %s %s %s (%s) %s", __entry->foo, __entry->bar,
+	TP_printk("foo %s %d %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,

 /*
  * Notice here the use of some helper functions. This includes:
@@ -345,7 +359,8 @@ TRACE_EVENT(foo_bar,
		  __print_array(__get_dynamic_array(list),
				__get_dynamic_array_len(list) / sizeof(int),
				sizeof(int)),
-		  __get_str(str), __get_bitmask(cpus), __get_str(vstr))
+		  __get_str(str), __get_bitmask(cpus), __get_cpumask(cpus),
+		  __get_str(vstr))
 );

 /*
@@ -542,15 +557,16 @@ DEFINE_EVENT_PRINT(foo_template, foo_with_template_print,

 TRACE_EVENT(foo_rel_loc,

-	TP_PROTO(const char *foo, int bar, unsigned long *mask),
+	TP_PROTO(const char *foo, int bar, unsigned long *mask, const cpumask_t *cpus),

-	TP_ARGS(foo, bar, mask),
+	TP_ARGS(foo, bar, mask, cpus),

	TP_STRUCT__entry(
		__rel_string(	foo,	foo	)
		__field(	int,	bar	)
		__rel_bitmask(	bitmask,
			BITS_PER_BYTE * sizeof(unsigned long)	)
+		__rel_cpumask(	cpumask )
	),

	TP_fast_assign(
@@ -558,10 +574,12 @@ TRACE_EVENT(foo_rel_loc,
		__entry->bar = bar;
		__assign_rel_bitmask(bitmask, mask,
			BITS_PER_BYTE * sizeof(unsigned long));
+		__assign_rel_cpumask(cpumask, cpus);
	),

-	TP_printk("foo_rel_loc %s, %d, %s", __get_rel_str(foo), __entry->bar,
-		  __get_rel_bitmask(bitmask))
+	TP_printk("foo_rel_loc %s, %d, %s, %s", __get_rel_str(foo), __entry->bar,
+		  __get_rel_bitmask(bitmask),
+		  __get_rel_cpumask(cpumask))
 );
 #endif

--
2.31.1


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 1/8] DO-NOT-MERGE: tracing: Add __cpumask to denote a trace event field that is a cpumask_t
@ 2022-11-02 18:29   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Steven Rostedt (Google),
	Paul E. McKenney, Peter Zijlstra, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

The trace events have a __bitmask field that can be used for anything
that requires bitmasks. Although currently it is only used for CPU
masks, it could be used in the future for any type of bitmasks.

There is some user space tooling that wants to know if a field is a CPU
mask and not just some random unsigned long bitmask. Introduce
"__cpumask()" helper functions that work the same as the current
__bitmask() helpers but displays in the format file:

  field:__data_loc cpumask_t *[] mask;    offset:36;      size:4; signed:0;

Instead of:

  field:__data_loc unsigned long[] mask;  offset:32;      size:4; signed:0;

The main difference is the type. Instead of "unsigned long" it is
"cpumask_t *". Note, this type field needs to be a real type in the
__dynamic_array() logic that both __cpumask and__bitmask use, but the
comparison field requires it to be a scalar type whereas cpumask_t is a
structure (non-scalar). But everything works when making it a pointer.

Valentin added changes to remove the need of passing in "nr_bits" and the
__cpumask will always use nr_cpumask_bits as its size.

Requested-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/trace/bpf_probe.h                    |  6 ++++
 include/trace/perf.h                         |  6 ++++
 include/trace/stages/stage1_struct_define.h  |  6 ++++
 include/trace/stages/stage2_data_offsets.h   |  6 ++++
 include/trace/stages/stage3_trace_output.h   |  6 ++++
 include/trace/stages/stage4_event_fields.h   |  6 ++++
 include/trace/stages/stage5_get_offsets.h    |  6 ++++
 include/trace/stages/stage6_event_callback.h | 20 ++++++++++++
 include/trace/stages/stage7_class_define.h   |  2 ++
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++++++++++-----
 11 files changed, 91 insertions(+), 9 deletions(-)

diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h
index 6a13220d2d27b..155c495b89ead 100644
--- a/include/trace/bpf_probe.h
+++ b/include/trace/bpf_probe.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -40,6 +43,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/perf.h b/include/trace/perf.h
index 5800d13146c3d..8f3bf1e177070 100644
--- a/include/trace/perf.h
+++ b/include/trace/perf.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -41,6 +44,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/stages/stage1_struct_define.h b/include/trace/stages/stage1_struct_define.h
index 1b7bab60434c1..69e0dae453bfa 100644
--- a/include/trace/stages/stage1_struct_define.h
+++ b/include/trace/stages/stage1_struct_define.h
@@ -32,6 +32,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(char, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(char, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -47,6 +50,9 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(char, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(char, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage2_data_offsets.h b/include/trace/stages/stage2_data_offsets.h
index 1b7a8f764fddd..469b6a64293de 100644
--- a/include/trace/stages/stage2_data_offsets.h
+++ b/include/trace/stages/stage2_data_offsets.h
@@ -38,6 +38,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -53,5 +56,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage3_trace_output.h b/include/trace/stages/stage3_trace_output.h
index e3b183e9d18ea..66374df61ed30 100644
--- a/include/trace/stages/stage3_trace_output.h
+++ b/include/trace/stages/stage3_trace_output.h
@@ -42,6 +42,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_cpumask
+#define __get_cpumask(field) __get_bitmask(field)
+
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field)						\
	({								\
@@ -51,6 +54,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) __get_rel_bitmask(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field)	((struct sockaddr *)__get_dynamic_array(field))

diff --git a/include/trace/stages/stage4_event_fields.h b/include/trace/stages/stage4_event_fields.h
index a8fb25f39a99d..f2990d22313cf 100644
--- a/include/trace/stages/stage4_event_fields.h
+++ b/include/trace/stages/stage4_event_fields.h
@@ -46,6 +46,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(cpumask_t *, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -64,5 +67,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(cpumask_t *, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage5_get_offsets.h b/include/trace/stages/stage5_get_offsets.h
index fba4c24ed9e60..ac5c24d3beeb2 100644
--- a/include/trace/stages/stage5_get_offsets.h
+++ b/include/trace/stages/stage5_get_offsets.h
@@ -82,10 +82,16 @@
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __bitmask(item, nr_cpumask_bits)
+
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_bitmask(item, nr_cpumask_bits)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage6_event_callback.h b/include/trace/stages/stage6_event_callback.h
index 3c554a5853204..49c32394b53fb 100644
--- a/include/trace/stages/stage6_event_callback.h
+++ b/include/trace/stages/stage6_event_callback.h
@@ -57,6 +57,16 @@
 #define __assign_bitmask(dst, src, nr_bits)					\
	memcpy(__get_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
+#undef __assign_cpumask
+#define __assign_cpumask(dst, src)					\
+	memcpy(__get_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -98,6 +108,16 @@
 #define __assign_rel_bitmask(dst, src, nr_bits)					\
	memcpy(__get_rel_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
+#undef __assign_rel_cpumask
+#define __assign_rel_cpumask(dst, src)					\
+	memcpy(__get_rel_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage7_class_define.h b/include/trace/stages/stage7_class_define.h
index 8a7ec24c246dd..8795429f388b0 100644
--- a/include/trace/stages/stage7_class_define.h
+++ b/include/trace/stages/stage7_class_define.h
@@ -13,11 +13,13 @@
 #undef __get_dynamic_array_len
 #undef __get_str
 #undef __get_bitmask
+#undef __get_cpumask
 #undef __get_sockaddr
 #undef __get_rel_dynamic_array
 #undef __get_rel_dynamic_array_len
 #undef __get_rel_str
 #undef __get_rel_bitmask
+#undef __get_rel_cpumask
 #undef __get_rel_sockaddr
 #undef __print_array
 #undef __print_hex_dump
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index 608c4ae3b08a3..ecc7db237f2ef 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -50,7 +50,7 @@ static void do_simple_thread_func(int cnt, const char *fmt, ...)

	trace_foo_with_template_print("I have to be different", cnt);

-	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask);
+	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask, current->cpus_ptr);
 }

 static void simple_thread_func(int cnt)
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 1a92226202fc5..fb4548a44153c 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -200,6 +200,16 @@
  *
  *         __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits);
  *
+ *   __cpumask: This is pretty much the same as __bitmask but is specific for
+ *         CPU masks. The type displayed to the user via the format files will
+ *         be "cpumaks_t" such that user space may deal with them differently
+ *         if they choose to do so, and the bits is always set to nr_cpumask_bits.
+ *
+ *         __cpumask(target_cpu)
+ *
+ *         To assign a cpumask, use the __assign_cpumask() helper macro.
+ *
+ *         __assign_cpumask(target_cpus, cpumask_bits(bar));
  *
  * fast_assign: This is a C like function that is used to store the items
  *    into the ring buffer. A special variable called "__entry" will be the
@@ -212,8 +222,8 @@
  *    This is also used to print out the data from the trace files.
  *    Again, the __entry macro is used to access the data from the ring buffer.
  *
- *    Note, __dynamic_array, __string, and __bitmask require special helpers
- *       to access the data.
+ *    Note, __dynamic_array, __string, __bitmask and __cpumask require special
+ *       helpers to access the data.
  *
  *      For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo)
  *            Use __get_dynamic_array_len(foo) to get the length of the array
@@ -226,6 +236,8 @@
  *
  *      For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus)
  *
+ *      For __cpumask(target_cpus) use __get_cpumask(target_cpus)
+ *
  *
  * Note, that for both the assign and the printk, __entry is the handler
  * to the data structure in the ring buffer, and is defined by the
@@ -288,6 +300,7 @@ TRACE_EVENT(foo_bar,
		__dynamic_array(int,	list,   __length_of(lst))
		__string(	str,	string			)
		__bitmask(	cpus,	num_possible_cpus()	)
+		__cpumask(	cpum				)
		__vstring(	vstr,	fmt,	va		)
	),

@@ -299,9 +312,10 @@ TRACE_EVENT(foo_bar,
		__assign_str(str, string);
		__assign_vstr(vstr, fmt, va);
		__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
+		__assign_cpumask(cpum, cpumask_bits(mask));
	),

-	TP_printk("foo %s %d %s %s %s %s (%s) %s", __entry->foo, __entry->bar,
+	TP_printk("foo %s %d %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,

 /*
  * Notice here the use of some helper functions. This includes:
@@ -345,7 +359,8 @@ TRACE_EVENT(foo_bar,
		  __print_array(__get_dynamic_array(list),
				__get_dynamic_array_len(list) / sizeof(int),
				sizeof(int)),
-		  __get_str(str), __get_bitmask(cpus), __get_str(vstr))
+		  __get_str(str), __get_bitmask(cpus), __get_cpumask(cpus),
+		  __get_str(vstr))
 );

 /*
@@ -542,15 +557,16 @@ DEFINE_EVENT_PRINT(foo_template, foo_with_template_print,

 TRACE_EVENT(foo_rel_loc,

-	TP_PROTO(const char *foo, int bar, unsigned long *mask),
+	TP_PROTO(const char *foo, int bar, unsigned long *mask, const cpumask_t *cpus),

-	TP_ARGS(foo, bar, mask),
+	TP_ARGS(foo, bar, mask, cpus),

	TP_STRUCT__entry(
		__rel_string(	foo,	foo	)
		__field(	int,	bar	)
		__rel_bitmask(	bitmask,
			BITS_PER_BYTE * sizeof(unsigned long)	)
+		__rel_cpumask(	cpumask )
	),

	TP_fast_assign(
@@ -558,10 +574,12 @@ TRACE_EVENT(foo_rel_loc,
		__entry->bar = bar;
		__assign_rel_bitmask(bitmask, mask,
			BITS_PER_BYTE * sizeof(unsigned long));
+		__assign_rel_cpumask(cpumask, cpus);
	),

-	TP_printk("foo_rel_loc %s, %d, %s", __get_rel_str(foo), __entry->bar,
-		  __get_rel_bitmask(bitmask))
+	TP_printk("foo_rel_loc %s, %d, %s, %s", __get_rel_str(foo), __entry->bar,
+		  __get_rel_bitmask(bitmask),
+		  __get_rel_cpumask(cpumask))
 );
 #endif

--
2.31.1


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^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 1/8] DO-NOT-MERGE: tracing: Add __cpumask to denote a trace event field that is a cpum
@ 2022-11-02 18:29   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:29 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt (Google),
	David S. Miller, Ingo Molnar, Borislav Petkov, Nicholas Piggin,
	H. Peter Anvin, Guo Ren, Thomas Gleixner,
	Daniel Bristot de Oliveira, Frederic Weisbecker

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

The trace events have a __bitmask field that can be used for anything
that requires bitmasks. Although currently it is only used for CPU
masks, it could be used in the future for any type of bitmasks.

There is some user space tooling that wants to know if a field is a CPU
mask and not just some random unsigned long bitmask. Introduce
"__cpumask()" helper functions that work the same as the current
__bitmask() helpers but displays in the format file:

  field:__data_loc cpumask_t *[] mask;    offset:36;      size:4; signed:0;

Instead of:

  field:__data_loc unsigned long[] mask;  offset:32;      size:4; signed:0;

The main difference is the type. Instead of "unsigned long" it is
"cpumask_t *". Note, this type field needs to be a real type in the
__dynamic_array() logic that both __cpumask and__bitmask use, but the
comparison field requires it to be a scalar type whereas cpumask_t is a
structure (non-scalar). But everything works when making it a pointer.

Valentin added changes to remove the need of passing in "nr_bits" and the
__cpumask will always use nr_cpumask_bits as its size.

Requested-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/trace/bpf_probe.h                    |  6 ++++
 include/trace/perf.h                         |  6 ++++
 include/trace/stages/stage1_struct_define.h  |  6 ++++
 include/trace/stages/stage2_data_offsets.h   |  6 ++++
 include/trace/stages/stage3_trace_output.h   |  6 ++++
 include/trace/stages/stage4_event_fields.h   |  6 ++++
 include/trace/stages/stage5_get_offsets.h    |  6 ++++
 include/trace/stages/stage6_event_callback.h | 20 ++++++++++++
 include/trace/stages/stage7_class_define.h   |  2 ++
 samples/trace_events/trace-events-sample.c   |  2 +-
 samples/trace_events/trace-events-sample.h   | 34 +++++++++++++++-----
 11 files changed, 91 insertions(+), 9 deletions(-)

diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h
index 6a13220d2d27b..155c495b89ead 100644
--- a/include/trace/bpf_probe.h
+++ b/include/trace/bpf_probe.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -40,6 +43,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/perf.h b/include/trace/perf.h
index 5800d13146c3d..8f3bf1e177070 100644
--- a/include/trace/perf.h
+++ b/include/trace/perf.h
@@ -21,6 +21,9 @@
 #undef __get_bitmask
 #define __get_bitmask(field) (char *)__get_dynamic_array(field)

+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field) ((struct sockaddr *)__get_dynamic_array(field))

@@ -41,6 +44,9 @@
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
 #undef __get_rel_sockaddr
 #define __get_rel_sockaddr(field) ((struct sockaddr *)__get_rel_dynamic_array(field))

diff --git a/include/trace/stages/stage1_struct_define.h b/include/trace/stages/stage1_struct_define.h
index 1b7bab60434c1..69e0dae453bfa 100644
--- a/include/trace/stages/stage1_struct_define.h
+++ b/include/trace/stages/stage1_struct_define.h
@@ -32,6 +32,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(char, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(char, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -47,6 +50,9 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(char, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(char, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage2_data_offsets.h b/include/trace/stages/stage2_data_offsets.h
index 1b7a8f764fddd..469b6a64293de 100644
--- a/include/trace/stages/stage2_data_offsets.h
+++ b/include/trace/stages/stage2_data_offsets.h
@@ -38,6 +38,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -53,5 +56,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage3_trace_output.h b/include/trace/stages/stage3_trace_output.h
index e3b183e9d18ea..66374df61ed30 100644
--- a/include/trace/stages/stage3_trace_output.h
+++ b/include/trace/stages/stage3_trace_output.h
@@ -42,6 +42,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_cpumask
+#define __get_cpumask(field) __get_bitmask(field)
+
 #undef __get_rel_bitmask
 #define __get_rel_bitmask(field)						\
	({								\
@@ -51,6 +54,9 @@
		trace_print_bitmask_seq(p, __bitmask, __bitmask_size);	\
	})

+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) __get_rel_bitmask(field)
+
 #undef __get_sockaddr
 #define __get_sockaddr(field)	((struct sockaddr *)__get_dynamic_array(field))

diff --git a/include/trace/stages/stage4_event_fields.h b/include/trace/stages/stage4_event_fields.h
index a8fb25f39a99d..f2990d22313cf 100644
--- a/include/trace/stages/stage4_event_fields.h
+++ b/include/trace/stages/stage4_event_fields.h
@@ -46,6 +46,9 @@
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(cpumask_t *, item, -1)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -64,5 +67,8 @@
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, -1)

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(cpumask_t *, item, -1)
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)
diff --git a/include/trace/stages/stage5_get_offsets.h b/include/trace/stages/stage5_get_offsets.h
index fba4c24ed9e60..ac5c24d3beeb2 100644
--- a/include/trace/stages/stage5_get_offsets.h
+++ b/include/trace/stages/stage5_get_offsets.h
@@ -82,10 +82,16 @@
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __bitmask(item, nr_cpumask_bits)
+
 #undef __rel_bitmask
 #define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item,	\
					 __bitmask_size_in_longs(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_bitmask(item, nr_cpumask_bits)
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage6_event_callback.h b/include/trace/stages/stage6_event_callback.h
index 3c554a5853204..49c32394b53fb 100644
--- a/include/trace/stages/stage6_event_callback.h
+++ b/include/trace/stages/stage6_event_callback.h
@@ -57,6 +57,16 @@
 #define __assign_bitmask(dst, src, nr_bits)					\
	memcpy(__get_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __cpumask
+#define __cpumask(item) __dynamic_array(unsigned long, item, -1)
+
+#undef __get_cpumask
+#define __get_cpumask(field) (char *)__get_dynamic_array(field)
+
+#undef __assign_cpumask
+#define __assign_cpumask(dst, src)					\
+	memcpy(__get_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __sockaddr
 #define __sockaddr(field, len) __dynamic_array(u8, field, len)

@@ -98,6 +108,16 @@
 #define __assign_rel_bitmask(dst, src, nr_bits)					\
	memcpy(__get_rel_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits))

+#undef __rel_cpumask
+#define __rel_cpumask(item) __rel_dynamic_array(unsigned long, item, -1)
+
+#undef __get_rel_cpumask
+#define __get_rel_cpumask(field) (char *)__get_rel_dynamic_array(field)
+
+#undef __assign_rel_cpumask
+#define __assign_rel_cpumask(dst, src)					\
+	memcpy(__get_rel_cpumask(dst), (src), __bitmask_size_in_bytes(nr_cpumask_bits))
+
 #undef __rel_sockaddr
 #define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)

diff --git a/include/trace/stages/stage7_class_define.h b/include/trace/stages/stage7_class_define.h
index 8a7ec24c246dd..8795429f388b0 100644
--- a/include/trace/stages/stage7_class_define.h
+++ b/include/trace/stages/stage7_class_define.h
@@ -13,11 +13,13 @@
 #undef __get_dynamic_array_len
 #undef __get_str
 #undef __get_bitmask
+#undef __get_cpumask
 #undef __get_sockaddr
 #undef __get_rel_dynamic_array
 #undef __get_rel_dynamic_array_len
 #undef __get_rel_str
 #undef __get_rel_bitmask
+#undef __get_rel_cpumask
 #undef __get_rel_sockaddr
 #undef __print_array
 #undef __print_hex_dump
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index 608c4ae3b08a3..ecc7db237f2ef 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -50,7 +50,7 @@ static void do_simple_thread_func(int cnt, const char *fmt, ...)

	trace_foo_with_template_print("I have to be different", cnt);

-	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask);
+	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask, current->cpus_ptr);
 }

 static void simple_thread_func(int cnt)
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 1a92226202fc5..fb4548a44153c 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -200,6 +200,16 @@
  *
  *         __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits);
  *
+ *   __cpumask: This is pretty much the same as __bitmask but is specific for
+ *         CPU masks. The type displayed to the user via the format files will
+ *         be "cpumaks_t" such that user space may deal with them differently
+ *         if they choose to do so, and the bits is always set to nr_cpumask_bits.
+ *
+ *         __cpumask(target_cpu)
+ *
+ *         To assign a cpumask, use the __assign_cpumask() helper macro.
+ *
+ *         __assign_cpumask(target_cpus, cpumask_bits(bar));
  *
  * fast_assign: This is a C like function that is used to store the items
  *    into the ring buffer. A special variable called "__entry" will be the
@@ -212,8 +222,8 @@
  *    This is also used to print out the data from the trace files.
  *    Again, the __entry macro is used to access the data from the ring buffer.
  *
- *    Note, __dynamic_array, __string, and __bitmask require special helpers
- *       to access the data.
+ *    Note, __dynamic_array, __string, __bitmask and __cpumask require special
+ *       helpers to access the data.
  *
  *      For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo)
  *            Use __get_dynamic_array_len(foo) to get the length of the array
@@ -226,6 +236,8 @@
  *
  *      For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus)
  *
+ *      For __cpumask(target_cpus) use __get_cpumask(target_cpus)
+ *
  *
  * Note, that for both the assign and the printk, __entry is the handler
  * to the data structure in the ring buffer, and is defined by the
@@ -288,6 +300,7 @@ TRACE_EVENT(foo_bar,
		__dynamic_array(int,	list,   __length_of(lst))
		__string(	str,	string			)
		__bitmask(	cpus,	num_possible_cpus()	)
+		__cpumask(	cpum				)
		__vstring(	vstr,	fmt,	va		)
	),

@@ -299,9 +312,10 @@ TRACE_EVENT(foo_bar,
		__assign_str(str, string);
		__assign_vstr(vstr, fmt, va);
		__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
+		__assign_cpumask(cpum, cpumask_bits(mask));
	),

-	TP_printk("foo %s %d %s %s %s %s (%s) %s", __entry->foo, __entry->bar,
+	TP_printk("foo %s %d %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,

 /*
  * Notice here the use of some helper functions. This includes:
@@ -345,7 +359,8 @@ TRACE_EVENT(foo_bar,
		  __print_array(__get_dynamic_array(list),
				__get_dynamic_array_len(list) / sizeof(int),
				sizeof(int)),
-		  __get_str(str), __get_bitmask(cpus), __get_str(vstr))
+		  __get_str(str), __get_bitmask(cpus), __get_cpumask(cpus),
+		  __get_str(vstr))
 );

 /*
@@ -542,15 +557,16 @@ DEFINE_EVENT_PRINT(foo_template, foo_with_template_print,

 TRACE_EVENT(foo_rel_loc,

-	TP_PROTO(const char *foo, int bar, unsigned long *mask),
+	TP_PROTO(const char *foo, int bar, unsigned long *mask, const cpumask_t *cpus),

-	TP_ARGS(foo, bar, mask),
+	TP_ARGS(foo, bar, mask, cpus),

	TP_STRUCT__entry(
		__rel_string(	foo,	foo	)
		__field(	int,	bar	)
		__rel_bitmask(	bitmask,
			BITS_PER_BYTE * sizeof(unsigned long)	)
+		__rel_cpumask(	cpumask )
	),

	TP_fast_assign(
@@ -558,10 +574,12 @@ TRACE_EVENT(foo_rel_loc,
		__entry->bar = bar;
		__assign_rel_bitmask(bitmask, mask,
			BITS_PER_BYTE * sizeof(unsigned long));
+		__assign_rel_cpumask(cpumask, cpus);
	),

-	TP_printk("foo_rel_loc %s, %d, %s", __get_rel_str(foo), __entry->bar,
-		  __get_rel_bitmask(bitmask))
+	TP_printk("foo_rel_loc %s, %d, %s, %s", __get_rel_str(foo), __entry->bar,
+		  __get_rel_bitmask(bitmask),
+		  __get_rel_cpumask(cpumask))
 );
 #endif

--
2.31.1

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 2/8] trace: Add trace_ipi_send_cpumask()
  2022-11-02 18:29 ` Valentin Schneider
                     ` (3 preceding siblings ...)
  (?)
@ 2022-11-02 18:33   ` Valentin Schneider
  -1 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

trace_ipi_raise() is unsuitable for generically tracing IPI sources due to
its "reason" argument being an uninformative string (on arm64 all you get
is "Function call interrupts" for SMP calls).

Add a variant of it that takes a exports a target CPU, a callsite and a
callback.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 include/trace/events/ipi.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/trace/events/ipi.h b/include/trace/events/ipi.h
index 0be71dad6ec03..b1125dc27682c 100644
--- a/include/trace/events/ipi.h
+++ b/include/trace/events/ipi.h
@@ -35,6 +35,28 @@ TRACE_EVENT(ipi_raise,
 	TP_printk("target_mask=%s (%s)", __get_bitmask(target_cpus), __entry->reason)
 );
 
+TRACE_EVENT(ipi_send_cpumask,
+
+	TP_PROTO(const struct cpumask *cpumask, unsigned long callsite, void *callback),
+
+	TP_ARGS(cpumask, callsite, callback),
+
+	TP_STRUCT__entry(
+		__cpumask(cpumask)
+		__field(void *, callsite)
+		__field(void *, callback)
+	),
+
+	TP_fast_assign(
+		__assign_cpumask(cpumask, cpumask_bits(cpumask));
+		__entry->callsite = (void *)callsite;
+		__entry->callback = callback;
+	),
+
+	TP_printk("cpumask=%s callsite=%pS callback=%pS",
+		  __get_cpumask(cpumask), __entry->callsite, __entry->callback)
+);
+
 DECLARE_EVENT_CLASS(ipi_handler,
 
 	TP_PROTO(const char *reason),
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 2/8] trace: Add trace_ipi_send_cpumask()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

trace_ipi_raise() is unsuitable for generically tracing IPI sources due to
its "reason" argument being an uninformative string (on arm64 all you get
is "Function call interrupts" for SMP calls).

Add a variant of it that takes a exports a target CPU, a callsite and a
callback.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 include/trace/events/ipi.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/trace/events/ipi.h b/include/trace/events/ipi.h
index 0be71dad6ec03..b1125dc27682c 100644
--- a/include/trace/events/ipi.h
+++ b/include/trace/events/ipi.h
@@ -35,6 +35,28 @@ TRACE_EVENT(ipi_raise,
 	TP_printk("target_mask=%s (%s)", __get_bitmask(target_cpus), __entry->reason)
 );
 
+TRACE_EVENT(ipi_send_cpumask,
+
+	TP_PROTO(const struct cpumask *cpumask, unsigned long callsite, void *callback),
+
+	TP_ARGS(cpumask, callsite, callback),
+
+	TP_STRUCT__entry(
+		__cpumask(cpumask)
+		__field(void *, callsite)
+		__field(void *, callback)
+	),
+
+	TP_fast_assign(
+		__assign_cpumask(cpumask, cpumask_bits(cpumask));
+		__entry->callsite = (void *)callsite;
+		__entry->callback = callback;
+	),
+
+	TP_printk("cpumask=%s callsite=%pS callback=%pS",
+		  __get_cpumask(cpumask), __entry->callsite, __entry->callback)
+);
+
 DECLARE_EVENT_CLASS(ipi_handler,
 
 	TP_PROTO(const char *reason),
-- 
2.31.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 2/8] trace: Add trace_ipi_send_cpumask()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

trace_ipi_raise() is unsuitable for generically tracing IPI sources due to
its "reason" argument being an uninformative string (on arm64 all you get
is "Function call interrupts" for SMP calls).

Add a variant of it that takes a exports a target CPU, a callsite and a
callback.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 include/trace/events/ipi.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/trace/events/ipi.h b/include/trace/events/ipi.h
index 0be71dad6ec03..b1125dc27682c 100644
--- a/include/trace/events/ipi.h
+++ b/include/trace/events/ipi.h
@@ -35,6 +35,28 @@ TRACE_EVENT(ipi_raise,
 	TP_printk("target_mask=%s (%s)", __get_bitmask(target_cpus), __entry->reason)
 );
 
+TRACE_EVENT(ipi_send_cpumask,
+
+	TP_PROTO(const struct cpumask *cpumask, unsigned long callsite, void *callback),
+
+	TP_ARGS(cpumask, callsite, callback),
+
+	TP_STRUCT__entry(
+		__cpumask(cpumask)
+		__field(void *, callsite)
+		__field(void *, callback)
+	),
+
+	TP_fast_assign(
+		__assign_cpumask(cpumask, cpumask_bits(cpumask));
+		__entry->callsite = (void *)callsite;
+		__entry->callback = callback;
+	),
+
+	TP_printk("cpumask=%s callsite=%pS callback=%pS",
+		  __get_cpumask(cpumask), __entry->callsite, __entry->callback)
+);
+
 DECLARE_EVENT_CLASS(ipi_handler,
 
 	TP_PROTO(const char *reason),
-- 
2.31.1


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 2/8] trace: Add trace_ipi_send_cpumask()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Borislav Petkov, Nicholas Piggin, H. Peter Anvin,
	Guo Ren, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

trace_ipi_raise() is unsuitable for generically tracing IPI sources due to
its "reason" argument being an uninformative string (on arm64 all you get
is "Function call interrupts" for SMP calls).

Add a variant of it that takes a exports a target CPU, a callsite and a
callback.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 include/trace/events/ipi.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/trace/events/ipi.h b/include/trace/events/ipi.h
index 0be71dad6ec03..b1125dc27682c 100644
--- a/include/trace/events/ipi.h
+++ b/include/trace/events/ipi.h
@@ -35,6 +35,28 @@ TRACE_EVENT(ipi_raise,
 	TP_printk("target_mask=%s (%s)", __get_bitmask(target_cpus), __entry->reason)
 );
 
+TRACE_EVENT(ipi_send_cpumask,
+
+	TP_PROTO(const struct cpumask *cpumask, unsigned long callsite, void *callback),
+
+	TP_ARGS(cpumask, callsite, callback),
+
+	TP_STRUCT__entry(
+		__cpumask(cpumask)
+		__field(void *, callsite)
+		__field(void *, callback)
+	),
+
+	TP_fast_assign(
+		__assign_cpumask(cpumask, cpumask_bits(cpumask));
+		__entry->callsite = (void *)callsite;
+		__entry->callback = callback;
+	),
+
+	TP_printk("cpumask=%s callsite=%pS callback=%pS",
+		  __get_cpumask(cpumask), __entry->callsite, __entry->callback)
+);
+
 DECLARE_EVENT_CLASS(ipi_handler,
 
 	TP_PROTO(const char *reason),
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 2/8] trace: Add trace_ipi_send_cpumask()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

trace_ipi_raise() is unsuitable for generically tracing IPI sources due to
its "reason" argument being an uninformative string (on arm64 all you get
is "Function call interrupts" for SMP calls).

Add a variant of it that takes a exports a target CPU, a callsite and a
callback.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 include/trace/events/ipi.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/trace/events/ipi.h b/include/trace/events/ipi.h
index 0be71dad6ec03..b1125dc27682c 100644
--- a/include/trace/events/ipi.h
+++ b/include/trace/events/ipi.h
@@ -35,6 +35,28 @@ TRACE_EVENT(ipi_raise,
 	TP_printk("target_mask=%s (%s)", __get_bitmask(target_cpus), __entry->reason)
 );
 
+TRACE_EVENT(ipi_send_cpumask,
+
+	TP_PROTO(const struct cpumask *cpumask, unsigned long callsite, void *callback),
+
+	TP_ARGS(cpumask, callsite, callback),
+
+	TP_STRUCT__entry(
+		__cpumask(cpumask)
+		__field(void *, callsite)
+		__field(void *, callback)
+	),
+
+	TP_fast_assign(
+		__assign_cpumask(cpumask, cpumask_bits(cpumask));
+		__entry->callsite = (void *)callsite;
+		__entry->callback = callback;
+	),
+
+	TP_printk("cpumask=%s callsite=%pS callback=%pS",
+		  __get_cpumask(cpumask), __entry->callsite, __entry->callback)
+);
+
 DECLARE_EVENT_CLASS(ipi_handler,
 
 	TP_PROTO(const char *reason),
-- 
2.31.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 2/8] trace: Add trace_ipi_send_cpumask()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

trace_ipi_raise() is unsuitable for generically tracing IPI sources due to
its "reason" argument being an uninformative string (on arm64 all you get
is "Function call interrupts" for SMP calls).

Add a variant of it that takes a exports a target CPU, a callsite and a
callback.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 include/trace/events/ipi.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/trace/events/ipi.h b/include/trace/events/ipi.h
index 0be71dad6ec03..b1125dc27682c 100644
--- a/include/trace/events/ipi.h
+++ b/include/trace/events/ipi.h
@@ -35,6 +35,28 @@ TRACE_EVENT(ipi_raise,
 	TP_printk("target_mask=%s (%s)", __get_bitmask(target_cpus), __entry->reason)
 );
 
+TRACE_EVENT(ipi_send_cpumask,
+
+	TP_PROTO(const struct cpumask *cpumask, unsigned long callsite, void *callback),
+
+	TP_ARGS(cpumask, callsite, callback),
+
+	TP_STRUCT__entry(
+		__cpumask(cpumask)
+		__field(void *, callsite)
+		__field(void *, callback)
+	),
+
+	TP_fast_assign(
+		__assign_cpumask(cpumask, cpumask_bits(cpumask));
+		__entry->callsite = (void *)callsite;
+		__entry->callback = callback;
+	),
+
+	TP_printk("cpumask=%s callsite=%pS callback=%pS",
+		  __get_cpumask(cpumask), __entry->callsite, __entry->callback)
+);
+
 DECLARE_EVENT_CLASS(ipi_handler,
 
 	TP_PROTO(const char *reason),
-- 
2.31.1

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 3/8] sched, smp: Trace IPIs sent via send_call_function_single_ipi()
  2022-11-02 18:29 ` Valentin Schneider
                     ` (3 preceding siblings ...)
  (?)
@ 2022-11-02 18:33   ` Valentin Schneider
  -1 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

send_call_function_single_ipi() is the thing that sends IPIs at the bottom
of smp_call_function*() via either generic_exec_single() or
smp_call_function_many_cond(). Give it an IPI-related tracepoint.

Note that this ends up tracing any IPI sent via __smp_call_single_queue(),
which covers __ttwu_queue_wakelist() and irq_work_queue_on() "for free".

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 arch/arm/kernel/smp.c   | 3 ---
 arch/arm64/kernel/smp.c | 1 -
 kernel/sched/core.c     | 7 +++++--
 kernel/smp.c            | 4 ++++
 4 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 978db2d96b446..3b280d55c1c40 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -48,9 +48,6 @@
 #include <asm/mach/arch.h>
 #include <asm/mpu.h>
 
-#define CREATE_TRACE_POINTS
-#include <trace/events/ipi.h>
-
 /*
  * as from 2.5, kernels no longer have an init_tasks structure
  * so we need some other way of telling a new secondary core
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index ffc5d76cf6955..937d2623e06ba 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -51,7 +51,6 @@
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
-#define CREATE_TRACE_POINTS
 #include <trace/events/ipi.h>
 
 DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index cb2aa2b54c7a4..02181f8072b5f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -81,6 +81,7 @@
 #include <linux/sched/rseq_api.h>
 #include <trace/events/sched.h>
 #undef CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
 
 #include "sched.h"
 #include "stats.h"
@@ -3746,10 +3747,12 @@ void send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
-	if (!set_nr_if_polling(rq->idle))
+	if (!set_nr_if_polling(rq->idle)) {
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	else
+	} else {
 		trace_sched_wake_idle_without_ipi(cpu);
+	}
 }
 
 /*
diff --git a/kernel/smp.c b/kernel/smp.c
index 06a413987a14a..e2ca1e2f31274 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -26,6 +26,10 @@
 #include <linux/sched/debug.h>
 #include <linux/jump_label.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
+#undef CREATE_TRACE_POINTS
+
 #include "smpboot.h"
 #include "sched/smp.h"
 
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 3/8] sched, smp: Trace IPIs sent via send_call_function_single_ipi()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

send_call_function_single_ipi() is the thing that sends IPIs at the bottom
of smp_call_function*() via either generic_exec_single() or
smp_call_function_many_cond(). Give it an IPI-related tracepoint.

Note that this ends up tracing any IPI sent via __smp_call_single_queue(),
which covers __ttwu_queue_wakelist() and irq_work_queue_on() "for free".

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 arch/arm/kernel/smp.c   | 3 ---
 arch/arm64/kernel/smp.c | 1 -
 kernel/sched/core.c     | 7 +++++--
 kernel/smp.c            | 4 ++++
 4 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 978db2d96b446..3b280d55c1c40 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -48,9 +48,6 @@
 #include <asm/mach/arch.h>
 #include <asm/mpu.h>
 
-#define CREATE_TRACE_POINTS
-#include <trace/events/ipi.h>
-
 /*
  * as from 2.5, kernels no longer have an init_tasks structure
  * so we need some other way of telling a new secondary core
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index ffc5d76cf6955..937d2623e06ba 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -51,7 +51,6 @@
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
-#define CREATE_TRACE_POINTS
 #include <trace/events/ipi.h>
 
 DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index cb2aa2b54c7a4..02181f8072b5f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -81,6 +81,7 @@
 #include <linux/sched/rseq_api.h>
 #include <trace/events/sched.h>
 #undef CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
 
 #include "sched.h"
 #include "stats.h"
@@ -3746,10 +3747,12 @@ void send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
-	if (!set_nr_if_polling(rq->idle))
+	if (!set_nr_if_polling(rq->idle)) {
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	else
+	} else {
 		trace_sched_wake_idle_without_ipi(cpu);
+	}
 }
 
 /*
diff --git a/kernel/smp.c b/kernel/smp.c
index 06a413987a14a..e2ca1e2f31274 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -26,6 +26,10 @@
 #include <linux/sched/debug.h>
 #include <linux/jump_label.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
+#undef CREATE_TRACE_POINTS
+
 #include "smpboot.h"
 #include "sched/smp.h"
 
-- 
2.31.1


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 3/8] sched, smp: Trace IPIs sent via send_call_function_single_ipi()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Borislav Petkov, Nicholas Piggin, H. Peter Anvin,
	Guo Ren, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

send_call_function_single_ipi() is the thing that sends IPIs at the bottom
of smp_call_function*() via either generic_exec_single() or
smp_call_function_many_cond(). Give it an IPI-related tracepoint.

Note that this ends up tracing any IPI sent via __smp_call_single_queue(),
which covers __ttwu_queue_wakelist() and irq_work_queue_on() "for free".

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 arch/arm/kernel/smp.c   | 3 ---
 arch/arm64/kernel/smp.c | 1 -
 kernel/sched/core.c     | 7 +++++--
 kernel/smp.c            | 4 ++++
 4 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 978db2d96b446..3b280d55c1c40 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -48,9 +48,6 @@
 #include <asm/mach/arch.h>
 #include <asm/mpu.h>
 
-#define CREATE_TRACE_POINTS
-#include <trace/events/ipi.h>
-
 /*
  * as from 2.5, kernels no longer have an init_tasks structure
  * so we need some other way of telling a new secondary core
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index ffc5d76cf6955..937d2623e06ba 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -51,7 +51,6 @@
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
-#define CREATE_TRACE_POINTS
 #include <trace/events/ipi.h>
 
 DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index cb2aa2b54c7a4..02181f8072b5f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -81,6 +81,7 @@
 #include <linux/sched/rseq_api.h>
 #include <trace/events/sched.h>
 #undef CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
 
 #include "sched.h"
 #include "stats.h"
@@ -3746,10 +3747,12 @@ void send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
-	if (!set_nr_if_polling(rq->idle))
+	if (!set_nr_if_polling(rq->idle)) {
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	else
+	} else {
 		trace_sched_wake_idle_without_ipi(cpu);
+	}
 }
 
 /*
diff --git a/kernel/smp.c b/kernel/smp.c
index 06a413987a14a..e2ca1e2f31274 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -26,6 +26,10 @@
 #include <linux/sched/debug.h>
 #include <linux/jump_label.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
+#undef CREATE_TRACE_POINTS
+
 #include "smpboot.h"
 #include "sched/smp.h"
 
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 3/8] sched, smp: Trace IPIs sent via send_call_function_single_ipi()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

send_call_function_single_ipi() is the thing that sends IPIs at the bottom
of smp_call_function*() via either generic_exec_single() or
smp_call_function_many_cond(). Give it an IPI-related tracepoint.

Note that this ends up tracing any IPI sent via __smp_call_single_queue(),
which covers __ttwu_queue_wakelist() and irq_work_queue_on() "for free".

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 arch/arm/kernel/smp.c   | 3 ---
 arch/arm64/kernel/smp.c | 1 -
 kernel/sched/core.c     | 7 +++++--
 kernel/smp.c            | 4 ++++
 4 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 978db2d96b446..3b280d55c1c40 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -48,9 +48,6 @@
 #include <asm/mach/arch.h>
 #include <asm/mpu.h>
 
-#define CREATE_TRACE_POINTS
-#include <trace/events/ipi.h>
-
 /*
  * as from 2.5, kernels no longer have an init_tasks structure
  * so we need some other way of telling a new secondary core
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index ffc5d76cf6955..937d2623e06ba 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -51,7 +51,6 @@
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
-#define CREATE_TRACE_POINTS
 #include <trace/events/ipi.h>
 
 DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index cb2aa2b54c7a4..02181f8072b5f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -81,6 +81,7 @@
 #include <linux/sched/rseq_api.h>
 #include <trace/events/sched.h>
 #undef CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
 
 #include "sched.h"
 #include "stats.h"
@@ -3746,10 +3747,12 @@ void send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
-	if (!set_nr_if_polling(rq->idle))
+	if (!set_nr_if_polling(rq->idle)) {
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	else
+	} else {
 		trace_sched_wake_idle_without_ipi(cpu);
+	}
 }
 
 /*
diff --git a/kernel/smp.c b/kernel/smp.c
index 06a413987a14a..e2ca1e2f31274 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -26,6 +26,10 @@
 #include <linux/sched/debug.h>
 #include <linux/jump_label.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
+#undef CREATE_TRACE_POINTS
+
 #include "smpboot.h"
 #include "sched/smp.h"
 
-- 
2.31.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 3/8] sched, smp: Trace IPIs sent via send_call_function_single_ipi()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

send_call_function_single_ipi() is the thing that sends IPIs at the bottom
of smp_call_function*() via either generic_exec_single() or
smp_call_function_many_cond(). Give it an IPI-related tracepoint.

Note that this ends up tracing any IPI sent via __smp_call_single_queue(),
which covers __ttwu_queue_wakelist() and irq_work_queue_on() "for free".

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 arch/arm/kernel/smp.c   | 3 ---
 arch/arm64/kernel/smp.c | 1 -
 kernel/sched/core.c     | 7 +++++--
 kernel/smp.c            | 4 ++++
 4 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 978db2d96b446..3b280d55c1c40 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -48,9 +48,6 @@
 #include <asm/mach/arch.h>
 #include <asm/mpu.h>
 
-#define CREATE_TRACE_POINTS
-#include <trace/events/ipi.h>
-
 /*
  * as from 2.5, kernels no longer have an init_tasks structure
  * so we need some other way of telling a new secondary core
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index ffc5d76cf6955..937d2623e06ba 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -51,7 +51,6 @@
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
-#define CREATE_TRACE_POINTS
 #include <trace/events/ipi.h>
 
 DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index cb2aa2b54c7a4..02181f8072b5f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -81,6 +81,7 @@
 #include <linux/sched/rseq_api.h>
 #include <trace/events/sched.h>
 #undef CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
 
 #include "sched.h"
 #include "stats.h"
@@ -3746,10 +3747,12 @@ void send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
-	if (!set_nr_if_polling(rq->idle))
+	if (!set_nr_if_polling(rq->idle)) {
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	else
+	} else {
 		trace_sched_wake_idle_without_ipi(cpu);
+	}
 }
 
 /*
diff --git a/kernel/smp.c b/kernel/smp.c
index 06a413987a14a..e2ca1e2f31274 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -26,6 +26,10 @@
 #include <linux/sched/debug.h>
 #include <linux/jump_label.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
+#undef CREATE_TRACE_POINTS
+
 #include "smpboot.h"
 #include "sched/smp.h"
 
-- 
2.31.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 3/8] sched, smp: Trace IPIs sent via send_call_function_single_ipi()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

send_call_function_single_ipi() is the thing that sends IPIs at the bottom
of smp_call_function*() via either generic_exec_single() or
smp_call_function_many_cond(). Give it an IPI-related tracepoint.

Note that this ends up tracing any IPI sent via __smp_call_single_queue(),
which covers __ttwu_queue_wakelist() and irq_work_queue_on() "for free".

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 arch/arm/kernel/smp.c   | 3 ---
 arch/arm64/kernel/smp.c | 1 -
 kernel/sched/core.c     | 7 +++++--
 kernel/smp.c            | 4 ++++
 4 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 978db2d96b446..3b280d55c1c40 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -48,9 +48,6 @@
 #include <asm/mach/arch.h>
 #include <asm/mpu.h>
 
-#define CREATE_TRACE_POINTS
-#include <trace/events/ipi.h>
-
 /*
  * as from 2.5, kernels no longer have an init_tasks structure
  * so we need some other way of telling a new secondary core
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index ffc5d76cf6955..937d2623e06ba 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -51,7 +51,6 @@
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
-#define CREATE_TRACE_POINTS
 #include <trace/events/ipi.h>
 
 DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index cb2aa2b54c7a4..02181f8072b5f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -81,6 +81,7 @@
 #include <linux/sched/rseq_api.h>
 #include <trace/events/sched.h>
 #undef CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
 
 #include "sched.h"
 #include "stats.h"
@@ -3746,10 +3747,12 @@ void send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
-	if (!set_nr_if_polling(rq->idle))
+	if (!set_nr_if_polling(rq->idle)) {
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	else
+	} else {
 		trace_sched_wake_idle_without_ipi(cpu);
+	}
 }
 
 /*
diff --git a/kernel/smp.c b/kernel/smp.c
index 06a413987a14a..e2ca1e2f31274 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -26,6 +26,10 @@
 #include <linux/sched/debug.h>
 #include <linux/jump_label.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
+#undef CREATE_TRACE_POINTS
+
 #include "smpboot.h"
 #include "sched/smp.h"
 
-- 
2.31.1

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
  2022-11-02 18:29 ` Valentin Schneider
                     ` (3 preceding siblings ...)
  (?)
@ 2022-11-02 18:33   ` Valentin Schneider
  -1 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

This simply wraps around the arch function and prepends it with a
tracepoint, similar to send_call_function_single_ipi().

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index e2ca1e2f31274..c4d561cf50d45 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -160,6 +160,13 @@ void __init call_function_init(void)
 	smpcfd_prepare_cpu(smp_processor_id());
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	trace_ipi_send_cpumask(mask, _RET_IP_, func);
+	arch_send_call_function_ipi_mask(mask);
+}
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
@@ -970,7 +977,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		if (nr_cpus == 1)
 			send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
+			send_call_function_ipi_mask(cfd->cpumask_ipi);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Borislav Petkov, Nicholas Piggin, H. Peter Anvin,
	Guo Ren, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

This simply wraps around the arch function and prepends it with a
tracepoint, similar to send_call_function_single_ipi().

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index e2ca1e2f31274..c4d561cf50d45 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -160,6 +160,13 @@ void __init call_function_init(void)
 	smpcfd_prepare_cpu(smp_processor_id());
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	trace_ipi_send_cpumask(mask, _RET_IP_, func);
+	arch_send_call_function_ipi_mask(mask);
+}
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
@@ -970,7 +977,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		if (nr_cpus == 1)
 			send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
+			send_call_function_ipi_mask(cfd->cpumask_ipi);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

This simply wraps around the arch function and prepends it with a
tracepoint, similar to send_call_function_single_ipi().

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index e2ca1e2f31274..c4d561cf50d45 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -160,6 +160,13 @@ void __init call_function_init(void)
 	smpcfd_prepare_cpu(smp_processor_id());
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	trace_ipi_send_cpumask(mask, _RET_IP_, func);
+	arch_send_call_function_ipi_mask(mask);
+}
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
@@ -970,7 +977,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		if (nr_cpus == 1)
 			send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
+			send_call_function_ipi_mask(cfd->cpumask_ipi);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

This simply wraps around the arch function and prepends it with a
tracepoint, similar to send_call_function_single_ipi().

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index e2ca1e2f31274..c4d561cf50d45 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -160,6 +160,13 @@ void __init call_function_init(void)
 	smpcfd_prepare_cpu(smp_processor_id());
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	trace_ipi_send_cpumask(mask, _RET_IP_, func);
+	arch_send_call_function_ipi_mask(mask);
+}
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
@@ -970,7 +977,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		if (nr_cpus == 1)
 			send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
+			send_call_function_ipi_mask(cfd->cpumask_ipi);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

This simply wraps around the arch function and prepends it with a
tracepoint, similar to send_call_function_single_ipi().

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index e2ca1e2f31274..c4d561cf50d45 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -160,6 +160,13 @@ void __init call_function_init(void)
 	smpcfd_prepare_cpu(smp_processor_id());
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	trace_ipi_send_cpumask(mask, _RET_IP_, func);
+	arch_send_call_function_ipi_mask(mask);
+}
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
@@ -970,7 +977,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		if (nr_cpus == 1)
 			send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
+			send_call_function_ipi_mask(cfd->cpumask_ipi);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

This simply wraps around the arch function and prepends it with a
tracepoint, similar to send_call_function_single_ipi().

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index e2ca1e2f31274..c4d561cf50d45 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -160,6 +160,13 @@ void __init call_function_init(void)
 	smpcfd_prepare_cpu(smp_processor_id());
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	trace_ipi_send_cpumask(mask, _RET_IP_, func);
+	arch_send_call_function_ipi_mask(mask);
+}
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
@@ -970,7 +977,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		if (nr_cpus = 1)
 			send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
+			send_call_function_ipi_mask(cfd->cpumask_ipi);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
  2022-11-02 18:29 ` Valentin Schneider
                     ` (3 preceding siblings ...)
  (?)
@ 2022-11-02 18:33   ` Valentin Schneider
  -1 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
self-IPIs.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 7afa40fe5cc43..aec38c294ce68 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -22,6 +22,8 @@
 #include <asm/processor.h>
 #include <linux/kasan.h>
 
+#include <trace/events/ipi.h>
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
@@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
 	 */
 }
 
+static inline void irq_work_raise(struct irq_work *work)
+{
+	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt())
+		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
+				       _RET_IP_,
+				       work->func);
+
+	arch_irq_work_raise();
+}
+
 /* Enqueue on current CPU, work must already be claimed and preempt disabled */
 static void __irq_work_queue_local(struct irq_work *work)
 {
@@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
 
 	/* If the work is "lazy", handle it from next tick if any */
 	if (!lazy_work || tick_nohz_tick_stopped())
-		arch_irq_work_raise();
+		irq_work_raise(work);
 }
 
 /* Enqueue the irq work @work on the current CPU */
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Borislav Petkov, Nicholas Piggin, H. Peter Anvin,
	Guo Ren, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
self-IPIs.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 7afa40fe5cc43..aec38c294ce68 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -22,6 +22,8 @@
 #include <asm/processor.h>
 #include <linux/kasan.h>
 
+#include <trace/events/ipi.h>
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
@@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
 	 */
 }
 
+static inline void irq_work_raise(struct irq_work *work)
+{
+	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt())
+		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
+				       _RET_IP_,
+				       work->func);
+
+	arch_irq_work_raise();
+}
+
 /* Enqueue on current CPU, work must already be claimed and preempt disabled */
 static void __irq_work_queue_local(struct irq_work *work)
 {
@@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
 
 	/* If the work is "lazy", handle it from next tick if any */
 	if (!lazy_work || tick_nohz_tick_stopped())
-		arch_irq_work_raise();
+		irq_work_raise(work);
 }
 
 /* Enqueue the irq work @work on the current CPU */
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
self-IPIs.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 7afa40fe5cc43..aec38c294ce68 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -22,6 +22,8 @@
 #include <asm/processor.h>
 #include <linux/kasan.h>
 
+#include <trace/events/ipi.h>
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
@@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
 	 */
 }
 
+static inline void irq_work_raise(struct irq_work *work)
+{
+	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt())
+		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
+				       _RET_IP_,
+				       work->func);
+
+	arch_irq_work_raise();
+}
+
 /* Enqueue on current CPU, work must already be claimed and preempt disabled */
 static void __irq_work_queue_local(struct irq_work *work)
 {
@@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
 
 	/* If the work is "lazy", handle it from next tick if any */
 	if (!lazy_work || tick_nohz_tick_stopped())
-		arch_irq_work_raise();
+		irq_work_raise(work);
 }
 
 /* Enqueue the irq work @work on the current CPU */
-- 
2.31.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
self-IPIs.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 7afa40fe5cc43..aec38c294ce68 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -22,6 +22,8 @@
 #include <asm/processor.h>
 #include <linux/kasan.h>
 
+#include <trace/events/ipi.h>
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
@@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
 	 */
 }
 
+static inline void irq_work_raise(struct irq_work *work)
+{
+	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt())
+		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
+				       _RET_IP_,
+				       work->func);
+
+	arch_irq_work_raise();
+}
+
 /* Enqueue on current CPU, work must already be claimed and preempt disabled */
 static void __irq_work_queue_local(struct irq_work *work)
 {
@@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
 
 	/* If the work is "lazy", handle it from next tick if any */
 	if (!lazy_work || tick_nohz_tick_stopped())
-		arch_irq_work_raise();
+		irq_work_raise(work);
 }
 
 /* Enqueue the irq work @work on the current CPU */
-- 
2.31.1


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
self-IPIs.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 7afa40fe5cc43..aec38c294ce68 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -22,6 +22,8 @@
 #include <asm/processor.h>
 #include <linux/kasan.h>
 
+#include <trace/events/ipi.h>
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
@@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
 	 */
 }
 
+static inline void irq_work_raise(struct irq_work *work)
+{
+	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt())
+		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
+				       _RET_IP_,
+				       work->func);
+
+	arch_irq_work_raise();
+}
+
 /* Enqueue on current CPU, work must already be claimed and preempt disabled */
 static void __irq_work_queue_local(struct irq_work *work)
 {
@@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
 
 	/* If the work is "lazy", handle it from next tick if any */
 	if (!lazy_work || tick_nohz_tick_stopped())
-		arch_irq_work_raise();
+		irq_work_raise(work);
 }
 
 /* Enqueue the irq work @work on the current CPU */
-- 
2.31.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
self-IPIs.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 7afa40fe5cc43..aec38c294ce68 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -22,6 +22,8 @@
 #include <asm/processor.h>
 #include <linux/kasan.h>
 
+#include <trace/events/ipi.h>
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
@@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
 	 */
 }
 
+static inline void irq_work_raise(struct irq_work *work)
+{
+	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt())
+		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
+				       _RET_IP_,
+				       work->func);
+
+	arch_irq_work_raise();
+}
+
 /* Enqueue on current CPU, work must already be claimed and preempt disabled */
 static void __irq_work_queue_local(struct irq_work *work)
 {
@@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
 
 	/* If the work is "lazy", handle it from next tick if any */
 	if (!lazy_work || tick_nohz_tick_stopped())
-		arch_irq_work_raise();
+		irq_work_raise(work);
 }
 
 /* Enqueue the irq work @work on the current CPU */
-- 
2.31.1

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
  2022-11-02 18:29 ` Valentin Schneider
                     ` (3 preceding siblings ...)
  (?)
@ 2022-11-02 18:33   ` Valentin Schneider
  -1 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Guo Ren, Nicholas Piggin, H. Peter Anvin,
	Borislav Petkov, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

To be able to trace invocations of smp_send_reschedule(), rename the
arch-specific definitions of it to arch_smp_send_reschedule() and wrap it
into an smp_send_reschedule() that contains a tracepoint.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
[csky bits]
Acked-by: Guo Ren <guoren@kernel.org>
---
 arch/alpha/kernel/smp.c          | 2 +-
 arch/arc/kernel/smp.c            | 2 +-
 arch/arm/kernel/smp.c            | 2 +-
 arch/arm64/kernel/smp.c          | 2 +-
 arch/csky/kernel/smp.c           | 2 +-
 arch/hexagon/kernel/smp.c        | 2 +-
 arch/ia64/kernel/smp.c           | 4 ++--
 arch/loongarch/include/asm/smp.h | 2 +-
 arch/mips/include/asm/smp.h      | 2 +-
 arch/openrisc/kernel/smp.c       | 2 +-
 arch/parisc/kernel/smp.c         | 4 ++--
 arch/powerpc/kernel/smp.c        | 4 ++--
 arch/powerpc/kvm/book3s_hv.c     | 1 +
 arch/riscv/kernel/smp.c          | 4 ++--
 arch/s390/kernel/smp.c           | 2 +-
 arch/sh/kernel/smp.c             | 2 +-
 arch/sparc/kernel/smp_32.c       | 2 +-
 arch/sparc/kernel/smp_64.c       | 2 +-
 arch/x86/include/asm/smp.h       | 2 +-
 arch/x86/kvm/svm/svm.c           | 1 +
 arch/x86/kvm/x86.c               | 1 +
 arch/xtensa/kernel/smp.c         | 2 +-
 include/linux/smp.h              | 2 +-
 kernel/smp.c                     | 8 ++++++++
 24 files changed, 35 insertions(+), 24 deletions(-)

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index f4e20f75438f8..38637eb9eebd5 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -562,7 +562,7 @@ handle_ipi(struct pt_regs *regs)
 }
 
 void
-smp_send_reschedule(int cpu)
+arch_smp_send_reschedule(int cpu)
 {
 #ifdef DEBUG_IPI_MSG
 	if (cpu == hard_smp_processor_id())
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index ad93fe6e4b77d..409cfa4675b40 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -292,7 +292,7 @@ static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
 		ipi_send_msg_one(cpu, msg);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	ipi_send_msg_one(cpu, IPI_RESCHEDULE);
 }
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 3b280d55c1c40..f216ac890b6f9 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -745,7 +745,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 937d2623e06ba..8d108edc4a89f 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -976,7 +976,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 4b605aa2e1d65..fd7f81be16dd6 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -140,7 +140,7 @@ void smp_send_stop(void)
 	on_each_cpu(ipi_stop, NULL, 1);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 4ba93e59370c4..4e8bee25b8c68 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -217,7 +217,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index e2cc59db86bc2..ea4f009a232b4 100644
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -220,11 +220,11 @@ kdump_smp_send_init(void)
  * Called with preemption disabled.
  */
 void
-smp_send_reschedule (int cpu)
+arch_smp_send_reschedule (int cpu)
 {
 	ia64_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 /*
  * Called with preemption disabled.
diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
index 71189b28bfb27..3fcca134dfb1b 100644
--- a/arch/loongarch/include/asm/smp.h
+++ b/arch/loongarch/include/asm/smp.h
@@ -83,7 +83,7 @@ extern void show_ipi_list(struct seq_file *p, int prec);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	loongson3_send_ipi_single(cpu, SMP_RESCHEDULE);
 }
diff --git a/arch/mips/include/asm/smp.h b/arch/mips/include/asm/smp.h
index 5d9ff61004ca7..9806e79895d99 100644
--- a/arch/mips/include/asm/smp.h
+++ b/arch/mips/include/asm/smp.h
@@ -66,7 +66,7 @@ extern void calculate_cpu_foreign_map(void);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	extern const struct plat_smp_ops *mp_ops;	/* private */
 
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
index e1419095a6f0a..0a7a059e2dff4 100644
--- a/arch/openrisc/kernel/smp.c
+++ b/arch/openrisc/kernel/smp.c
@@ -173,7 +173,7 @@ void handle_IPI(unsigned int ipi_msg)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 7dbd92cafae38..b7fc859fa87db 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -246,8 +246,8 @@ void kgdb_roundup_cpus(void)
 inline void 
 smp_send_stop(void)	{ send_IPI_allbutself(IPI_CPU_STOP); }
 
-void 
-smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
+void
+arch_smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 
 void
 smp_send_all_nop(void)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 0da6e59161cd4..2f85a757ee792 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -364,12 +364,12 @@ static inline void do_message_pass(int cpu, int msg)
 #endif
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (likely(smp_ops))
 		do_message_pass(cpu, PPC_MSG_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 void arch_send_call_function_single_ipi(int cpu)
 {
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 6ba68dd6190bd..686c80b17627e 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -43,6 +43,7 @@
 #include <linux/compiler.h>
 #include <linux/of.h>
 #include <linux/irqdomain.h>
+#include <linux/smp.h>
 
 #include <asm/ftrace.h>
 #include <asm/reg.h>
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 760a64518c585..213602e89a8b2 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -235,8 +235,8 @@ void smp_send_stop(void)
 			   cpumask_pr_args(cpu_online_mask));
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_single(cpu, IPI_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 0031325ce4bc9..6c4da1e26e568 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -553,7 +553,7 @@ void arch_send_call_function_single_ipi(int cpu)
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 }
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 65924d9ec2459..5cf35a774dc70 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -256,7 +256,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 	       (bogosum / (5000/HZ)) % 100);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	mp_ops->send_ipi(cpu, SMP_MSG_RESCHEDULE);
 }
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index ad8094d955eba..87eaa7719fa27 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -120,7 +120,7 @@ void cpu_panic(void)
 
 struct linux_prom_registers smp_penguin_ctable = { 0 };
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	/*
 	 * CPU model dependent way of implementing IPI generation targeting
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index a55295d1b9244..e5964d1d8b37d 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1430,7 +1430,7 @@ static unsigned long send_cpu_poke(int cpu)
 	return hv_err;
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (cpu == smp_processor_id()) {
 		WARN_ON_ONCE(preemptible());
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index a73bced40e241..5ff5815149bd3 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -99,7 +99,7 @@ static inline void play_dead(void)
 	smp_ops.play_dead();
 }
 
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	smp_ops.smp_send_reschedule(cpu);
 }
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 58f0077d93579..b972c6f8c1791 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -26,6 +26,7 @@
 #include <linux/swap.h>
 #include <linux/rwsem.h>
 #include <linux/cc_platform.h>
+#include <linux/smp.h>
 
 #include <asm/apic.h>
 #include <asm/perf_event.h>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 521b433f978c7..3fbc3fea3e754 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -58,6 +58,7 @@
 #include <linux/mem_encrypt.h>
 #include <linux/entry-kvm.h>
 #include <linux/suspend.h>
+#include <linux/smp.h>
 
 #include <trace/events/kvm.h>
 
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index 4dc109dd6214e..d95907b8e4d38 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -389,7 +389,7 @@ void arch_send_call_function_single_ipi(int cpu)
 	send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/include/linux/smp.h b/include/linux/smp.h
index a80ab58ae3f1d..2f9dc1b7a7fb6 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -125,9 +125,9 @@ extern void smp_send_stop(void);
 /*
  * sends a 'reschedule' event to another CPU:
  */
+extern void arch_smp_send_reschedule(int cpu);
 extern void smp_send_reschedule(int cpu);
 
-
 /*
  * Prepare machine for booting other CPUs.
  */
diff --git a/kernel/smp.c b/kernel/smp.c
index c4d561cf50d45..44fa4b9b1f46b 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
 	arch_send_call_function_ipi_mask(mask);
 }
 
+void smp_send_reschedule(int cpu)
+{
+	/* XXX scheduler_ipi is inline :/ */
+	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
+	arch_smp_send_reschedule(cpu);
+}
+EXPORT_SYMBOL_GPL(smp_send_reschedule);
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Guo Ren, Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

To be able to trace invocations of smp_send_reschedule(), rename the
arch-specific definitions of it to arch_smp_send_reschedule() and wrap it
into an smp_send_reschedule() that contains a tracepoint.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
[csky bits]
Acked-by: Guo Ren <guoren@kernel.org>
---
 arch/alpha/kernel/smp.c          | 2 +-
 arch/arc/kernel/smp.c            | 2 +-
 arch/arm/kernel/smp.c            | 2 +-
 arch/arm64/kernel/smp.c          | 2 +-
 arch/csky/kernel/smp.c           | 2 +-
 arch/hexagon/kernel/smp.c        | 2 +-
 arch/ia64/kernel/smp.c           | 4 ++--
 arch/loongarch/include/asm/smp.h | 2 +-
 arch/mips/include/asm/smp.h      | 2 +-
 arch/openrisc/kernel/smp.c       | 2 +-
 arch/parisc/kernel/smp.c         | 4 ++--
 arch/powerpc/kernel/smp.c        | 4 ++--
 arch/powerpc/kvm/book3s_hv.c     | 1 +
 arch/riscv/kernel/smp.c          | 4 ++--
 arch/s390/kernel/smp.c           | 2 +-
 arch/sh/kernel/smp.c             | 2 +-
 arch/sparc/kernel/smp_32.c       | 2 +-
 arch/sparc/kernel/smp_64.c       | 2 +-
 arch/x86/include/asm/smp.h       | 2 +-
 arch/x86/kvm/svm/svm.c           | 1 +
 arch/x86/kvm/x86.c               | 1 +
 arch/xtensa/kernel/smp.c         | 2 +-
 include/linux/smp.h              | 2 +-
 kernel/smp.c                     | 8 ++++++++
 24 files changed, 35 insertions(+), 24 deletions(-)

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index f4e20f75438f8..38637eb9eebd5 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -562,7 +562,7 @@ handle_ipi(struct pt_regs *regs)
 }
 
 void
-smp_send_reschedule(int cpu)
+arch_smp_send_reschedule(int cpu)
 {
 #ifdef DEBUG_IPI_MSG
 	if (cpu == hard_smp_processor_id())
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index ad93fe6e4b77d..409cfa4675b40 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -292,7 +292,7 @@ static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
 		ipi_send_msg_one(cpu, msg);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	ipi_send_msg_one(cpu, IPI_RESCHEDULE);
 }
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 3b280d55c1c40..f216ac890b6f9 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -745,7 +745,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 937d2623e06ba..8d108edc4a89f 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -976,7 +976,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 4b605aa2e1d65..fd7f81be16dd6 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -140,7 +140,7 @@ void smp_send_stop(void)
 	on_each_cpu(ipi_stop, NULL, 1);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 4ba93e59370c4..4e8bee25b8c68 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -217,7 +217,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index e2cc59db86bc2..ea4f009a232b4 100644
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -220,11 +220,11 @@ kdump_smp_send_init(void)
  * Called with preemption disabled.
  */
 void
-smp_send_reschedule (int cpu)
+arch_smp_send_reschedule (int cpu)
 {
 	ia64_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 /*
  * Called with preemption disabled.
diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
index 71189b28bfb27..3fcca134dfb1b 100644
--- a/arch/loongarch/include/asm/smp.h
+++ b/arch/loongarch/include/asm/smp.h
@@ -83,7 +83,7 @@ extern void show_ipi_list(struct seq_file *p, int prec);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	loongson3_send_ipi_single(cpu, SMP_RESCHEDULE);
 }
diff --git a/arch/mips/include/asm/smp.h b/arch/mips/include/asm/smp.h
index 5d9ff61004ca7..9806e79895d99 100644
--- a/arch/mips/include/asm/smp.h
+++ b/arch/mips/include/asm/smp.h
@@ -66,7 +66,7 @@ extern void calculate_cpu_foreign_map(void);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	extern const struct plat_smp_ops *mp_ops;	/* private */
 
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
index e1419095a6f0a..0a7a059e2dff4 100644
--- a/arch/openrisc/kernel/smp.c
+++ b/arch/openrisc/kernel/smp.c
@@ -173,7 +173,7 @@ void handle_IPI(unsigned int ipi_msg)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 7dbd92cafae38..b7fc859fa87db 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -246,8 +246,8 @@ void kgdb_roundup_cpus(void)
 inline void 
 smp_send_stop(void)	{ send_IPI_allbutself(IPI_CPU_STOP); }
 
-void 
-smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
+void
+arch_smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 
 void
 smp_send_all_nop(void)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 0da6e59161cd4..2f85a757ee792 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -364,12 +364,12 @@ static inline void do_message_pass(int cpu, int msg)
 #endif
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (likely(smp_ops))
 		do_message_pass(cpu, PPC_MSG_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 void arch_send_call_function_single_ipi(int cpu)
 {
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 6ba68dd6190bd..686c80b17627e 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -43,6 +43,7 @@
 #include <linux/compiler.h>
 #include <linux/of.h>
 #include <linux/irqdomain.h>
+#include <linux/smp.h>
 
 #include <asm/ftrace.h>
 #include <asm/reg.h>
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 760a64518c585..213602e89a8b2 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -235,8 +235,8 @@ void smp_send_stop(void)
 			   cpumask_pr_args(cpu_online_mask));
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_single(cpu, IPI_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 0031325ce4bc9..6c4da1e26e568 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -553,7 +553,7 @@ void arch_send_call_function_single_ipi(int cpu)
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 }
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 65924d9ec2459..5cf35a774dc70 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -256,7 +256,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 	       (bogosum / (5000/HZ)) % 100);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	mp_ops->send_ipi(cpu, SMP_MSG_RESCHEDULE);
 }
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index ad8094d955eba..87eaa7719fa27 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -120,7 +120,7 @@ void cpu_panic(void)
 
 struct linux_prom_registers smp_penguin_ctable = { 0 };
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	/*
 	 * CPU model dependent way of implementing IPI generation targeting
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index a55295d1b9244..e5964d1d8b37d 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1430,7 +1430,7 @@ static unsigned long send_cpu_poke(int cpu)
 	return hv_err;
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (cpu == smp_processor_id()) {
 		WARN_ON_ONCE(preemptible());
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index a73bced40e241..5ff5815149bd3 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -99,7 +99,7 @@ static inline void play_dead(void)
 	smp_ops.play_dead();
 }
 
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	smp_ops.smp_send_reschedule(cpu);
 }
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 58f0077d93579..b972c6f8c1791 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -26,6 +26,7 @@
 #include <linux/swap.h>
 #include <linux/rwsem.h>
 #include <linux/cc_platform.h>
+#include <linux/smp.h>
 
 #include <asm/apic.h>
 #include <asm/perf_event.h>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 521b433f978c7..3fbc3fea3e754 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -58,6 +58,7 @@
 #include <linux/mem_encrypt.h>
 #include <linux/entry-kvm.h>
 #include <linux/suspend.h>
+#include <linux/smp.h>
 
 #include <trace/events/kvm.h>
 
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index 4dc109dd6214e..d95907b8e4d38 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -389,7 +389,7 @@ void arch_send_call_function_single_ipi(int cpu)
 	send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/include/linux/smp.h b/include/linux/smp.h
index a80ab58ae3f1d..2f9dc1b7a7fb6 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -125,9 +125,9 @@ extern void smp_send_stop(void);
 /*
  * sends a 'reschedule' event to another CPU:
  */
+extern void arch_smp_send_reschedule(int cpu);
 extern void smp_send_reschedule(int cpu);
 
-
 /*
  * Prepare machine for booting other CPUs.
  */
diff --git a/kernel/smp.c b/kernel/smp.c
index c4d561cf50d45..44fa4b9b1f46b 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
 	arch_send_call_function_ipi_mask(mask);
 }
 
+void smp_send_reschedule(int cpu)
+{
+	/* XXX scheduler_ipi is inline :/ */
+	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
+	arch_smp_send_reschedule(cpu);
+}
+EXPORT_SYMBOL_GPL(smp_send_reschedule);
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Guo Ren, Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

To be able to trace invocations of smp_send_reschedule(), rename the
arch-specific definitions of it to arch_smp_send_reschedule() and wrap it
into an smp_send_reschedule() that contains a tracepoint.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
[csky bits]
Acked-by: Guo Ren <guoren@kernel.org>
---
 arch/alpha/kernel/smp.c          | 2 +-
 arch/arc/kernel/smp.c            | 2 +-
 arch/arm/kernel/smp.c            | 2 +-
 arch/arm64/kernel/smp.c          | 2 +-
 arch/csky/kernel/smp.c           | 2 +-
 arch/hexagon/kernel/smp.c        | 2 +-
 arch/ia64/kernel/smp.c           | 4 ++--
 arch/loongarch/include/asm/smp.h | 2 +-
 arch/mips/include/asm/smp.h      | 2 +-
 arch/openrisc/kernel/smp.c       | 2 +-
 arch/parisc/kernel/smp.c         | 4 ++--
 arch/powerpc/kernel/smp.c        | 4 ++--
 arch/powerpc/kvm/book3s_hv.c     | 1 +
 arch/riscv/kernel/smp.c          | 4 ++--
 arch/s390/kernel/smp.c           | 2 +-
 arch/sh/kernel/smp.c             | 2 +-
 arch/sparc/kernel/smp_32.c       | 2 +-
 arch/sparc/kernel/smp_64.c       | 2 +-
 arch/x86/include/asm/smp.h       | 2 +-
 arch/x86/kvm/svm/svm.c           | 1 +
 arch/x86/kvm/x86.c               | 1 +
 arch/xtensa/kernel/smp.c         | 2 +-
 include/linux/smp.h              | 2 +-
 kernel/smp.c                     | 8 ++++++++
 24 files changed, 35 insertions(+), 24 deletions(-)

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index f4e20f75438f8..38637eb9eebd5 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -562,7 +562,7 @@ handle_ipi(struct pt_regs *regs)
 }
 
 void
-smp_send_reschedule(int cpu)
+arch_smp_send_reschedule(int cpu)
 {
 #ifdef DEBUG_IPI_MSG
 	if (cpu == hard_smp_processor_id())
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index ad93fe6e4b77d..409cfa4675b40 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -292,7 +292,7 @@ static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
 		ipi_send_msg_one(cpu, msg);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	ipi_send_msg_one(cpu, IPI_RESCHEDULE);
 }
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 3b280d55c1c40..f216ac890b6f9 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -745,7 +745,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 937d2623e06ba..8d108edc4a89f 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -976,7 +976,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 4b605aa2e1d65..fd7f81be16dd6 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -140,7 +140,7 @@ void smp_send_stop(void)
 	on_each_cpu(ipi_stop, NULL, 1);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 4ba93e59370c4..4e8bee25b8c68 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -217,7 +217,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index e2cc59db86bc2..ea4f009a232b4 100644
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -220,11 +220,11 @@ kdump_smp_send_init(void)
  * Called with preemption disabled.
  */
 void
-smp_send_reschedule (int cpu)
+arch_smp_send_reschedule (int cpu)
 {
 	ia64_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 /*
  * Called with preemption disabled.
diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
index 71189b28bfb27..3fcca134dfb1b 100644
--- a/arch/loongarch/include/asm/smp.h
+++ b/arch/loongarch/include/asm/smp.h
@@ -83,7 +83,7 @@ extern void show_ipi_list(struct seq_file *p, int prec);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	loongson3_send_ipi_single(cpu, SMP_RESCHEDULE);
 }
diff --git a/arch/mips/include/asm/smp.h b/arch/mips/include/asm/smp.h
index 5d9ff61004ca7..9806e79895d99 100644
--- a/arch/mips/include/asm/smp.h
+++ b/arch/mips/include/asm/smp.h
@@ -66,7 +66,7 @@ extern void calculate_cpu_foreign_map(void);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	extern const struct plat_smp_ops *mp_ops;	/* private */
 
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
index e1419095a6f0a..0a7a059e2dff4 100644
--- a/arch/openrisc/kernel/smp.c
+++ b/arch/openrisc/kernel/smp.c
@@ -173,7 +173,7 @@ void handle_IPI(unsigned int ipi_msg)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 7dbd92cafae38..b7fc859fa87db 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -246,8 +246,8 @@ void kgdb_roundup_cpus(void)
 inline void 
 smp_send_stop(void)	{ send_IPI_allbutself(IPI_CPU_STOP); }
 
-void 
-smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
+void
+arch_smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 
 void
 smp_send_all_nop(void)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 0da6e59161cd4..2f85a757ee792 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -364,12 +364,12 @@ static inline void do_message_pass(int cpu, int msg)
 #endif
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (likely(smp_ops))
 		do_message_pass(cpu, PPC_MSG_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 void arch_send_call_function_single_ipi(int cpu)
 {
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 6ba68dd6190bd..686c80b17627e 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -43,6 +43,7 @@
 #include <linux/compiler.h>
 #include <linux/of.h>
 #include <linux/irqdomain.h>
+#include <linux/smp.h>
 
 #include <asm/ftrace.h>
 #include <asm/reg.h>
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 760a64518c585..213602e89a8b2 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -235,8 +235,8 @@ void smp_send_stop(void)
 			   cpumask_pr_args(cpu_online_mask));
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_single(cpu, IPI_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 0031325ce4bc9..6c4da1e26e568 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -553,7 +553,7 @@ void arch_send_call_function_single_ipi(int cpu)
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 }
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 65924d9ec2459..5cf35a774dc70 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -256,7 +256,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 	       (bogosum / (5000/HZ)) % 100);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	mp_ops->send_ipi(cpu, SMP_MSG_RESCHEDULE);
 }
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index ad8094d955eba..87eaa7719fa27 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -120,7 +120,7 @@ void cpu_panic(void)
 
 struct linux_prom_registers smp_penguin_ctable = { 0 };
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	/*
 	 * CPU model dependent way of implementing IPI generation targeting
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index a55295d1b9244..e5964d1d8b37d 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1430,7 +1430,7 @@ static unsigned long send_cpu_poke(int cpu)
 	return hv_err;
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (cpu == smp_processor_id()) {
 		WARN_ON_ONCE(preemptible());
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index a73bced40e241..5ff5815149bd3 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -99,7 +99,7 @@ static inline void play_dead(void)
 	smp_ops.play_dead();
 }
 
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	smp_ops.smp_send_reschedule(cpu);
 }
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 58f0077d93579..b972c6f8c1791 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -26,6 +26,7 @@
 #include <linux/swap.h>
 #include <linux/rwsem.h>
 #include <linux/cc_platform.h>
+#include <linux/smp.h>
 
 #include <asm/apic.h>
 #include <asm/perf_event.h>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 521b433f978c7..3fbc3fea3e754 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -58,6 +58,7 @@
 #include <linux/mem_encrypt.h>
 #include <linux/entry-kvm.h>
 #include <linux/suspend.h>
+#include <linux/smp.h>
 
 #include <trace/events/kvm.h>
 
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index 4dc109dd6214e..d95907b8e4d38 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -389,7 +389,7 @@ void arch_send_call_function_single_ipi(int cpu)
 	send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/include/linux/smp.h b/include/linux/smp.h
index a80ab58ae3f1d..2f9dc1b7a7fb6 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -125,9 +125,9 @@ extern void smp_send_stop(void);
 /*
  * sends a 'reschedule' event to another CPU:
  */
+extern void arch_smp_send_reschedule(int cpu);
 extern void smp_send_reschedule(int cpu);
 
-
 /*
  * Prepare machine for booting other CPUs.
  */
diff --git a/kernel/smp.c b/kernel/smp.c
index c4d561cf50d45..44fa4b9b1f46b 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
 	arch_send_call_function_ipi_mask(mask);
 }
 
+void smp_send_reschedule(int cpu)
+{
+	/* XXX scheduler_ipi is inline :/ */
+	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
+	arch_smp_send_reschedule(cpu);
+}
+EXPORT_SYMBOL_GPL(smp_send_reschedule);
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
-- 
2.31.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Guo Ren, Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

To be able to trace invocations of smp_send_reschedule(), rename the
arch-specific definitions of it to arch_smp_send_reschedule() and wrap it
into an smp_send_reschedule() that contains a tracepoint.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
[csky bits]
Acked-by: Guo Ren <guoren@kernel.org>
---
 arch/alpha/kernel/smp.c          | 2 +-
 arch/arc/kernel/smp.c            | 2 +-
 arch/arm/kernel/smp.c            | 2 +-
 arch/arm64/kernel/smp.c          | 2 +-
 arch/csky/kernel/smp.c           | 2 +-
 arch/hexagon/kernel/smp.c        | 2 +-
 arch/ia64/kernel/smp.c           | 4 ++--
 arch/loongarch/include/asm/smp.h | 2 +-
 arch/mips/include/asm/smp.h      | 2 +-
 arch/openrisc/kernel/smp.c       | 2 +-
 arch/parisc/kernel/smp.c         | 4 ++--
 arch/powerpc/kernel/smp.c        | 4 ++--
 arch/powerpc/kvm/book3s_hv.c     | 1 +
 arch/riscv/kernel/smp.c          | 4 ++--
 arch/s390/kernel/smp.c           | 2 +-
 arch/sh/kernel/smp.c             | 2 +-
 arch/sparc/kernel/smp_32.c       | 2 +-
 arch/sparc/kernel/smp_64.c       | 2 +-
 arch/x86/include/asm/smp.h       | 2 +-
 arch/x86/kvm/svm/svm.c           | 1 +
 arch/x86/kvm/x86.c               | 1 +
 arch/xtensa/kernel/smp.c         | 2 +-
 include/linux/smp.h              | 2 +-
 kernel/smp.c                     | 8 ++++++++
 24 files changed, 35 insertions(+), 24 deletions(-)

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index f4e20f75438f8..38637eb9eebd5 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -562,7 +562,7 @@ handle_ipi(struct pt_regs *regs)
 }
 
 void
-smp_send_reschedule(int cpu)
+arch_smp_send_reschedule(int cpu)
 {
 #ifdef DEBUG_IPI_MSG
 	if (cpu == hard_smp_processor_id())
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index ad93fe6e4b77d..409cfa4675b40 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -292,7 +292,7 @@ static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
 		ipi_send_msg_one(cpu, msg);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	ipi_send_msg_one(cpu, IPI_RESCHEDULE);
 }
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 3b280d55c1c40..f216ac890b6f9 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -745,7 +745,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 937d2623e06ba..8d108edc4a89f 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -976,7 +976,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 4b605aa2e1d65..fd7f81be16dd6 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -140,7 +140,7 @@ void smp_send_stop(void)
 	on_each_cpu(ipi_stop, NULL, 1);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 4ba93e59370c4..4e8bee25b8c68 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -217,7 +217,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index e2cc59db86bc2..ea4f009a232b4 100644
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -220,11 +220,11 @@ kdump_smp_send_init(void)
  * Called with preemption disabled.
  */
 void
-smp_send_reschedule (int cpu)
+arch_smp_send_reschedule (int cpu)
 {
 	ia64_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 /*
  * Called with preemption disabled.
diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
index 71189b28bfb27..3fcca134dfb1b 100644
--- a/arch/loongarch/include/asm/smp.h
+++ b/arch/loongarch/include/asm/smp.h
@@ -83,7 +83,7 @@ extern void show_ipi_list(struct seq_file *p, int prec);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	loongson3_send_ipi_single(cpu, SMP_RESCHEDULE);
 }
diff --git a/arch/mips/include/asm/smp.h b/arch/mips/include/asm/smp.h
index 5d9ff61004ca7..9806e79895d99 100644
--- a/arch/mips/include/asm/smp.h
+++ b/arch/mips/include/asm/smp.h
@@ -66,7 +66,7 @@ extern void calculate_cpu_foreign_map(void);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	extern const struct plat_smp_ops *mp_ops;	/* private */
 
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
index e1419095a6f0a..0a7a059e2dff4 100644
--- a/arch/openrisc/kernel/smp.c
+++ b/arch/openrisc/kernel/smp.c
@@ -173,7 +173,7 @@ void handle_IPI(unsigned int ipi_msg)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 7dbd92cafae38..b7fc859fa87db 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -246,8 +246,8 @@ void kgdb_roundup_cpus(void)
 inline void 
 smp_send_stop(void)	{ send_IPI_allbutself(IPI_CPU_STOP); }
 
-void 
-smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
+void
+arch_smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 
 void
 smp_send_all_nop(void)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 0da6e59161cd4..2f85a757ee792 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -364,12 +364,12 @@ static inline void do_message_pass(int cpu, int msg)
 #endif
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (likely(smp_ops))
 		do_message_pass(cpu, PPC_MSG_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 void arch_send_call_function_single_ipi(int cpu)
 {
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 6ba68dd6190bd..686c80b17627e 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -43,6 +43,7 @@
 #include <linux/compiler.h>
 #include <linux/of.h>
 #include <linux/irqdomain.h>
+#include <linux/smp.h>
 
 #include <asm/ftrace.h>
 #include <asm/reg.h>
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 760a64518c585..213602e89a8b2 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -235,8 +235,8 @@ void smp_send_stop(void)
 			   cpumask_pr_args(cpu_online_mask));
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_single(cpu, IPI_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 0031325ce4bc9..6c4da1e26e568 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -553,7 +553,7 @@ void arch_send_call_function_single_ipi(int cpu)
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 }
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 65924d9ec2459..5cf35a774dc70 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -256,7 +256,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 	       (bogosum / (5000/HZ)) % 100);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	mp_ops->send_ipi(cpu, SMP_MSG_RESCHEDULE);
 }
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index ad8094d955eba..87eaa7719fa27 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -120,7 +120,7 @@ void cpu_panic(void)
 
 struct linux_prom_registers smp_penguin_ctable = { 0 };
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	/*
 	 * CPU model dependent way of implementing IPI generation targeting
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index a55295d1b9244..e5964d1d8b37d 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1430,7 +1430,7 @@ static unsigned long send_cpu_poke(int cpu)
 	return hv_err;
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (cpu == smp_processor_id()) {
 		WARN_ON_ONCE(preemptible());
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index a73bced40e241..5ff5815149bd3 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -99,7 +99,7 @@ static inline void play_dead(void)
 	smp_ops.play_dead();
 }
 
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	smp_ops.smp_send_reschedule(cpu);
 }
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 58f0077d93579..b972c6f8c1791 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -26,6 +26,7 @@
 #include <linux/swap.h>
 #include <linux/rwsem.h>
 #include <linux/cc_platform.h>
+#include <linux/smp.h>
 
 #include <asm/apic.h>
 #include <asm/perf_event.h>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 521b433f978c7..3fbc3fea3e754 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -58,6 +58,7 @@
 #include <linux/mem_encrypt.h>
 #include <linux/entry-kvm.h>
 #include <linux/suspend.h>
+#include <linux/smp.h>
 
 #include <trace/events/kvm.h>
 
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index 4dc109dd6214e..d95907b8e4d38 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -389,7 +389,7 @@ void arch_send_call_function_single_ipi(int cpu)
 	send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/include/linux/smp.h b/include/linux/smp.h
index a80ab58ae3f1d..2f9dc1b7a7fb6 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -125,9 +125,9 @@ extern void smp_send_stop(void);
 /*
  * sends a 'reschedule' event to another CPU:
  */
+extern void arch_smp_send_reschedule(int cpu);
 extern void smp_send_reschedule(int cpu);
 
-
 /*
  * Prepare machine for booting other CPUs.
  */
diff --git a/kernel/smp.c b/kernel/smp.c
index c4d561cf50d45..44fa4b9b1f46b 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
 	arch_send_call_function_ipi_mask(mask);
 }
 
+void smp_send_reschedule(int cpu)
+{
+	/* XXX scheduler_ipi is inline :/ */
+	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
+	arch_smp_send_reschedule(cpu);
+}
+EXPORT_SYMBOL_GPL(smp_send_reschedule);
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
-- 
2.31.1


_______________________________________________
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linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Guo Ren, Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

To be able to trace invocations of smp_send_reschedule(), rename the
arch-specific definitions of it to arch_smp_send_reschedule() and wrap it
into an smp_send_reschedule() that contains a tracepoint.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
[csky bits]
Acked-by: Guo Ren <guoren@kernel.org>
---
 arch/alpha/kernel/smp.c          | 2 +-
 arch/arc/kernel/smp.c            | 2 +-
 arch/arm/kernel/smp.c            | 2 +-
 arch/arm64/kernel/smp.c          | 2 +-
 arch/csky/kernel/smp.c           | 2 +-
 arch/hexagon/kernel/smp.c        | 2 +-
 arch/ia64/kernel/smp.c           | 4 ++--
 arch/loongarch/include/asm/smp.h | 2 +-
 arch/mips/include/asm/smp.h      | 2 +-
 arch/openrisc/kernel/smp.c       | 2 +-
 arch/parisc/kernel/smp.c         | 4 ++--
 arch/powerpc/kernel/smp.c        | 4 ++--
 arch/powerpc/kvm/book3s_hv.c     | 1 +
 arch/riscv/kernel/smp.c          | 4 ++--
 arch/s390/kernel/smp.c           | 2 +-
 arch/sh/kernel/smp.c             | 2 +-
 arch/sparc/kernel/smp_32.c       | 2 +-
 arch/sparc/kernel/smp_64.c       | 2 +-
 arch/x86/include/asm/smp.h       | 2 +-
 arch/x86/kvm/svm/svm.c           | 1 +
 arch/x86/kvm/x86.c               | 1 +
 arch/xtensa/kernel/smp.c         | 2 +-
 include/linux/smp.h              | 2 +-
 kernel/smp.c                     | 8 ++++++++
 24 files changed, 35 insertions(+), 24 deletions(-)

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index f4e20f75438f8..38637eb9eebd5 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -562,7 +562,7 @@ handle_ipi(struct pt_regs *regs)
 }
 
 void
-smp_send_reschedule(int cpu)
+arch_smp_send_reschedule(int cpu)
 {
 #ifdef DEBUG_IPI_MSG
 	if (cpu == hard_smp_processor_id())
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index ad93fe6e4b77d..409cfa4675b40 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -292,7 +292,7 @@ static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
 		ipi_send_msg_one(cpu, msg);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	ipi_send_msg_one(cpu, IPI_RESCHEDULE);
 }
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 3b280d55c1c40..f216ac890b6f9 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -745,7 +745,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 937d2623e06ba..8d108edc4a89f 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -976,7 +976,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 4b605aa2e1d65..fd7f81be16dd6 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -140,7 +140,7 @@ void smp_send_stop(void)
 	on_each_cpu(ipi_stop, NULL, 1);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 4ba93e59370c4..4e8bee25b8c68 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -217,7 +217,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index e2cc59db86bc2..ea4f009a232b4 100644
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -220,11 +220,11 @@ kdump_smp_send_init(void)
  * Called with preemption disabled.
  */
 void
-smp_send_reschedule (int cpu)
+arch_smp_send_reschedule (int cpu)
 {
 	ia64_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 /*
  * Called with preemption disabled.
diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
index 71189b28bfb27..3fcca134dfb1b 100644
--- a/arch/loongarch/include/asm/smp.h
+++ b/arch/loongarch/include/asm/smp.h
@@ -83,7 +83,7 @@ extern void show_ipi_list(struct seq_file *p, int prec);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	loongson3_send_ipi_single(cpu, SMP_RESCHEDULE);
 }
diff --git a/arch/mips/include/asm/smp.h b/arch/mips/include/asm/smp.h
index 5d9ff61004ca7..9806e79895d99 100644
--- a/arch/mips/include/asm/smp.h
+++ b/arch/mips/include/asm/smp.h
@@ -66,7 +66,7 @@ extern void calculate_cpu_foreign_map(void);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	extern const struct plat_smp_ops *mp_ops;	/* private */
 
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
index e1419095a6f0a..0a7a059e2dff4 100644
--- a/arch/openrisc/kernel/smp.c
+++ b/arch/openrisc/kernel/smp.c
@@ -173,7 +173,7 @@ void handle_IPI(unsigned int ipi_msg)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 7dbd92cafae38..b7fc859fa87db 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -246,8 +246,8 @@ void kgdb_roundup_cpus(void)
 inline void 
 smp_send_stop(void)	{ send_IPI_allbutself(IPI_CPU_STOP); }
 
-void 
-smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
+void
+arch_smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 
 void
 smp_send_all_nop(void)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 0da6e59161cd4..2f85a757ee792 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -364,12 +364,12 @@ static inline void do_message_pass(int cpu, int msg)
 #endif
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (likely(smp_ops))
 		do_message_pass(cpu, PPC_MSG_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 void arch_send_call_function_single_ipi(int cpu)
 {
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 6ba68dd6190bd..686c80b17627e 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -43,6 +43,7 @@
 #include <linux/compiler.h>
 #include <linux/of.h>
 #include <linux/irqdomain.h>
+#include <linux/smp.h>
 
 #include <asm/ftrace.h>
 #include <asm/reg.h>
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 760a64518c585..213602e89a8b2 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -235,8 +235,8 @@ void smp_send_stop(void)
 			   cpumask_pr_args(cpu_online_mask));
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_single(cpu, IPI_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 0031325ce4bc9..6c4da1e26e568 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -553,7 +553,7 @@ void arch_send_call_function_single_ipi(int cpu)
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 }
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 65924d9ec2459..5cf35a774dc70 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -256,7 +256,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 	       (bogosum / (5000/HZ)) % 100);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	mp_ops->send_ipi(cpu, SMP_MSG_RESCHEDULE);
 }
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index ad8094d955eba..87eaa7719fa27 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -120,7 +120,7 @@ void cpu_panic(void)
 
 struct linux_prom_registers smp_penguin_ctable = { 0 };
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	/*
 	 * CPU model dependent way of implementing IPI generation targeting
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index a55295d1b9244..e5964d1d8b37d 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1430,7 +1430,7 @@ static unsigned long send_cpu_poke(int cpu)
 	return hv_err;
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (cpu == smp_processor_id()) {
 		WARN_ON_ONCE(preemptible());
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index a73bced40e241..5ff5815149bd3 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -99,7 +99,7 @@ static inline void play_dead(void)
 	smp_ops.play_dead();
 }
 
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	smp_ops.smp_send_reschedule(cpu);
 }
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 58f0077d93579..b972c6f8c1791 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -26,6 +26,7 @@
 #include <linux/swap.h>
 #include <linux/rwsem.h>
 #include <linux/cc_platform.h>
+#include <linux/smp.h>
 
 #include <asm/apic.h>
 #include <asm/perf_event.h>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 521b433f978c7..3fbc3fea3e754 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -58,6 +58,7 @@
 #include <linux/mem_encrypt.h>
 #include <linux/entry-kvm.h>
 #include <linux/suspend.h>
+#include <linux/smp.h>
 
 #include <trace/events/kvm.h>
 
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index 4dc109dd6214e..d95907b8e4d38 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -389,7 +389,7 @@ void arch_send_call_function_single_ipi(int cpu)
 	send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/include/linux/smp.h b/include/linux/smp.h
index a80ab58ae3f1d..2f9dc1b7a7fb6 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -125,9 +125,9 @@ extern void smp_send_stop(void);
 /*
  * sends a 'reschedule' event to another CPU:
  */
+extern void arch_smp_send_reschedule(int cpu);
 extern void smp_send_reschedule(int cpu);
 
-
 /*
  * Prepare machine for booting other CPUs.
  */
diff --git a/kernel/smp.c b/kernel/smp.c
index c4d561cf50d45..44fa4b9b1f46b 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
 	arch_send_call_function_ipi_mask(mask);
 }
 
+void smp_send_reschedule(int cpu)
+{
+	/* XXX scheduler_ipi is inline :/ */
+	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
+	arch_smp_send_reschedule(cpu);
+}
+EXPORT_SYMBOL_GPL(smp_send_reschedule);
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
-- 
2.31.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Guo Ren, Nicholas Piggin, H. Peter Anvin,
	Borislav Petkov, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

To be able to trace invocations of smp_send_reschedule(), rename the
arch-specific definitions of it to arch_smp_send_reschedule() and wrap it
into an smp_send_reschedule() that contains a tracepoint.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
[csky bits]
Acked-by: Guo Ren <guoren@kernel.org>
---
 arch/alpha/kernel/smp.c          | 2 +-
 arch/arc/kernel/smp.c            | 2 +-
 arch/arm/kernel/smp.c            | 2 +-
 arch/arm64/kernel/smp.c          | 2 +-
 arch/csky/kernel/smp.c           | 2 +-
 arch/hexagon/kernel/smp.c        | 2 +-
 arch/ia64/kernel/smp.c           | 4 ++--
 arch/loongarch/include/asm/smp.h | 2 +-
 arch/mips/include/asm/smp.h      | 2 +-
 arch/openrisc/kernel/smp.c       | 2 +-
 arch/parisc/kernel/smp.c         | 4 ++--
 arch/powerpc/kernel/smp.c        | 4 ++--
 arch/powerpc/kvm/book3s_hv.c     | 1 +
 arch/riscv/kernel/smp.c          | 4 ++--
 arch/s390/kernel/smp.c           | 2 +-
 arch/sh/kernel/smp.c             | 2 +-
 arch/sparc/kernel/smp_32.c       | 2 +-
 arch/sparc/kernel/smp_64.c       | 2 +-
 arch/x86/include/asm/smp.h       | 2 +-
 arch/x86/kvm/svm/svm.c           | 1 +
 arch/x86/kvm/x86.c               | 1 +
 arch/xtensa/kernel/smp.c         | 2 +-
 include/linux/smp.h              | 2 +-
 kernel/smp.c                     | 8 ++++++++
 24 files changed, 35 insertions(+), 24 deletions(-)

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index f4e20f75438f8..38637eb9eebd5 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -562,7 +562,7 @@ handle_ipi(struct pt_regs *regs)
 }
 
 void
-smp_send_reschedule(int cpu)
+arch_smp_send_reschedule(int cpu)
 {
 #ifdef DEBUG_IPI_MSG
 	if (cpu = hard_smp_processor_id())
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index ad93fe6e4b77d..409cfa4675b40 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -292,7 +292,7 @@ static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
 		ipi_send_msg_one(cpu, msg);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	ipi_send_msg_one(cpu, IPI_RESCHEDULE);
 }
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 3b280d55c1c40..f216ac890b6f9 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -745,7 +745,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 937d2623e06ba..8d108edc4a89f 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -976,7 +976,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 4b605aa2e1d65..fd7f81be16dd6 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -140,7 +140,7 @@ void smp_send_stop(void)
 	on_each_cpu(ipi_stop, NULL, 1);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 4ba93e59370c4..4e8bee25b8c68 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -217,7 +217,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index e2cc59db86bc2..ea4f009a232b4 100644
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -220,11 +220,11 @@ kdump_smp_send_init(void)
  * Called with preemption disabled.
  */
 void
-smp_send_reschedule (int cpu)
+arch_smp_send_reschedule (int cpu)
 {
 	ia64_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 /*
  * Called with preemption disabled.
diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
index 71189b28bfb27..3fcca134dfb1b 100644
--- a/arch/loongarch/include/asm/smp.h
+++ b/arch/loongarch/include/asm/smp.h
@@ -83,7 +83,7 @@ extern void show_ipi_list(struct seq_file *p, int prec);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	loongson3_send_ipi_single(cpu, SMP_RESCHEDULE);
 }
diff --git a/arch/mips/include/asm/smp.h b/arch/mips/include/asm/smp.h
index 5d9ff61004ca7..9806e79895d99 100644
--- a/arch/mips/include/asm/smp.h
+++ b/arch/mips/include/asm/smp.h
@@ -66,7 +66,7 @@ extern void calculate_cpu_foreign_map(void);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	extern const struct plat_smp_ops *mp_ops;	/* private */
 
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
index e1419095a6f0a..0a7a059e2dff4 100644
--- a/arch/openrisc/kernel/smp.c
+++ b/arch/openrisc/kernel/smp.c
@@ -173,7 +173,7 @@ void handle_IPI(unsigned int ipi_msg)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 7dbd92cafae38..b7fc859fa87db 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -246,8 +246,8 @@ void kgdb_roundup_cpus(void)
 inline void 
 smp_send_stop(void)	{ send_IPI_allbutself(IPI_CPU_STOP); }
 
-void 
-smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
+void
+arch_smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 
 void
 smp_send_all_nop(void)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 0da6e59161cd4..2f85a757ee792 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -364,12 +364,12 @@ static inline void do_message_pass(int cpu, int msg)
 #endif
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (likely(smp_ops))
 		do_message_pass(cpu, PPC_MSG_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 void arch_send_call_function_single_ipi(int cpu)
 {
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 6ba68dd6190bd..686c80b17627e 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -43,6 +43,7 @@
 #include <linux/compiler.h>
 #include <linux/of.h>
 #include <linux/irqdomain.h>
+#include <linux/smp.h>
 
 #include <asm/ftrace.h>
 #include <asm/reg.h>
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 760a64518c585..213602e89a8b2 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -235,8 +235,8 @@ void smp_send_stop(void)
 			   cpumask_pr_args(cpu_online_mask));
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_single(cpu, IPI_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 0031325ce4bc9..6c4da1e26e568 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -553,7 +553,7 @@ void arch_send_call_function_single_ipi(int cpu)
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 }
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 65924d9ec2459..5cf35a774dc70 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -256,7 +256,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 	       (bogosum / (5000/HZ)) % 100);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	mp_ops->send_ipi(cpu, SMP_MSG_RESCHEDULE);
 }
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index ad8094d955eba..87eaa7719fa27 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -120,7 +120,7 @@ void cpu_panic(void)
 
 struct linux_prom_registers smp_penguin_ctable = { 0 };
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	/*
 	 * CPU model dependent way of implementing IPI generation targeting
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index a55295d1b9244..e5964d1d8b37d 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1430,7 +1430,7 @@ static unsigned long send_cpu_poke(int cpu)
 	return hv_err;
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (cpu = smp_processor_id()) {
 		WARN_ON_ONCE(preemptible());
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index a73bced40e241..5ff5815149bd3 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -99,7 +99,7 @@ static inline void play_dead(void)
 	smp_ops.play_dead();
 }
 
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	smp_ops.smp_send_reschedule(cpu);
 }
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 58f0077d93579..b972c6f8c1791 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -26,6 +26,7 @@
 #include <linux/swap.h>
 #include <linux/rwsem.h>
 #include <linux/cc_platform.h>
+#include <linux/smp.h>
 
 #include <asm/apic.h>
 #include <asm/perf_event.h>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 521b433f978c7..3fbc3fea3e754 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -58,6 +58,7 @@
 #include <linux/mem_encrypt.h>
 #include <linux/entry-kvm.h>
 #include <linux/suspend.h>
+#include <linux/smp.h>
 
 #include <trace/events/kvm.h>
 
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index 4dc109dd6214e..d95907b8e4d38 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -389,7 +389,7 @@ void arch_send_call_function_single_ipi(int cpu)
 	send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/include/linux/smp.h b/include/linux/smp.h
index a80ab58ae3f1d..2f9dc1b7a7fb6 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -125,9 +125,9 @@ extern void smp_send_stop(void);
 /*
  * sends a 'reschedule' event to another CPU:
  */
+extern void arch_smp_send_reschedule(int cpu);
 extern void smp_send_reschedule(int cpu);
 
-
 /*
  * Prepare machine for booting other CPUs.
  */
diff --git a/kernel/smp.c b/kernel/smp.c
index c4d561cf50d45..44fa4b9b1f46b 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
 	arch_send_call_function_ipi_mask(mask);
 }
 
+void smp_send_reschedule(int cpu)
+{
+	/* XXX scheduler_ipi is inline :/ */
+	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
+	arch_smp_send_reschedule(cpu);
+}
+EXPORT_SYMBOL_GPL(smp_send_reschedule);
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
-- 
2.31.1

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 7/8] smp: reword smp call IPI comment
  2022-11-02 18:29 ` Valentin Schneider
                     ` (3 preceding siblings ...)
  (?)
@ 2022-11-02 18:33   ` Valentin Schneider
  -1 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Borislav Petkov, Nicholas Piggin, H. Peter Anvin,
	Guo Ren, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

Accessing the call_single_queue hasn't involved a spinlock since 2014:

  6897fc22ea01 ("kernel: use lockless list for smp_call_function_single")

The llist operations (namely cmpxchg() and xchg()) provide similar ordering
guarantees, update the comment to lessen confusion.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index 44fa4b9b1f46b..b96579fe08f09 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -503,9 +503,10 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 #endif
 
 	/*
-	 * The list addition should be visible before sending the IPI
-	 * handler locks the list to pull the entry off it because of
-	 * normal cache coherency rules implied by spinlocks.
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
 	 *
 	 * If IPIs can go out of order to the cache coherency protocol
 	 * in an architecture, sufficient synchronisation should be added
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 7/8] smp: reword smp call IPI comment
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

Accessing the call_single_queue hasn't involved a spinlock since 2014:

  6897fc22ea01 ("kernel: use lockless list for smp_call_function_single")

The llist operations (namely cmpxchg() and xchg()) provide similar ordering
guarantees, update the comment to lessen confusion.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index 44fa4b9b1f46b..b96579fe08f09 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -503,9 +503,10 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 #endif
 
 	/*
-	 * The list addition should be visible before sending the IPI
-	 * handler locks the list to pull the entry off it because of
-	 * normal cache coherency rules implied by spinlocks.
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
 	 *
 	 * If IPIs can go out of order to the cache coherency protocol
 	 * in an architecture, sufficient synchronisation should be added
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 7/8] smp: reword smp call IPI comment
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

Accessing the call_single_queue hasn't involved a spinlock since 2014:

  6897fc22ea01 ("kernel: use lockless list for smp_call_function_single")

The llist operations (namely cmpxchg() and xchg()) provide similar ordering
guarantees, update the comment to lessen confusion.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index 44fa4b9b1f46b..b96579fe08f09 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -503,9 +503,10 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 #endif
 
 	/*
-	 * The list addition should be visible before sending the IPI
-	 * handler locks the list to pull the entry off it because of
-	 * normal cache coherency rules implied by spinlocks.
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
 	 *
 	 * If IPIs can go out of order to the cache coherency protocol
 	 * in an architecture, sufficient synchronisation should be added
-- 
2.31.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 7/8] smp: reword smp call IPI comment
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

Accessing the call_single_queue hasn't involved a spinlock since 2014:

  6897fc22ea01 ("kernel: use lockless list for smp_call_function_single")

The llist operations (namely cmpxchg() and xchg()) provide similar ordering
guarantees, update the comment to lessen confusion.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index 44fa4b9b1f46b..b96579fe08f09 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -503,9 +503,10 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 #endif
 
 	/*
-	 * The list addition should be visible before sending the IPI
-	 * handler locks the list to pull the entry off it because of
-	 * normal cache coherency rules implied by spinlocks.
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
 	 *
 	 * If IPIs can go out of order to the cache coherency protocol
 	 * in an architecture, sufficient synchronisation should be added
-- 
2.31.1


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 7/8] smp: reword smp call IPI comment
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

Accessing the call_single_queue hasn't involved a spinlock since 2014:

  6897fc22ea01 ("kernel: use lockless list for smp_call_function_single")

The llist operations (namely cmpxchg() and xchg()) provide similar ordering
guarantees, update the comment to lessen confusion.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index 44fa4b9b1f46b..b96579fe08f09 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -503,9 +503,10 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 #endif
 
 	/*
-	 * The list addition should be visible before sending the IPI
-	 * handler locks the list to pull the entry off it because of
-	 * normal cache coherency rules implied by spinlocks.
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
 	 *
 	 * If IPIs can go out of order to the cache coherency protocol
 	 * in an architecture, sufficient synchronisation should be added
-- 
2.31.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 7/8] smp: reword smp call IPI comment
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Borislav Petkov, Nicholas Piggin, H. Peter Anvin,
	Guo Ren, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

Accessing the call_single_queue hasn't involved a spinlock since 2014:

  6897fc22ea01 ("kernel: use lockless list for smp_call_function_single")

The llist operations (namely cmpxchg() and xchg()) provide similar ordering
guarantees, update the comment to lessen confusion.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/smp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index 44fa4b9b1f46b..b96579fe08f09 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -503,9 +503,10 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 #endif
 
 	/*
-	 * The list addition should be visible before sending the IPI
-	 * handler locks the list to pull the entry off it because of
-	 * normal cache coherency rules implied by spinlocks.
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
 	 *
 	 * If IPIs can go out of order to the cache coherency protocol
 	 * in an architecture, sufficient synchronisation should be added
-- 
2.31.1

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
  2022-11-02 18:29 ` Valentin Schneider
                     ` (3 preceding siblings ...)
  (?)
@ 2022-11-02 18:33   ` Valentin Schneider
  -1 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Borislav Petkov, Nicholas Piggin, H. Peter Anvin,
	Guo Ren, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
which so far has only been fed with NULL.

While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
struct layout (meaning their callback func can be accessed without caring
about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
attached to its struct. This means we need to check the type of a CSD
before eventually dereferencing its associated callback.

This isn't as trivial as it sounds: the CSD type is stored in
__call_single_node.u_flags, which get cleared right before the callback is
executed via csd_unlock(). This implies checking the CSD type before it is
enqueued on the call_single_queue, as the target CPU's queue can be flushed
before we get to sending an IPI.

Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
would need to have an additional argument to trickle down the invoked
function. This is somewhat silly, as the extra argument will always be
pushed down to the function even when nothing is being traced, which is
unnecessary overhead.

Two options present themselves:
a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
   an extra argument used for tracing, so that codepaths remain unchanged
   when tracing isn't in effect (a sort of manual -fipa-sra).

b) Stash the CSD func in somewhere as a side effect that
   the portion of send_call_function_{single_ipi, ipi_mask}() under the
   tracepoint's static key can fetch.

a) creates redundant code, and b) is quite fragile due to requiring extra
care for "reentrant" functions (async SMP calls).

This implements a).

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c   |  2 ++
 kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
 kernel/sched/smp.h  |  1 +
 kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
 4 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index aec38c294ce68..fcfa75c4a5daf 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 02181f8072b5f..41196ca67e913 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
-{
-	struct rq *rq = cpu_rq(cpu);
-
-	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
-		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
-	}
-}
+/*
+ * We want a variant that traces the function causing the IPI to be sent, but
+ * we don't want the extra argument to cause unnecessary overhead when tracing
+ * isn't happening.
+ */
+#define GEN_CFSI(suffix, IPI_EXP, ...)						\
+void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
+{										\
+	struct rq *rq = cpu_rq(cpu);						\
+										\
+	if (!set_nr_if_polling(rq->idle)) {					\
+		IPI_EXP;							\
+		arch_send_call_function_single_ipi(cpu);			\
+	} else {								\
+		trace_sched_wake_idle_without_ipi(cpu);				\
+	}									\
+}
+
+GEN_CFSI(/* nop */,
+	 /* nop */,
+	 int cpu)
+GEN_CFSI(_trace,
+	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
+	 int cpu, smp_call_func_t func)
 
 /*
  * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
diff --git a/kernel/sched/smp.h b/kernel/sched/smp.h
index 2eb23dd0f2856..8075ad5e84181 100644
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -7,6 +7,7 @@
 extern void sched_ttwu_pending(void *arg);
 
 extern void send_call_function_single_ipi(int cpu);
+extern void send_call_function_single_ipi_trace(int cpu, smp_call_func_t func);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
diff --git a/kernel/smp.c b/kernel/smp.c
index b96579fe08f09..3b8e6456ac7e7 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -161,12 +161,18 @@ void __init call_function_init(void)
 }
 
 static inline void
-send_call_function_ipi_mask(const struct cpumask *mask)
+send_call_function_ipi_mask_trace(const struct cpumask *mask, smp_call_func_t func)
 {
 	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	arch_send_call_function_ipi_mask(mask);
+}
+
 void smp_send_reschedule(int cpu)
 {
 	/* XXX scheduler_ipi is inline :/ */
@@ -438,12 +444,16 @@ static void __smp_call_single_queue_debug(int cpu, struct llist_node *node)
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
-		send_call_function_single_ipi(cpu);
+		send_call_function_single_ipi_trace(cpu, csd->func);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
 		cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
@@ -501,6 +511,26 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 		}
 	}
 #endif
+	/*
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+		func = CSD_TYPE(csd) == CSD_TYPE_TTWU ?
+			sched_ttwu_pending : csd->func;
+
+		/* See below comment on ordering requirements */
+		if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+			send_call_function_single_ipi_trace(cpu, func);
+		return;
+	}
 
 	/*
 	 * The list addition should be visible to the target CPU when it pops
@@ -984,9 +1014,13 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		 * provided mask.
 		 */
 		if (nr_cpus == 1)
-			send_call_function_single_ipi(last_cpu);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_single_ipi_trace(last_cpu, func) :
+				send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_ipi_mask_trace(mask, func) :
+				send_call_function_ipi_mask(mask);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
which so far has only been fed with NULL.

While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
struct layout (meaning their callback func can be accessed without caring
about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
attached to its struct. This means we need to check the type of a CSD
before eventually dereferencing its associated callback.

This isn't as trivial as it sounds: the CSD type is stored in
__call_single_node.u_flags, which get cleared right before the callback is
executed via csd_unlock(). This implies checking the CSD type before it is
enqueued on the call_single_queue, as the target CPU's queue can be flushed
before we get to sending an IPI.

Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
would need to have an additional argument to trickle down the invoked
function. This is somewhat silly, as the extra argument will always be
pushed down to the function even when nothing is being traced, which is
unnecessary overhead.

Two options present themselves:
a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
   an extra argument used for tracing, so that codepaths remain unchanged
   when tracing isn't in effect (a sort of manual -fipa-sra).

b) Stash the CSD func in somewhere as a side effect that
   the portion of send_call_function_{single_ipi, ipi_mask}() under the
   tracepoint's static key can fetch.

a) creates redundant code, and b) is quite fragile due to requiring extra
care for "reentrant" functions (async SMP calls).

This implements a).

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c   |  2 ++
 kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
 kernel/sched/smp.h  |  1 +
 kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
 4 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index aec38c294ce68..fcfa75c4a5daf 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 02181f8072b5f..41196ca67e913 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
-{
-	struct rq *rq = cpu_rq(cpu);
-
-	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
-		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
-	}
-}
+/*
+ * We want a variant that traces the function causing the IPI to be sent, but
+ * we don't want the extra argument to cause unnecessary overhead when tracing
+ * isn't happening.
+ */
+#define GEN_CFSI(suffix, IPI_EXP, ...)						\
+void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
+{										\
+	struct rq *rq = cpu_rq(cpu);						\
+										\
+	if (!set_nr_if_polling(rq->idle)) {					\
+		IPI_EXP;							\
+		arch_send_call_function_single_ipi(cpu);			\
+	} else {								\
+		trace_sched_wake_idle_without_ipi(cpu);				\
+	}									\
+}
+
+GEN_CFSI(/* nop */,
+	 /* nop */,
+	 int cpu)
+GEN_CFSI(_trace,
+	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
+	 int cpu, smp_call_func_t func)
 
 /*
  * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
diff --git a/kernel/sched/smp.h b/kernel/sched/smp.h
index 2eb23dd0f2856..8075ad5e84181 100644
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -7,6 +7,7 @@
 extern void sched_ttwu_pending(void *arg);
 
 extern void send_call_function_single_ipi(int cpu);
+extern void send_call_function_single_ipi_trace(int cpu, smp_call_func_t func);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
diff --git a/kernel/smp.c b/kernel/smp.c
index b96579fe08f09..3b8e6456ac7e7 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -161,12 +161,18 @@ void __init call_function_init(void)
 }
 
 static inline void
-send_call_function_ipi_mask(const struct cpumask *mask)
+send_call_function_ipi_mask_trace(const struct cpumask *mask, smp_call_func_t func)
 {
 	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	arch_send_call_function_ipi_mask(mask);
+}
+
 void smp_send_reschedule(int cpu)
 {
 	/* XXX scheduler_ipi is inline :/ */
@@ -438,12 +444,16 @@ static void __smp_call_single_queue_debug(int cpu, struct llist_node *node)
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
-		send_call_function_single_ipi(cpu);
+		send_call_function_single_ipi_trace(cpu, csd->func);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
 		cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
@@ -501,6 +511,26 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 		}
 	}
 #endif
+	/*
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+		func = CSD_TYPE(csd) == CSD_TYPE_TTWU ?
+			sched_ttwu_pending : csd->func;
+
+		/* See below comment on ordering requirements */
+		if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+			send_call_function_single_ipi_trace(cpu, func);
+		return;
+	}
 
 	/*
 	 * The list addition should be visible to the target CPU when it pops
@@ -984,9 +1014,13 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		 * provided mask.
 		 */
 		if (nr_cpus == 1)
-			send_call_function_single_ipi(last_cpu);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_single_ipi_trace(last_cpu, func) :
+				send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_ipi_mask_trace(mask, func) :
+				send_call_function_ipi_mask(mask);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
which so far has only been fed with NULL.

While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
struct layout (meaning their callback func can be accessed without caring
about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
attached to its struct. This means we need to check the type of a CSD
before eventually dereferencing its associated callback.

This isn't as trivial as it sounds: the CSD type is stored in
__call_single_node.u_flags, which get cleared right before the callback is
executed via csd_unlock(). This implies checking the CSD type before it is
enqueued on the call_single_queue, as the target CPU's queue can be flushed
before we get to sending an IPI.

Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
would need to have an additional argument to trickle down the invoked
function. This is somewhat silly, as the extra argument will always be
pushed down to the function even when nothing is being traced, which is
unnecessary overhead.

Two options present themselves:
a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
   an extra argument used for tracing, so that codepaths remain unchanged
   when tracing isn't in effect (a sort of manual -fipa-sra).

b) Stash the CSD func in somewhere as a side effect that
   the portion of send_call_function_{single_ipi, ipi_mask}() under the
   tracepoint's static key can fetch.

a) creates redundant code, and b) is quite fragile due to requiring extra
care for "reentrant" functions (async SMP calls).

This implements a).

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c   |  2 ++
 kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
 kernel/sched/smp.h  |  1 +
 kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
 4 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index aec38c294ce68..fcfa75c4a5daf 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 02181f8072b5f..41196ca67e913 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
-{
-	struct rq *rq = cpu_rq(cpu);
-
-	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
-		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
-	}
-}
+/*
+ * We want a variant that traces the function causing the IPI to be sent, but
+ * we don't want the extra argument to cause unnecessary overhead when tracing
+ * isn't happening.
+ */
+#define GEN_CFSI(suffix, IPI_EXP, ...)						\
+void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
+{										\
+	struct rq *rq = cpu_rq(cpu);						\
+										\
+	if (!set_nr_if_polling(rq->idle)) {					\
+		IPI_EXP;							\
+		arch_send_call_function_single_ipi(cpu);			\
+	} else {								\
+		trace_sched_wake_idle_without_ipi(cpu);				\
+	}									\
+}
+
+GEN_CFSI(/* nop */,
+	 /* nop */,
+	 int cpu)
+GEN_CFSI(_trace,
+	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
+	 int cpu, smp_call_func_t func)
 
 /*
  * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
diff --git a/kernel/sched/smp.h b/kernel/sched/smp.h
index 2eb23dd0f2856..8075ad5e84181 100644
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -7,6 +7,7 @@
 extern void sched_ttwu_pending(void *arg);
 
 extern void send_call_function_single_ipi(int cpu);
+extern void send_call_function_single_ipi_trace(int cpu, smp_call_func_t func);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
diff --git a/kernel/smp.c b/kernel/smp.c
index b96579fe08f09..3b8e6456ac7e7 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -161,12 +161,18 @@ void __init call_function_init(void)
 }
 
 static inline void
-send_call_function_ipi_mask(const struct cpumask *mask)
+send_call_function_ipi_mask_trace(const struct cpumask *mask, smp_call_func_t func)
 {
 	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	arch_send_call_function_ipi_mask(mask);
+}
+
 void smp_send_reschedule(int cpu)
 {
 	/* XXX scheduler_ipi is inline :/ */
@@ -438,12 +444,16 @@ static void __smp_call_single_queue_debug(int cpu, struct llist_node *node)
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
-		send_call_function_single_ipi(cpu);
+		send_call_function_single_ipi_trace(cpu, csd->func);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
 		cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
@@ -501,6 +511,26 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 		}
 	}
 #endif
+	/*
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+		func = CSD_TYPE(csd) == CSD_TYPE_TTWU ?
+			sched_ttwu_pending : csd->func;
+
+		/* See below comment on ordering requirements */
+		if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+			send_call_function_single_ipi_trace(cpu, func);
+		return;
+	}
 
 	/*
 	 * The list addition should be visible to the target CPU when it pops
@@ -984,9 +1014,13 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		 * provided mask.
 		 */
 		if (nr_cpus == 1)
-			send_call_function_single_ipi(last_cpu);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_single_ipi_trace(last_cpu, func) :
+				send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_ipi_mask_trace(mask, func) :
+				send_call_function_ipi_mask(mask);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
which so far has only been fed with NULL.

While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
struct layout (meaning their callback func can be accessed without caring
about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
attached to its struct. This means we need to check the type of a CSD
before eventually dereferencing its associated callback.

This isn't as trivial as it sounds: the CSD type is stored in
__call_single_node.u_flags, which get cleared right before the callback is
executed via csd_unlock(). This implies checking the CSD type before it is
enqueued on the call_single_queue, as the target CPU's queue can be flushed
before we get to sending an IPI.

Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
would need to have an additional argument to trickle down the invoked
function. This is somewhat silly, as the extra argument will always be
pushed down to the function even when nothing is being traced, which is
unnecessary overhead.

Two options present themselves:
a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
   an extra argument used for tracing, so that codepaths remain unchanged
   when tracing isn't in effect (a sort of manual -fipa-sra).

b) Stash the CSD func in somewhere as a side effect that
   the portion of send_call_function_{single_ipi, ipi_mask}() under the
   tracepoint's static key can fetch.

a) creates redundant code, and b) is quite fragile due to requiring extra
care for "reentrant" functions (async SMP calls).

This implements a).

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c   |  2 ++
 kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
 kernel/sched/smp.h  |  1 +
 kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
 4 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index aec38c294ce68..fcfa75c4a5daf 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 02181f8072b5f..41196ca67e913 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
-{
-	struct rq *rq = cpu_rq(cpu);
-
-	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
-		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
-	}
-}
+/*
+ * We want a variant that traces the function causing the IPI to be sent, but
+ * we don't want the extra argument to cause unnecessary overhead when tracing
+ * isn't happening.
+ */
+#define GEN_CFSI(suffix, IPI_EXP, ...)						\
+void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
+{										\
+	struct rq *rq = cpu_rq(cpu);						\
+										\
+	if (!set_nr_if_polling(rq->idle)) {					\
+		IPI_EXP;							\
+		arch_send_call_function_single_ipi(cpu);			\
+	} else {								\
+		trace_sched_wake_idle_without_ipi(cpu);				\
+	}									\
+}
+
+GEN_CFSI(/* nop */,
+	 /* nop */,
+	 int cpu)
+GEN_CFSI(_trace,
+	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
+	 int cpu, smp_call_func_t func)
 
 /*
  * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
diff --git a/kernel/sched/smp.h b/kernel/sched/smp.h
index 2eb23dd0f2856..8075ad5e84181 100644
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -7,6 +7,7 @@
 extern void sched_ttwu_pending(void *arg);
 
 extern void send_call_function_single_ipi(int cpu);
+extern void send_call_function_single_ipi_trace(int cpu, smp_call_func_t func);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
diff --git a/kernel/smp.c b/kernel/smp.c
index b96579fe08f09..3b8e6456ac7e7 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -161,12 +161,18 @@ void __init call_function_init(void)
 }
 
 static inline void
-send_call_function_ipi_mask(const struct cpumask *mask)
+send_call_function_ipi_mask_trace(const struct cpumask *mask, smp_call_func_t func)
 {
 	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	arch_send_call_function_ipi_mask(mask);
+}
+
 void smp_send_reschedule(int cpu)
 {
 	/* XXX scheduler_ipi is inline :/ */
@@ -438,12 +444,16 @@ static void __smp_call_single_queue_debug(int cpu, struct llist_node *node)
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
-		send_call_function_single_ipi(cpu);
+		send_call_function_single_ipi_trace(cpu, csd->func);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
 		cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
@@ -501,6 +511,26 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 		}
 	}
 #endif
+	/*
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+		func = CSD_TYPE(csd) == CSD_TYPE_TTWU ?
+			sched_ttwu_pending : csd->func;
+
+		/* See below comment on ordering requirements */
+		if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+			send_call_function_single_ipi_trace(cpu, func);
+		return;
+	}
 
 	/*
 	 * The list addition should be visible to the target CPU when it pops
@@ -984,9 +1014,13 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		 * provided mask.
 		 */
 		if (nr_cpus == 1)
-			send_call_function_single_ipi(last_cpu);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_single_ipi_trace(last_cpu, func) :
+				send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_ipi_mask_trace(mask, func) :
+				send_call_function_ipi_mask(mask);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Paul E. McKenney, Steven Rostedt, Peter Zijlstra,
	Thomas Gleixner, Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	Guo Ren, David S. Miller

The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
which so far has only been fed with NULL.

While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
struct layout (meaning their callback func can be accessed without caring
about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
attached to its struct. This means we need to check the type of a CSD
before eventually dereferencing its associated callback.

This isn't as trivial as it sounds: the CSD type is stored in
__call_single_node.u_flags, which get cleared right before the callback is
executed via csd_unlock(). This implies checking the CSD type before it is
enqueued on the call_single_queue, as the target CPU's queue can be flushed
before we get to sending an IPI.

Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
would need to have an additional argument to trickle down the invoked
function. This is somewhat silly, as the extra argument will always be
pushed down to the function even when nothing is being traced, which is
unnecessary overhead.

Two options present themselves:
a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
   an extra argument used for tracing, so that codepaths remain unchanged
   when tracing isn't in effect (a sort of manual -fipa-sra).

b) Stash the CSD func in somewhere as a side effect that
   the portion of send_call_function_{single_ipi, ipi_mask}() under the
   tracepoint's static key can fetch.

a) creates redundant code, and b) is quite fragile due to requiring extra
care for "reentrant" functions (async SMP calls).

This implements a).

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c   |  2 ++
 kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
 kernel/sched/smp.h  |  1 +
 kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
 4 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index aec38c294ce68..fcfa75c4a5daf 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 02181f8072b5f..41196ca67e913 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
-{
-	struct rq *rq = cpu_rq(cpu);
-
-	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
-		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
-	}
-}
+/*
+ * We want a variant that traces the function causing the IPI to be sent, but
+ * we don't want the extra argument to cause unnecessary overhead when tracing
+ * isn't happening.
+ */
+#define GEN_CFSI(suffix, IPI_EXP, ...)						\
+void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
+{										\
+	struct rq *rq = cpu_rq(cpu);						\
+										\
+	if (!set_nr_if_polling(rq->idle)) {					\
+		IPI_EXP;							\
+		arch_send_call_function_single_ipi(cpu);			\
+	} else {								\
+		trace_sched_wake_idle_without_ipi(cpu);				\
+	}									\
+}
+
+GEN_CFSI(/* nop */,
+	 /* nop */,
+	 int cpu)
+GEN_CFSI(_trace,
+	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
+	 int cpu, smp_call_func_t func)
 
 /*
  * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
diff --git a/kernel/sched/smp.h b/kernel/sched/smp.h
index 2eb23dd0f2856..8075ad5e84181 100644
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -7,6 +7,7 @@
 extern void sched_ttwu_pending(void *arg);
 
 extern void send_call_function_single_ipi(int cpu);
+extern void send_call_function_single_ipi_trace(int cpu, smp_call_func_t func);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
diff --git a/kernel/smp.c b/kernel/smp.c
index b96579fe08f09..3b8e6456ac7e7 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -161,12 +161,18 @@ void __init call_function_init(void)
 }
 
 static inline void
-send_call_function_ipi_mask(const struct cpumask *mask)
+send_call_function_ipi_mask_trace(const struct cpumask *mask, smp_call_func_t func)
 {
 	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	arch_send_call_function_ipi_mask(mask);
+}
+
 void smp_send_reschedule(int cpu)
 {
 	/* XXX scheduler_ipi is inline :/ */
@@ -438,12 +444,16 @@ static void __smp_call_single_queue_debug(int cpu, struct llist_node *node)
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
-		send_call_function_single_ipi(cpu);
+		send_call_function_single_ipi_trace(cpu, csd->func);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
 		cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
@@ -501,6 +511,26 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 		}
 	}
 #endif
+	/*
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+		func = CSD_TYPE(csd) == CSD_TYPE_TTWU ?
+			sched_ttwu_pending : csd->func;
+
+		/* See below comment on ordering requirements */
+		if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+			send_call_function_single_ipi_trace(cpu, func);
+		return;
+	}
 
 	/*
 	 * The list addition should be visible to the target CPU when it pops
@@ -984,9 +1014,13 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		 * provided mask.
 		 */
 		if (nr_cpus == 1)
-			send_call_function_single_ipi(last_cpu);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_single_ipi_trace(last_cpu, func) :
+				send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_ipi_mask_trace(mask, func) :
+				send_call_function_ipi_mask(mask);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-02 18:33   ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-02 18:33 UTC (permalink / raw)
  To: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86
  Cc: Juri Lelli, Mark Rutland, Dave Hansen, Paul E. McKenney,
	Peter Zijlstra, Marc Zyngier, Sebastian Andrzej Siewior,
	Marcelo Tosatti, Russell King, Steven Rostedt, David S. Miller,
	Ingo Molnar, Borislav Petkov, Nicholas Piggin, H. Peter Anvin,
	Guo Ren, Thomas Gleixner, Daniel Bristot de Oliveira,
	Frederic Weisbecker

The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
which so far has only been fed with NULL.

While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
struct layout (meaning their callback func can be accessed without caring
about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
attached to its struct. This means we need to check the type of a CSD
before eventually dereferencing its associated callback.

This isn't as trivial as it sounds: the CSD type is stored in
__call_single_node.u_flags, which get cleared right before the callback is
executed via csd_unlock(). This implies checking the CSD type before it is
enqueued on the call_single_queue, as the target CPU's queue can be flushed
before we get to sending an IPI.

Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
would need to have an additional argument to trickle down the invoked
function. This is somewhat silly, as the extra argument will always be
pushed down to the function even when nothing is being traced, which is
unnecessary overhead.

Two options present themselves:
a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
   an extra argument used for tracing, so that codepaths remain unchanged
   when tracing isn't in effect (a sort of manual -fipa-sra).

b) Stash the CSD func in somewhere as a side effect that
   the portion of send_call_function_{single_ipi, ipi_mask}() under the
   tracepoint's static key can fetch.

a) creates redundant code, and b) is quite fragile due to requiring extra
care for "reentrant" functions (async SMP calls).

This implements a).

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/irq_work.c   |  2 ++
 kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
 kernel/sched/smp.h  |  1 +
 kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
 4 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index aec38c294ce68..fcfa75c4a5daf 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 02181f8072b5f..41196ca67e913 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
-{
-	struct rq *rq = cpu_rq(cpu);
-
-	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
-		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
-	}
-}
+/*
+ * We want a variant that traces the function causing the IPI to be sent, but
+ * we don't want the extra argument to cause unnecessary overhead when tracing
+ * isn't happening.
+ */
+#define GEN_CFSI(suffix, IPI_EXP, ...)						\
+void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
+{										\
+	struct rq *rq = cpu_rq(cpu);						\
+										\
+	if (!set_nr_if_polling(rq->idle)) {					\
+		IPI_EXP;							\
+		arch_send_call_function_single_ipi(cpu);			\
+	} else {								\
+		trace_sched_wake_idle_without_ipi(cpu);				\
+	}									\
+}
+
+GEN_CFSI(/* nop */,
+	 /* nop */,
+	 int cpu)
+GEN_CFSI(_trace,
+	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
+	 int cpu, smp_call_func_t func)
 
 /*
  * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
diff --git a/kernel/sched/smp.h b/kernel/sched/smp.h
index 2eb23dd0f2856..8075ad5e84181 100644
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -7,6 +7,7 @@
 extern void sched_ttwu_pending(void *arg);
 
 extern void send_call_function_single_ipi(int cpu);
+extern void send_call_function_single_ipi_trace(int cpu, smp_call_func_t func);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
diff --git a/kernel/smp.c b/kernel/smp.c
index b96579fe08f09..3b8e6456ac7e7 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -161,12 +161,18 @@ void __init call_function_init(void)
 }
 
 static inline void
-send_call_function_ipi_mask(const struct cpumask *mask)
+send_call_function_ipi_mask_trace(const struct cpumask *mask, smp_call_func_t func)
 {
 	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
+static inline void
+send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	arch_send_call_function_ipi_mask(mask);
+}
+
 void smp_send_reschedule(int cpu)
 {
 	/* XXX scheduler_ipi is inline :/ */
@@ -438,12 +444,16 @@ static void __smp_call_single_queue_debug(int cpu, struct llist_node *node)
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
-		send_call_function_single_ipi(cpu);
+		send_call_function_single_ipi_trace(cpu, csd->func);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
 		cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
@@ -501,6 +511,26 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
 		}
 	}
 #endif
+	/*
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+		func = CSD_TYPE(csd) = CSD_TYPE_TTWU ?
+			sched_ttwu_pending : csd->func;
+
+		/* See below comment on ordering requirements */
+		if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+			send_call_function_single_ipi_trace(cpu, func);
+		return;
+	}
 
 	/*
 	 * The list addition should be visible to the target CPU when it pops
@@ -984,9 +1014,13 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 		 * provided mask.
 		 */
 		if (nr_cpus = 1)
-			send_call_function_single_ipi(last_cpu);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_single_ipi_trace(last_cpu, func) :
+				send_call_function_single_ipi(last_cpu);
 		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+			trace_ipi_send_cpumask_enabled() ?
+				send_call_function_ipi_mask_trace(mask, func) :
+				send_call_function_ipi_mask(mask);
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}
-- 
2.31.1

^ permalink raw reply related	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 0/8] Generic IPI sending tracepoint
  2022-11-02 18:29 ` Valentin Schneider
                     ` (5 preceding siblings ...)
  (?)
@ 2022-11-14 17:27   ` Steven Rostedt
  -1 siblings, 0 replies; 131+ messages in thread
From: Steven Rostedt @ 2022-11-14 17:27 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Peter Zijlstra, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed,  2 Nov 2022 18:29:41 +0000
Valentin Schneider <vschneid@redhat.com> wrote:

> This is incomplete, just looking at arm64 there's more IPI types that aren't
> covered: 
> 
>   IPI_CPU_STOP,
>   IPI_CPU_CRASH_STOP,
>   IPI_TIMER,
>   IPI_WAKEUP,
> 
> ... But it feels like a good starting point.

For the tracing portions:

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-14 17:27   ` Steven Rostedt
  0 siblings, 0 replies; 131+ messages in thread
From: Steven Rostedt @ 2022-11-14 17:27 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Peter Zijlstra, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed,  2 Nov 2022 18:29:41 +0000
Valentin Schneider <vschneid@redhat.com> wrote:

> This is incomplete, just looking at arm64 there's more IPI types that aren't
> covered: 
> 
>   IPI_CPU_STOP,
>   IPI_CPU_CRASH_STOP,
>   IPI_TIMER,
>   IPI_WAKEUP,
> 
> ... But it feels like a good starting point.

For the tracing portions:

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-14 17:27   ` Steven Rostedt
  0 siblings, 0 replies; 131+ messages in thread
From: Steven Rostedt @ 2022-11-14 17:27 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh, Peter Zijlstra,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Nicholas Piggin, openrisc, Borislav Petkov,
	loongarch, Thomas Gleixner, linux-arm-kernel, linux-parisc,
	Daniel Bristot de Oliveira, Marcelo Tosatti, linux-kernel,
	linux-alpha, linuxppc-dev, David S. Miller

On Wed,  2 Nov 2022 18:29:41 +0000
Valentin Schneider <vschneid@redhat.com> wrote:

> This is incomplete, just looking at arm64 there's more IPI types that aren't
> covered: 
> 
>   IPI_CPU_STOP,
>   IPI_CPU_CRASH_STOP,
>   IPI_TIMER,
>   IPI_WAKEUP,
> 
> ... But it feels like a good starting point.

For the tracing portions:

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-14 17:27   ` Steven Rostedt
  0 siblings, 0 replies; 131+ messages in thread
From: Steven Rostedt @ 2022-11-14 17:27 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Peter Zijlstra, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed,  2 Nov 2022 18:29:41 +0000
Valentin Schneider <vschneid@redhat.com> wrote:

> This is incomplete, just looking at arm64 there's more IPI types that aren't
> covered: 
> 
>   IPI_CPU_STOP,
>   IPI_CPU_CRASH_STOP,
>   IPI_TIMER,
>   IPI_WAKEUP,
> 
> ... But it feels like a good starting point.

For the tracing portions:

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-14 17:27   ` Steven Rostedt
  0 siblings, 0 replies; 131+ messages in thread
From: Steven Rostedt @ 2022-11-14 17:27 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh, Peter Zijlstra,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Nicholas Piggin, openrisc, Borislav Petkov,
	loongarch, Thomas Gleixner, linux-arm-kernel, linux-parisc,
	Daniel Bristot de Oliveira, Marcelo Tosatti, linux-kernel,
	linux-alpha, linuxppc-dev, David S. Miller

On Wed,  2 Nov 2022 18:29:41 +0000
Valentin Schneider <vschneid@redhat.com> wrote:

> This is incomplete, just looking at arm64 there's more IPI types that aren't
> covered: 
> 
>   IPI_CPU_STOP,
>   IPI_CPU_CRASH_STOP,
>   IPI_TIMER,
>   IPI_WAKEUP,
> 
> ... But it feels like a good starting point.

For the tracing portions:

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-14 17:27   ` Steven Rostedt
  0 siblings, 0 replies; 131+ messages in thread
From: Steven Rostedt @ 2022-11-14 17:27 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Peter Zijlstra, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed,  2 Nov 2022 18:29:41 +0000
Valentin Schneider <vschneid@redhat.com> wrote:

> This is incomplete, just looking at arm64 there's more IPI types that aren't
> covered: 
> 
>   IPI_CPU_STOP,
>   IPI_CPU_CRASH_STOP,
>   IPI_TIMER,
>   IPI_WAKEUP,
> 
> ... But it feels like a good starting point.

For the tracing portions:

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-14 17:27   ` Steven Rostedt
  0 siblings, 0 replies; 131+ messages in thread
From: Steven Rostedt @ 2022-11-14 17:27 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Peter Zijlstra, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed,  2 Nov 2022 18:29:41 +0000
Valentin Schneider <vschneid@redhat.com> wrote:

> This is incomplete, just looking at arm64 there's more IPI types that aren't
> covered: 
> 
>   IPI_CPU_STOP,
>   IPI_CPU_CRASH_STOP,
>   IPI_TIMER,
>   IPI_WAKEUP,
> 
> ... But it feels like a good starting point.

For the tracing portions:

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 0/8] Generic IPI sending tracepoint
@ 2022-11-14 17:27   ` Steven Rostedt
  0 siblings, 0 replies; 131+ messages in thread
From: Steven Rostedt @ 2022-11-14 17:27 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Peter Zijlstra, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira

On Wed,  2 Nov 2022 18:29:41 +0000
Valentin Schneider <vschneid@redhat.com> wrote:

> This is incomplete, just looking at arm64 there's more IPI types that aren't
> covered: 
> 
>   IPI_CPU_STOP,
>   IPI_CPU_CRASH_STOP,
>   IPI_TIMER,
>   IPI_WAKEUP,
> 
> ... But it feels like a good starting point.

For the tracing portions:

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
  2022-11-02 18:33   ` Valentin Schneider
                       ` (5 preceding siblings ...)
  (?)
@ 2022-11-17  9:08     ` Peter Zijlstra
  -1 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:08 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
> This simply wraps around the arch function and prepends it with a
> tracepoint, similar to send_call_function_single_ipi().
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/smp.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/smp.c b/kernel/smp.c
> index e2ca1e2f31274..c4d561cf50d45 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>  	smpcfd_prepare_cpu(smp_processor_id());
>  }
>  
> +static inline void

Given the use of _RET_IP_, I would strongly recommend you use
__always_inline.

> +send_call_function_ipi_mask(const struct cpumask *mask)
> +{
> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);

What's func?

> +	arch_send_call_function_ipi_mask(mask);
> +}

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17  9:08     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:08 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
> This simply wraps around the arch function and prepends it with a
> tracepoint, similar to send_call_function_single_ipi().
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/smp.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/smp.c b/kernel/smp.c
> index e2ca1e2f31274..c4d561cf50d45 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>  	smpcfd_prepare_cpu(smp_processor_id());
>  }
>  
> +static inline void

Given the use of _RET_IP_, I would strongly recommend you use
__always_inline.

> +send_call_function_ipi_mask(const struct cpumask *mask)
> +{
> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);

What's func?

> +	arch_send_call_function_ipi_mask(mask);
> +}

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17  9:08     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:08 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
> This simply wraps around the arch function and prepends it with a
> tracepoint, similar to send_call_function_single_ipi().
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/smp.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/smp.c b/kernel/smp.c
> index e2ca1e2f31274..c4d561cf50d45 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>  	smpcfd_prepare_cpu(smp_processor_id());
>  }
>  
> +static inline void

Given the use of _RET_IP_, I would strongly recommend you use
__always_inline.

> +send_call_function_ipi_mask(const struct cpumask *mask)
> +{
> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);

What's func?

> +	arch_send_call_function_ipi_mask(mask);
> +}

_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17  9:08     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:08 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
> This simply wraps around the arch function and prepends it with a
> tracepoint, similar to send_call_function_single_ipi().
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/smp.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/smp.c b/kernel/smp.c
> index e2ca1e2f31274..c4d561cf50d45 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>  	smpcfd_prepare_cpu(smp_processor_id());
>  }
>  
> +static inline void

Given the use of _RET_IP_, I would strongly recommend you use
__always_inline.

> +send_call_function_ipi_mask(const struct cpumask *mask)
> +{
> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);

What's func?

> +	arch_send_call_function_ipi_mask(mask);
> +}

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17  9:08     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:08 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
> This simply wraps around the arch function and prepends it with a
> tracepoint, similar to send_call_function_single_ipi().
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/smp.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/smp.c b/kernel/smp.c
> index e2ca1e2f31274..c4d561cf50d45 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>  	smpcfd_prepare_cpu(smp_processor_id());
>  }
>  
> +static inline void

Given the use of _RET_IP_, I would strongly recommend you use
__always_inline.

> +send_call_function_ipi_mask(const struct cpumask *mask)
> +{
> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);

What's func?

> +	arch_send_call_function_ipi_mask(mask);
> +}

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17  9:08     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:08 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
> This simply wraps around the arch function and prepends it with a
> tracepoint, similar to send_call_function_single_ipi().
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/smp.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/smp.c b/kernel/smp.c
> index e2ca1e2f31274..c4d561cf50d45 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>  	smpcfd_prepare_cpu(smp_processor_id());
>  }
>  
> +static inline void

Given the use of _RET_IP_, I would strongly recommend you use
__always_inline.

> +send_call_function_ipi_mask(const struct cpumask *mask)
> +{
> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);

What's func?

> +	arch_send_call_function_ipi_mask(mask);
> +}

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17  9:08     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:08 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
> This simply wraps around the arch function and prepends it with a
> tracepoint, similar to send_call_function_single_ipi().
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/smp.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/smp.c b/kernel/smp.c
> index e2ca1e2f31274..c4d561cf50d45 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>  	smpcfd_prepare_cpu(smp_processor_id());
>  }
>  
> +static inline void

Given the use of _RET_IP_, I would strongly recommend you use
__always_inline.

> +send_call_function_ipi_mask(const struct cpumask *mask)
> +{
> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);

What's func?

> +	arch_send_call_function_ipi_mask(mask);
> +}

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17  9:08     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:08 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar

On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
> This simply wraps around the arch function and prepends it with a
> tracepoint, similar to send_call_function_single_ipi().
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/smp.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/smp.c b/kernel/smp.c
> index e2ca1e2f31274..c4d561cf50d45 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>  	smpcfd_prepare_cpu(smp_processor_id());
>  }
>  
> +static inline void

Given the use of _RET_IP_, I would strongly recommend you use
__always_inline.

> +send_call_function_ipi_mask(const struct cpumask *mask)
> +{
> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);

What's func?

> +	arch_send_call_function_ipi_mask(mask);
> +}

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
  2022-11-02 18:33   ` Valentin Schneider
                       ` (5 preceding siblings ...)
  (?)
@ 2022-11-17  9:10     ` Peter Zijlstra
  -1 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:10 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:33PM +0000, Valentin Schneider wrote:
> IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
> trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
> self-IPIs.
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index 7afa40fe5cc43..aec38c294ce68 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -22,6 +22,8 @@
>  #include <asm/processor.h>
>  #include <linux/kasan.h>
>  
> +#include <trace/events/ipi.h>
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> @@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
>  	 */
>  }
>  
> +static inline void irq_work_raise(struct irq_work *work)

__always_inline, unless you want to occasionally only see it point to
__irq_work_queue_local().

> +{
> +	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt()) {
> +		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
> +				       _RET_IP_,
> +				       work->func);
	}
> +
> +	arch_irq_work_raise();
> +}
> +
>  /* Enqueue on current CPU, work must already be claimed and preempt disabled */
>  static void __irq_work_queue_local(struct irq_work *work)
>  {
> @@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
>  
>  	/* If the work is "lazy", handle it from next tick if any */
>  	if (!lazy_work || tick_nohz_tick_stopped())
> -		arch_irq_work_raise();
> +		irq_work_raise(work);
>  }
>  
>  /* Enqueue the irq work @work on the current CPU */
> -- 
> 2.31.1
> 

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-17  9:10     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:10 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:33PM +0000, Valentin Schneider wrote:
> IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
> trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
> self-IPIs.
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index 7afa40fe5cc43..aec38c294ce68 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -22,6 +22,8 @@
>  #include <asm/processor.h>
>  #include <linux/kasan.h>
>  
> +#include <trace/events/ipi.h>
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> @@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
>  	 */
>  }
>  
> +static inline void irq_work_raise(struct irq_work *work)

__always_inline, unless you want to occasionally only see it point to
__irq_work_queue_local().

> +{
> +	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt()) {
> +		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
> +				       _RET_IP_,
> +				       work->func);
	}
> +
> +	arch_irq_work_raise();
> +}
> +
>  /* Enqueue on current CPU, work must already be claimed and preempt disabled */
>  static void __irq_work_queue_local(struct irq_work *work)
>  {
> @@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
>  
>  	/* If the work is "lazy", handle it from next tick if any */
>  	if (!lazy_work || tick_nohz_tick_stopped())
> -		arch_irq_work_raise();
> +		irq_work_raise(work);
>  }
>  
>  /* Enqueue the irq work @work on the current CPU */
> -- 
> 2.31.1
> 

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-17  9:10     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:10 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:33PM +0000, Valentin Schneider wrote:
> IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
> trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
> self-IPIs.
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index 7afa40fe5cc43..aec38c294ce68 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -22,6 +22,8 @@
>  #include <asm/processor.h>
>  #include <linux/kasan.h>
>  
> +#include <trace/events/ipi.h>
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> @@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
>  	 */
>  }
>  
> +static inline void irq_work_raise(struct irq_work *work)

__always_inline, unless you want to occasionally only see it point to
__irq_work_queue_local().

> +{
> +	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt()) {
> +		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
> +				       _RET_IP_,
> +				       work->func);
	}
> +
> +	arch_irq_work_raise();
> +}
> +
>  /* Enqueue on current CPU, work must already be claimed and preempt disabled */
>  static void __irq_work_queue_local(struct irq_work *work)
>  {
> @@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
>  
>  	/* If the work is "lazy", handle it from next tick if any */
>  	if (!lazy_work || tick_nohz_tick_stopped())
> -		arch_irq_work_raise();
> +		irq_work_raise(work);
>  }
>  
>  /* Enqueue the irq work @work on the current CPU */
> -- 
> 2.31.1
> 

_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-17  9:10     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:10 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On Wed, Nov 02, 2022 at 06:33:33PM +0000, Valentin Schneider wrote:
> IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
> trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
> self-IPIs.
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index 7afa40fe5cc43..aec38c294ce68 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -22,6 +22,8 @@
>  #include <asm/processor.h>
>  #include <linux/kasan.h>
>  
> +#include <trace/events/ipi.h>
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> @@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
>  	 */
>  }
>  
> +static inline void irq_work_raise(struct irq_work *work)

__always_inline, unless you want to occasionally only see it point to
__irq_work_queue_local().

> +{
> +	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt()) {
> +		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
> +				       _RET_IP_,
> +				       work->func);
	}
> +
> +	arch_irq_work_raise();
> +}
> +
>  /* Enqueue on current CPU, work must already be claimed and preempt disabled */
>  static void __irq_work_queue_local(struct irq_work *work)
>  {
> @@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
>  
>  	/* If the work is "lazy", handle it from next tick if any */
>  	if (!lazy_work || tick_nohz_tick_stopped())
> -		arch_irq_work_raise();
> +		irq_work_raise(work);
>  }
>  
>  /* Enqueue the irq work @work on the current CPU */
> -- 
> 2.31.1
> 

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-17  9:10     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:10 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On Wed, Nov 02, 2022 at 06:33:33PM +0000, Valentin Schneider wrote:
> IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
> trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
> self-IPIs.
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index 7afa40fe5cc43..aec38c294ce68 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -22,6 +22,8 @@
>  #include <asm/processor.h>
>  #include <linux/kasan.h>
>  
> +#include <trace/events/ipi.h>
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> @@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
>  	 */
>  }
>  
> +static inline void irq_work_raise(struct irq_work *work)

__always_inline, unless you want to occasionally only see it point to
__irq_work_queue_local().

> +{
> +	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt()) {
> +		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
> +				       _RET_IP_,
> +				       work->func);
	}
> +
> +	arch_irq_work_raise();
> +}
> +
>  /* Enqueue on current CPU, work must already be claimed and preempt disabled */
>  static void __irq_work_queue_local(struct irq_work *work)
>  {
> @@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
>  
>  	/* If the work is "lazy", handle it from next tick if any */
>  	if (!lazy_work || tick_nohz_tick_stopped())
> -		arch_irq_work_raise();
> +		irq_work_raise(work);
>  }
>  
>  /* Enqueue the irq work @work on the current CPU */
> -- 
> 2.31.1
> 

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-17  9:10     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:10 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:33PM +0000, Valentin Schneider wrote:
> IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
> trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
> self-IPIs.
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index 7afa40fe5cc43..aec38c294ce68 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -22,6 +22,8 @@
>  #include <asm/processor.h>
>  #include <linux/kasan.h>
>  
> +#include <trace/events/ipi.h>
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> @@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
>  	 */
>  }
>  
> +static inline void irq_work_raise(struct irq_work *work)

__always_inline, unless you want to occasionally only see it point to
__irq_work_queue_local().

> +{
> +	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt()) {
> +		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
> +				       _RET_IP_,
> +				       work->func);
	}
> +
> +	arch_irq_work_raise();
> +}
> +
>  /* Enqueue on current CPU, work must already be claimed and preempt disabled */
>  static void __irq_work_queue_local(struct irq_work *work)
>  {
> @@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
>  
>  	/* If the work is "lazy", handle it from next tick if any */
>  	if (!lazy_work || tick_nohz_tick_stopped())
> -		arch_irq_work_raise();
> +		irq_work_raise(work);
>  }
>  
>  /* Enqueue the irq work @work on the current CPU */
> -- 
> 2.31.1
> 

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-17  9:10     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:10 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:33PM +0000, Valentin Schneider wrote:
> IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
> trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
> self-IPIs.
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index 7afa40fe5cc43..aec38c294ce68 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -22,6 +22,8 @@
>  #include <asm/processor.h>
>  #include <linux/kasan.h>
>  
> +#include <trace/events/ipi.h>
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> @@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
>  	 */
>  }
>  
> +static inline void irq_work_raise(struct irq_work *work)

__always_inline, unless you want to occasionally only see it point to
__irq_work_queue_local().

> +{
> +	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt()) {
> +		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
> +				       _RET_IP_,
> +				       work->func);
	}
> +
> +	arch_irq_work_raise();
> +}
> +
>  /* Enqueue on current CPU, work must already be claimed and preempt disabled */
>  static void __irq_work_queue_local(struct irq_work *work)
>  {
> @@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
>  
>  	/* If the work is "lazy", handle it from next tick if any */
>  	if (!lazy_work || tick_nohz_tick_stopped())
> -		arch_irq_work_raise();
> +		irq_work_raise(work);
>  }
>  
>  /* Enqueue the irq work @work on the current CPU */
> -- 
> 2.31.1
> 

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise()
@ 2022-11-17  9:10     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:10 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar

On Wed, Nov 02, 2022 at 06:33:33PM +0000, Valentin Schneider wrote:
> IPIs sent to remove CPUs via irq_work_queue_on() are now covered by
> trace_ipi_send_cpumask(), add another instance of the tracepoint to cover
> self-IPIs.
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index 7afa40fe5cc43..aec38c294ce68 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -22,6 +22,8 @@
>  #include <asm/processor.h>
>  #include <linux/kasan.h>
>  
> +#include <trace/events/ipi.h>
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> @@ -74,6 +76,16 @@ void __weak arch_irq_work_raise(void)
>  	 */
>  }
>  
> +static inline void irq_work_raise(struct irq_work *work)

__always_inline, unless you want to occasionally only see it point to
__irq_work_queue_local().

> +{
> +	if (trace_ipi_send_cpumask_enabled() && arch_irq_work_has_interrupt()) {
> +		trace_ipi_send_cpumask(cpumask_of(smp_processor_id()),
> +				       _RET_IP_,
> +				       work->func);
	}
> +
> +	arch_irq_work_raise();
> +}
> +
>  /* Enqueue on current CPU, work must already be claimed and preempt disabled */
>  static void __irq_work_queue_local(struct irq_work *work)
>  {
> @@ -99,7 +111,7 @@ static void __irq_work_queue_local(struct irq_work *work)
>  
>  	/* If the work is "lazy", handle it from next tick if any */
>  	if (!lazy_work || tick_nohz_tick_stopped())
> -		arch_irq_work_raise();
> +		irq_work_raise(work);
>  }
>  
>  /* Enqueue the irq work @work on the current CPU */
> -- 
> 2.31.1
> 

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
  2022-11-02 18:33   ` Valentin Schneider
                       ` (5 preceding siblings ...)
  (?)
@ 2022-11-17  9:12     ` Peter Zijlstra
  -1 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Guo Ren,
	Paul E. McKenney, Steven Rostedt, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:

> diff --git a/kernel/smp.c b/kernel/smp.c
> index c4d561cf50d45..44fa4b9b1f46b 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>  	arch_send_call_function_ipi_mask(mask);
>  }
>  
> +void smp_send_reschedule(int cpu)
> +{
> +	/* XXX scheduler_ipi is inline :/ */
> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> +	arch_smp_send_reschedule(cpu);
> +}
> +EXPORT_SYMBOL_GPL(smp_send_reschedule);

Yeah, no.. I see some crazy archs do this, but no we're not exporting
this in generic.

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17  9:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Guo Ren,
	Paul E. McKenney, Steven Rostedt, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:

> diff --git a/kernel/smp.c b/kernel/smp.c
> index c4d561cf50d45..44fa4b9b1f46b 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>  	arch_send_call_function_ipi_mask(mask);
>  }
>  
> +void smp_send_reschedule(int cpu)
> +{
> +	/* XXX scheduler_ipi is inline :/ */
> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> +	arch_smp_send_reschedule(cpu);
> +}
> +EXPORT_SYMBOL_GPL(smp_send_reschedule);

Yeah, no.. I see some crazy archs do this, but no we're not exporting
this in generic.

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17  9:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Guo Ren,
	Paul E. McKenney, Steven Rostedt, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:

> diff --git a/kernel/smp.c b/kernel/smp.c
> index c4d561cf50d45..44fa4b9b1f46b 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>  	arch_send_call_function_ipi_mask(mask);
>  }
>  
> +void smp_send_reschedule(int cpu)
> +{
> +	/* XXX scheduler_ipi is inline :/ */
> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> +	arch_smp_send_reschedule(cpu);
> +}
> +EXPORT_SYMBOL_GPL(smp_send_reschedule);

Yeah, no.. I see some crazy archs do this, but no we're not exporting
this in generic.

_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17  9:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Guo Ren,
	Paul E. McKenney, Steven Rostedt, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:

> diff --git a/kernel/smp.c b/kernel/smp.c
> index c4d561cf50d45..44fa4b9b1f46b 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>  	arch_send_call_function_ipi_mask(mask);
>  }
>  
> +void smp_send_reschedule(int cpu)
> +{
> +	/* XXX scheduler_ipi is inline :/ */
> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> +	arch_smp_send_reschedule(cpu);
> +}
> +EXPORT_SYMBOL_GPL(smp_send_reschedule);

Yeah, no.. I see some crazy archs do this, but no we're not exporting
this in generic.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17  9:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:

> diff --git a/kernel/smp.c b/kernel/smp.c
> index c4d561cf50d45..44fa4b9b1f46b 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>  	arch_send_call_function_ipi_mask(mask);
>  }
>  
> +void smp_send_reschedule(int cpu)
> +{
> +	/* XXX scheduler_ipi is inline :/ */
> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> +	arch_smp_send_reschedule(cpu);
> +}
> +EXPORT_SYMBOL_GPL(smp_send_reschedule);

Yeah, no.. I see some crazy archs do this, but no we're not exporting
this in generic.

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17  9:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:

> diff --git a/kernel/smp.c b/kernel/smp.c
> index c4d561cf50d45..44fa4b9b1f46b 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>  	arch_send_call_function_ipi_mask(mask);
>  }
>  
> +void smp_send_reschedule(int cpu)
> +{
> +	/* XXX scheduler_ipi is inline :/ */
> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> +	arch_smp_send_reschedule(cpu);
> +}
> +EXPORT_SYMBOL_GPL(smp_send_reschedule);

Yeah, no.. I see some crazy archs do this, but no we're not exporting
this in generic.

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17  9:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Guo Ren,
	Paul E. McKenney, Steven Rostedt, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:

> diff --git a/kernel/smp.c b/kernel/smp.c
> index c4d561cf50d45..44fa4b9b1f46b 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>  	arch_send_call_function_ipi_mask(mask);
>  }
>  
> +void smp_send_reschedule(int cpu)
> +{
> +	/* XXX scheduler_ipi is inline :/ */
> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> +	arch_smp_send_reschedule(cpu);
> +}
> +EXPORT_SYMBOL_GPL(smp_send_reschedule);

Yeah, no.. I see some crazy archs do this, but no we're not exporting
this in generic.

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17  9:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Guo Ren,
	Paul E. McKenney, Steven Rostedt, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker

On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:

> diff --git a/kernel/smp.c b/kernel/smp.c
> index c4d561cf50d45..44fa4b9b1f46b 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>  	arch_send_call_function_ipi_mask(mask);
>  }
>  
> +void smp_send_reschedule(int cpu)
> +{
> +	/* XXX scheduler_ipi is inline :/ */
> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> +	arch_smp_send_reschedule(cpu);
> +}
> +EXPORT_SYMBOL_GPL(smp_send_reschedule);

Yeah, no.. I see some crazy archs do this, but no we're not exporting
this in generic.

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
  2022-11-02 18:33   ` Valentin Schneider
                       ` (5 preceding siblings ...)
  (?)
@ 2022-11-17 14:12     ` Peter Zijlstra
  -1 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17 14:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
> which so far has only been fed with NULL.
> 
> While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
> struct layout (meaning their callback func can be accessed without caring
> about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
> attached to its struct. This means we need to check the type of a CSD
> before eventually dereferencing its associated callback.
> 
> This isn't as trivial as it sounds: the CSD type is stored in
> __call_single_node.u_flags, which get cleared right before the callback is
> executed via csd_unlock(). This implies checking the CSD type before it is
> enqueued on the call_single_queue, as the target CPU's queue can be flushed
> before we get to sending an IPI.
> 
> Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
> would need to have an additional argument to trickle down the invoked
> function. This is somewhat silly, as the extra argument will always be
> pushed down to the function even when nothing is being traced, which is
> unnecessary overhead.
> 
> Two options present themselves:
> a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
>    an extra argument used for tracing, so that codepaths remain unchanged
>    when tracing isn't in effect (a sort of manual -fipa-sra).
> 
> b) Stash the CSD func in somewhere as a side effect that
>    the portion of send_call_function_{single_ipi, ipi_mask}() under the
>    tracepoint's static key can fetch.
> 
> a) creates redundant code, and b) is quite fragile due to requiring extra
> care for "reentrant" functions (async SMP calls).
> 
> This implements a).
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c   |  2 ++
>  kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
>  kernel/sched/smp.h  |  1 +
>  kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
>  4 files changed, 65 insertions(+), 15 deletions(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index aec38c294ce68..fcfa75c4a5daf 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>  
>  #include <trace/events/ipi.h>
>  
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 02181f8072b5f..41196ca67e913 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
>  	rq_unlock_irqrestore(rq, &rf);
>  }
>  
> -void send_call_function_single_ipi(int cpu)
> -{
> -	struct rq *rq = cpu_rq(cpu);
> -
> -	if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> -		arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> -	}
> -}
> +/*
> + * We want a variant that traces the function causing the IPI to be sent, but
> + * we don't want the extra argument to cause unnecessary overhead when tracing
> + * isn't happening.
> + */
> +#define GEN_CFSI(suffix, IPI_EXP, ...)						\
> +void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
> +{										\
> +	struct rq *rq = cpu_rq(cpu);						\
> +										\
> +	if (!set_nr_if_polling(rq->idle)) {					\
> +		IPI_EXP;							\
> +		arch_send_call_function_single_ipi(cpu);			\
> +	} else {								\
> +		trace_sched_wake_idle_without_ipi(cpu);				\
> +	}									\
> +}
> +
> +GEN_CFSI(/* nop */,
> +	 /* nop */,
> +	 int cpu)
> +GEN_CFSI(_trace,
> +	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
> +	 int cpu, smp_call_func_t func)
>  

*yuck*

How about something like so?

---
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
+bool send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
 	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
+		return true;
 	}
+
+	trace_sched_wake_idle_without_ipi(cpu);
+	return false;
 }
 
 /*
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -6,7 +6,7 @@
 
 extern void sched_ttwu_pending(void *arg);
 
-extern void send_call_function_single_ipi(int cpu);
+extern bool send_call_function_single_ipi(int cpu);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -163,7 +163,6 @@ void __init call_function_init(void)
 static inline void
 send_call_function_ipi_mask(const struct cpumask *mask)
 {
-	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
@@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
 		send_call_function_single_ipi(cpu);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
@@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
 
+static __always_inline
+bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
+{
+	/*
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
+	 *
+	 * If IPIs can go out of order to the cache coherency protocol
+	 * in an architecture, sufficient synchronisation should be added
+	 * to arch code to make it appear to obey cache coherency WRT
+	 * locking and barrier primitives. Generic code isn't really
+	 * equipped to do the right thing...
+	 */
+	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+		return send_call_function_single_ipi(cpu);
+
+	return false;
+}
+
 void __smp_call_single_queue(int cpu, struct llist_node *node)
 {
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
@@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
 #endif
 
 	/*
-	 * The list addition should be visible to the target CPU when it pops
-	 * the head of the list to pull the entry off it in the IPI handler
-	 * because of normal cache coherency rules implied by the underlying
-	 * llist ops.
-	 *
-	 * If IPIs can go out of order to the cache coherency protocol
-	 * in an architecture, sufficient synchronisation should be added
-	 * to arch code to make it appear to obey cache coherency WRT
-	 * locking and barrier primitives. Generic code isn't really
-	 * equipped to do the right thing...
-	 */
-	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
-		send_call_function_single_ipi(cpu);
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+
+		func = sched_ttwu_pending;
+		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
+			func = csd->func;
+
+		if (raw_smp_call_single_queue(cpu, node))
+			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
+		return;
+	}
+
+	raw_smp_call_single_queue(cpu, node);
 }
 
 /*
@@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
 		 * number of CPUs might be zero due to concurrent changes to the
 		 * provided mask.
 		 */
-		if (nr_cpus == 1)
+		if (nr_cpus == 1) {
+			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
 			send_call_function_single_ipi(last_cpu);
-		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+		} else if (likely(nr_cpus > 1)) {
+			trace_ipi_send_cpumask(mask, _RET_IP_, func);
+			send_call_function_ipi_mask(mask);
+		}
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17 14:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
> which so far has only been fed with NULL.
> 
> While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
> struct layout (meaning their callback func can be accessed without caring
> about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
> attached to its struct. This means we need to check the type of a CSD
> before eventually dereferencing its associated callback.
> 
> This isn't as trivial as it sounds: the CSD type is stored in
> __call_single_node.u_flags, which get cleared right before the callback is
> executed via csd_unlock(). This implies checking the CSD type before it is
> enqueued on the call_single_queue, as the target CPU's queue can be flushed
> before we get to sending an IPI.
> 
> Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
> would need to have an additional argument to trickle down the invoked
> function. This is somewhat silly, as the extra argument will always be
> pushed down to the function even when nothing is being traced, which is
> unnecessary overhead.
> 
> Two options present themselves:
> a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
>    an extra argument used for tracing, so that codepaths remain unchanged
>    when tracing isn't in effect (a sort of manual -fipa-sra).
> 
> b) Stash the CSD func in somewhere as a side effect that
>    the portion of send_call_function_{single_ipi, ipi_mask}() under the
>    tracepoint's static key can fetch.
> 
> a) creates redundant code, and b) is quite fragile due to requiring extra
> care for "reentrant" functions (async SMP calls).
> 
> This implements a).
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c   |  2 ++
>  kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
>  kernel/sched/smp.h  |  1 +
>  kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
>  4 files changed, 65 insertions(+), 15 deletions(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index aec38c294ce68..fcfa75c4a5daf 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>  
>  #include <trace/events/ipi.h>
>  
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 02181f8072b5f..41196ca67e913 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
>  	rq_unlock_irqrestore(rq, &rf);
>  }
>  
> -void send_call_function_single_ipi(int cpu)
> -{
> -	struct rq *rq = cpu_rq(cpu);
> -
> -	if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> -		arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> -	}
> -}
> +/*
> + * We want a variant that traces the function causing the IPI to be sent, but
> + * we don't want the extra argument to cause unnecessary overhead when tracing
> + * isn't happening.
> + */
> +#define GEN_CFSI(suffix, IPI_EXP, ...)						\
> +void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
> +{										\
> +	struct rq *rq = cpu_rq(cpu);						\
> +										\
> +	if (!set_nr_if_polling(rq->idle)) {					\
> +		IPI_EXP;							\
> +		arch_send_call_function_single_ipi(cpu);			\
> +	} else {								\
> +		trace_sched_wake_idle_without_ipi(cpu);				\
> +	}									\
> +}
> +
> +GEN_CFSI(/* nop */,
> +	 /* nop */,
> +	 int cpu)
> +GEN_CFSI(_trace,
> +	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
> +	 int cpu, smp_call_func_t func)
>  

*yuck*

How about something like so?

---
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
+bool send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
 	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
+		return true;
 	}
+
+	trace_sched_wake_idle_without_ipi(cpu);
+	return false;
 }
 
 /*
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -6,7 +6,7 @@
 
 extern void sched_ttwu_pending(void *arg);
 
-extern void send_call_function_single_ipi(int cpu);
+extern bool send_call_function_single_ipi(int cpu);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -163,7 +163,6 @@ void __init call_function_init(void)
 static inline void
 send_call_function_ipi_mask(const struct cpumask *mask)
 {
-	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
@@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
 		send_call_function_single_ipi(cpu);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
@@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
 
+static __always_inline
+bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
+{
+	/*
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
+	 *
+	 * If IPIs can go out of order to the cache coherency protocol
+	 * in an architecture, sufficient synchronisation should be added
+	 * to arch code to make it appear to obey cache coherency WRT
+	 * locking and barrier primitives. Generic code isn't really
+	 * equipped to do the right thing...
+	 */
+	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+		return send_call_function_single_ipi(cpu);
+
+	return false;
+}
+
 void __smp_call_single_queue(int cpu, struct llist_node *node)
 {
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
@@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
 #endif
 
 	/*
-	 * The list addition should be visible to the target CPU when it pops
-	 * the head of the list to pull the entry off it in the IPI handler
-	 * because of normal cache coherency rules implied by the underlying
-	 * llist ops.
-	 *
-	 * If IPIs can go out of order to the cache coherency protocol
-	 * in an architecture, sufficient synchronisation should be added
-	 * to arch code to make it appear to obey cache coherency WRT
-	 * locking and barrier primitives. Generic code isn't really
-	 * equipped to do the right thing...
-	 */
-	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
-		send_call_function_single_ipi(cpu);
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+
+		func = sched_ttwu_pending;
+		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
+			func = csd->func;
+
+		if (raw_smp_call_single_queue(cpu, node))
+			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
+		return;
+	}
+
+	raw_smp_call_single_queue(cpu, node);
 }
 
 /*
@@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
 		 * number of CPUs might be zero due to concurrent changes to the
 		 * provided mask.
 		 */
-		if (nr_cpus == 1)
+		if (nr_cpus == 1) {
+			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
 			send_call_function_single_ipi(last_cpu);
-		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+		} else if (likely(nr_cpus > 1)) {
+			trace_ipi_send_cpumask(mask, _RET_IP_, func);
+			send_call_function_ipi_mask(mask);
+		}
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}

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^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17 14:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
> which so far has only been fed with NULL.
> 
> While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
> struct layout (meaning their callback func can be accessed without caring
> about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
> attached to its struct. This means we need to check the type of a CSD
> before eventually dereferencing its associated callback.
> 
> This isn't as trivial as it sounds: the CSD type is stored in
> __call_single_node.u_flags, which get cleared right before the callback is
> executed via csd_unlock(). This implies checking the CSD type before it is
> enqueued on the call_single_queue, as the target CPU's queue can be flushed
> before we get to sending an IPI.
> 
> Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
> would need to have an additional argument to trickle down the invoked
> function. This is somewhat silly, as the extra argument will always be
> pushed down to the function even when nothing is being traced, which is
> unnecessary overhead.
> 
> Two options present themselves:
> a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
>    an extra argument used for tracing, so that codepaths remain unchanged
>    when tracing isn't in effect (a sort of manual -fipa-sra).
> 
> b) Stash the CSD func in somewhere as a side effect that
>    the portion of send_call_function_{single_ipi, ipi_mask}() under the
>    tracepoint's static key can fetch.
> 
> a) creates redundant code, and b) is quite fragile due to requiring extra
> care for "reentrant" functions (async SMP calls).
> 
> This implements a).
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c   |  2 ++
>  kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
>  kernel/sched/smp.h  |  1 +
>  kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
>  4 files changed, 65 insertions(+), 15 deletions(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index aec38c294ce68..fcfa75c4a5daf 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>  
>  #include <trace/events/ipi.h>
>  
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 02181f8072b5f..41196ca67e913 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
>  	rq_unlock_irqrestore(rq, &rf);
>  }
>  
> -void send_call_function_single_ipi(int cpu)
> -{
> -	struct rq *rq = cpu_rq(cpu);
> -
> -	if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> -		arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> -	}
> -}
> +/*
> + * We want a variant that traces the function causing the IPI to be sent, but
> + * we don't want the extra argument to cause unnecessary overhead when tracing
> + * isn't happening.
> + */
> +#define GEN_CFSI(suffix, IPI_EXP, ...)						\
> +void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
> +{										\
> +	struct rq *rq = cpu_rq(cpu);						\
> +										\
> +	if (!set_nr_if_polling(rq->idle)) {					\
> +		IPI_EXP;							\
> +		arch_send_call_function_single_ipi(cpu);			\
> +	} else {								\
> +		trace_sched_wake_idle_without_ipi(cpu);				\
> +	}									\
> +}
> +
> +GEN_CFSI(/* nop */,
> +	 /* nop */,
> +	 int cpu)
> +GEN_CFSI(_trace,
> +	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
> +	 int cpu, smp_call_func_t func)
>  

*yuck*

How about something like so?

---
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
+bool send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
 	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
+		return true;
 	}
+
+	trace_sched_wake_idle_without_ipi(cpu);
+	return false;
 }
 
 /*
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -6,7 +6,7 @@
 
 extern void sched_ttwu_pending(void *arg);
 
-extern void send_call_function_single_ipi(int cpu);
+extern bool send_call_function_single_ipi(int cpu);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -163,7 +163,6 @@ void __init call_function_init(void)
 static inline void
 send_call_function_ipi_mask(const struct cpumask *mask)
 {
-	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
@@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
 		send_call_function_single_ipi(cpu);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
@@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
 
+static __always_inline
+bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
+{
+	/*
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
+	 *
+	 * If IPIs can go out of order to the cache coherency protocol
+	 * in an architecture, sufficient synchronisation should be added
+	 * to arch code to make it appear to obey cache coherency WRT
+	 * locking and barrier primitives. Generic code isn't really
+	 * equipped to do the right thing...
+	 */
+	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+		return send_call_function_single_ipi(cpu);
+
+	return false;
+}
+
 void __smp_call_single_queue(int cpu, struct llist_node *node)
 {
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
@@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
 #endif
 
 	/*
-	 * The list addition should be visible to the target CPU when it pops
-	 * the head of the list to pull the entry off it in the IPI handler
-	 * because of normal cache coherency rules implied by the underlying
-	 * llist ops.
-	 *
-	 * If IPIs can go out of order to the cache coherency protocol
-	 * in an architecture, sufficient synchronisation should be added
-	 * to arch code to make it appear to obey cache coherency WRT
-	 * locking and barrier primitives. Generic code isn't really
-	 * equipped to do the right thing...
-	 */
-	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
-		send_call_function_single_ipi(cpu);
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+
+		func = sched_ttwu_pending;
+		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
+			func = csd->func;
+
+		if (raw_smp_call_single_queue(cpu, node))
+			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
+		return;
+	}
+
+	raw_smp_call_single_queue(cpu, node);
 }
 
 /*
@@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
 		 * number of CPUs might be zero due to concurrent changes to the
 		 * provided mask.
 		 */
-		if (nr_cpus == 1)
+		if (nr_cpus == 1) {
+			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
 			send_call_function_single_ipi(last_cpu);
-		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+		} else if (likely(nr_cpus > 1)) {
+			trace_ipi_send_cpumask(mask, _RET_IP_, func);
+			send_call_function_ipi_mask(mask);
+		}
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}

_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17 14:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
> which so far has only been fed with NULL.
> 
> While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
> struct layout (meaning their callback func can be accessed without caring
> about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
> attached to its struct. This means we need to check the type of a CSD
> before eventually dereferencing its associated callback.
> 
> This isn't as trivial as it sounds: the CSD type is stored in
> __call_single_node.u_flags, which get cleared right before the callback is
> executed via csd_unlock(). This implies checking the CSD type before it is
> enqueued on the call_single_queue, as the target CPU's queue can be flushed
> before we get to sending an IPI.
> 
> Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
> would need to have an additional argument to trickle down the invoked
> function. This is somewhat silly, as the extra argument will always be
> pushed down to the function even when nothing is being traced, which is
> unnecessary overhead.
> 
> Two options present themselves:
> a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
>    an extra argument used for tracing, so that codepaths remain unchanged
>    when tracing isn't in effect (a sort of manual -fipa-sra).
> 
> b) Stash the CSD func in somewhere as a side effect that
>    the portion of send_call_function_{single_ipi, ipi_mask}() under the
>    tracepoint's static key can fetch.
> 
> a) creates redundant code, and b) is quite fragile due to requiring extra
> care for "reentrant" functions (async SMP calls).
> 
> This implements a).
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c   |  2 ++
>  kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
>  kernel/sched/smp.h  |  1 +
>  kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
>  4 files changed, 65 insertions(+), 15 deletions(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index aec38c294ce68..fcfa75c4a5daf 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>  
>  #include <trace/events/ipi.h>
>  
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 02181f8072b5f..41196ca67e913 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
>  	rq_unlock_irqrestore(rq, &rf);
>  }
>  
> -void send_call_function_single_ipi(int cpu)
> -{
> -	struct rq *rq = cpu_rq(cpu);
> -
> -	if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> -		arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> -	}
> -}
> +/*
> + * We want a variant that traces the function causing the IPI to be sent, but
> + * we don't want the extra argument to cause unnecessary overhead when tracing
> + * isn't happening.
> + */
> +#define GEN_CFSI(suffix, IPI_EXP, ...)						\
> +void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
> +{										\
> +	struct rq *rq = cpu_rq(cpu);						\
> +										\
> +	if (!set_nr_if_polling(rq->idle)) {					\
> +		IPI_EXP;							\
> +		arch_send_call_function_single_ipi(cpu);			\
> +	} else {								\
> +		trace_sched_wake_idle_without_ipi(cpu);				\
> +	}									\
> +}
> +
> +GEN_CFSI(/* nop */,
> +	 /* nop */,
> +	 int cpu)
> +GEN_CFSI(_trace,
> +	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
> +	 int cpu, smp_call_func_t func)
>  

*yuck*

How about something like so?

---
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
+bool send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
 	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
+		return true;
 	}
+
+	trace_sched_wake_idle_without_ipi(cpu);
+	return false;
 }
 
 /*
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -6,7 +6,7 @@
 
 extern void sched_ttwu_pending(void *arg);
 
-extern void send_call_function_single_ipi(int cpu);
+extern bool send_call_function_single_ipi(int cpu);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -163,7 +163,6 @@ void __init call_function_init(void)
 static inline void
 send_call_function_ipi_mask(const struct cpumask *mask)
 {
-	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
@@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
 		send_call_function_single_ipi(cpu);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
@@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
 
+static __always_inline
+bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
+{
+	/*
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
+	 *
+	 * If IPIs can go out of order to the cache coherency protocol
+	 * in an architecture, sufficient synchronisation should be added
+	 * to arch code to make it appear to obey cache coherency WRT
+	 * locking and barrier primitives. Generic code isn't really
+	 * equipped to do the right thing...
+	 */
+	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+		return send_call_function_single_ipi(cpu);
+
+	return false;
+}
+
 void __smp_call_single_queue(int cpu, struct llist_node *node)
 {
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
@@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
 #endif
 
 	/*
-	 * The list addition should be visible to the target CPU when it pops
-	 * the head of the list to pull the entry off it in the IPI handler
-	 * because of normal cache coherency rules implied by the underlying
-	 * llist ops.
-	 *
-	 * If IPIs can go out of order to the cache coherency protocol
-	 * in an architecture, sufficient synchronisation should be added
-	 * to arch code to make it appear to obey cache coherency WRT
-	 * locking and barrier primitives. Generic code isn't really
-	 * equipped to do the right thing...
-	 */
-	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
-		send_call_function_single_ipi(cpu);
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+
+		func = sched_ttwu_pending;
+		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
+			func = csd->func;
+
+		if (raw_smp_call_single_queue(cpu, node))
+			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
+		return;
+	}
+
+	raw_smp_call_single_queue(cpu, node);
 }
 
 /*
@@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
 		 * number of CPUs might be zero due to concurrent changes to the
 		 * provided mask.
 		 */
-		if (nr_cpus == 1)
+		if (nr_cpus == 1) {
+			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
 			send_call_function_single_ipi(last_cpu);
-		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+		} else if (likely(nr_cpus > 1)) {
+			trace_ipi_send_cpumask(mask, _RET_IP_, func);
+			send_call_function_ipi_mask(mask);
+		}
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17 14:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
> which so far has only been fed with NULL.
> 
> While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
> struct layout (meaning their callback func can be accessed without caring
> about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
> attached to its struct. This means we need to check the type of a CSD
> before eventually dereferencing its associated callback.
> 
> This isn't as trivial as it sounds: the CSD type is stored in
> __call_single_node.u_flags, which get cleared right before the callback is
> executed via csd_unlock(). This implies checking the CSD type before it is
> enqueued on the call_single_queue, as the target CPU's queue can be flushed
> before we get to sending an IPI.
> 
> Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
> would need to have an additional argument to trickle down the invoked
> function. This is somewhat silly, as the extra argument will always be
> pushed down to the function even when nothing is being traced, which is
> unnecessary overhead.
> 
> Two options present themselves:
> a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
>    an extra argument used for tracing, so that codepaths remain unchanged
>    when tracing isn't in effect (a sort of manual -fipa-sra).
> 
> b) Stash the CSD func in somewhere as a side effect that
>    the portion of send_call_function_{single_ipi, ipi_mask}() under the
>    tracepoint's static key can fetch.
> 
> a) creates redundant code, and b) is quite fragile due to requiring extra
> care for "reentrant" functions (async SMP calls).
> 
> This implements a).
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c   |  2 ++
>  kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
>  kernel/sched/smp.h  |  1 +
>  kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
>  4 files changed, 65 insertions(+), 15 deletions(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index aec38c294ce68..fcfa75c4a5daf 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>  
>  #include <trace/events/ipi.h>
>  
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 02181f8072b5f..41196ca67e913 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
>  	rq_unlock_irqrestore(rq, &rf);
>  }
>  
> -void send_call_function_single_ipi(int cpu)
> -{
> -	struct rq *rq = cpu_rq(cpu);
> -
> -	if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> -		arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> -	}
> -}
> +/*
> + * We want a variant that traces the function causing the IPI to be sent, but
> + * we don't want the extra argument to cause unnecessary overhead when tracing
> + * isn't happening.
> + */
> +#define GEN_CFSI(suffix, IPI_EXP, ...)						\
> +void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
> +{										\
> +	struct rq *rq = cpu_rq(cpu);						\
> +										\
> +	if (!set_nr_if_polling(rq->idle)) {					\
> +		IPI_EXP;							\
> +		arch_send_call_function_single_ipi(cpu);			\
> +	} else {								\
> +		trace_sched_wake_idle_without_ipi(cpu);				\
> +	}									\
> +}
> +
> +GEN_CFSI(/* nop */,
> +	 /* nop */,
> +	 int cpu)
> +GEN_CFSI(_trace,
> +	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
> +	 int cpu, smp_call_func_t func)
>  

*yuck*

How about something like so?

---
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
+bool send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
 	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
+		return true;
 	}
+
+	trace_sched_wake_idle_without_ipi(cpu);
+	return false;
 }
 
 /*
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -6,7 +6,7 @@
 
 extern void sched_ttwu_pending(void *arg);
 
-extern void send_call_function_single_ipi(int cpu);
+extern bool send_call_function_single_ipi(int cpu);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -163,7 +163,6 @@ void __init call_function_init(void)
 static inline void
 send_call_function_ipi_mask(const struct cpumask *mask)
 {
-	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
@@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
 		send_call_function_single_ipi(cpu);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
@@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
 
+static __always_inline
+bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
+{
+	/*
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
+	 *
+	 * If IPIs can go out of order to the cache coherency protocol
+	 * in an architecture, sufficient synchronisation should be added
+	 * to arch code to make it appear to obey cache coherency WRT
+	 * locking and barrier primitives. Generic code isn't really
+	 * equipped to do the right thing...
+	 */
+	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+		return send_call_function_single_ipi(cpu);
+
+	return false;
+}
+
 void __smp_call_single_queue(int cpu, struct llist_node *node)
 {
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
@@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
 #endif
 
 	/*
-	 * The list addition should be visible to the target CPU when it pops
-	 * the head of the list to pull the entry off it in the IPI handler
-	 * because of normal cache coherency rules implied by the underlying
-	 * llist ops.
-	 *
-	 * If IPIs can go out of order to the cache coherency protocol
-	 * in an architecture, sufficient synchronisation should be added
-	 * to arch code to make it appear to obey cache coherency WRT
-	 * locking and barrier primitives. Generic code isn't really
-	 * equipped to do the right thing...
-	 */
-	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
-		send_call_function_single_ipi(cpu);
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+
+		func = sched_ttwu_pending;
+		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
+			func = csd->func;
+
+		if (raw_smp_call_single_queue(cpu, node))
+			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
+		return;
+	}
+
+	raw_smp_call_single_queue(cpu, node);
 }
 
 /*
@@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
 		 * number of CPUs might be zero due to concurrent changes to the
 		 * provided mask.
 		 */
-		if (nr_cpus == 1)
+		if (nr_cpus == 1) {
+			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
 			send_call_function_single_ipi(last_cpu);
-		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+		} else if (likely(nr_cpus > 1)) {
+			trace_ipi_send_cpumask(mask, _RET_IP_, func);
+			send_call_function_ipi_mask(mask);
+		}
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17 14:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
> which so far has only been fed with NULL.
> 
> While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
> struct layout (meaning their callback func can be accessed without caring
> about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
> attached to its struct. This means we need to check the type of a CSD
> before eventually dereferencing its associated callback.
> 
> This isn't as trivial as it sounds: the CSD type is stored in
> __call_single_node.u_flags, which get cleared right before the callback is
> executed via csd_unlock(). This implies checking the CSD type before it is
> enqueued on the call_single_queue, as the target CPU's queue can be flushed
> before we get to sending an IPI.
> 
> Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
> would need to have an additional argument to trickle down the invoked
> function. This is somewhat silly, as the extra argument will always be
> pushed down to the function even when nothing is being traced, which is
> unnecessary overhead.
> 
> Two options present themselves:
> a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
>    an extra argument used for tracing, so that codepaths remain unchanged
>    when tracing isn't in effect (a sort of manual -fipa-sra).
> 
> b) Stash the CSD func in somewhere as a side effect that
>    the portion of send_call_function_{single_ipi, ipi_mask}() under the
>    tracepoint's static key can fetch.
> 
> a) creates redundant code, and b) is quite fragile due to requiring extra
> care for "reentrant" functions (async SMP calls).
> 
> This implements a).
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c   |  2 ++
>  kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
>  kernel/sched/smp.h  |  1 +
>  kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
>  4 files changed, 65 insertions(+), 15 deletions(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index aec38c294ce68..fcfa75c4a5daf 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>  
>  #include <trace/events/ipi.h>
>  
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 02181f8072b5f..41196ca67e913 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
>  	rq_unlock_irqrestore(rq, &rf);
>  }
>  
> -void send_call_function_single_ipi(int cpu)
> -{
> -	struct rq *rq = cpu_rq(cpu);
> -
> -	if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> -		arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> -	}
> -}
> +/*
> + * We want a variant that traces the function causing the IPI to be sent, but
> + * we don't want the extra argument to cause unnecessary overhead when tracing
> + * isn't happening.
> + */
> +#define GEN_CFSI(suffix, IPI_EXP, ...)						\
> +void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
> +{										\
> +	struct rq *rq = cpu_rq(cpu);						\
> +										\
> +	if (!set_nr_if_polling(rq->idle)) {					\
> +		IPI_EXP;							\
> +		arch_send_call_function_single_ipi(cpu);			\
> +	} else {								\
> +		trace_sched_wake_idle_without_ipi(cpu);				\
> +	}									\
> +}
> +
> +GEN_CFSI(/* nop */,
> +	 /* nop */,
> +	 int cpu)
> +GEN_CFSI(_trace,
> +	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
> +	 int cpu, smp_call_func_t func)
>  

*yuck*

How about something like so?

---
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
+bool send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
 	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
+		return true;
 	}
+
+	trace_sched_wake_idle_without_ipi(cpu);
+	return false;
 }
 
 /*
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -6,7 +6,7 @@
 
 extern void sched_ttwu_pending(void *arg);
 
-extern void send_call_function_single_ipi(int cpu);
+extern bool send_call_function_single_ipi(int cpu);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -163,7 +163,6 @@ void __init call_function_init(void)
 static inline void
 send_call_function_ipi_mask(const struct cpumask *mask)
 {
-	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
@@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
 		send_call_function_single_ipi(cpu);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
@@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
 
+static __always_inline
+bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
+{
+	/*
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
+	 *
+	 * If IPIs can go out of order to the cache coherency protocol
+	 * in an architecture, sufficient synchronisation should be added
+	 * to arch code to make it appear to obey cache coherency WRT
+	 * locking and barrier primitives. Generic code isn't really
+	 * equipped to do the right thing...
+	 */
+	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+		return send_call_function_single_ipi(cpu);
+
+	return false;
+}
+
 void __smp_call_single_queue(int cpu, struct llist_node *node)
 {
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
@@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
 #endif
 
 	/*
-	 * The list addition should be visible to the target CPU when it pops
-	 * the head of the list to pull the entry off it in the IPI handler
-	 * because of normal cache coherency rules implied by the underlying
-	 * llist ops.
-	 *
-	 * If IPIs can go out of order to the cache coherency protocol
-	 * in an architecture, sufficient synchronisation should be added
-	 * to arch code to make it appear to obey cache coherency WRT
-	 * locking and barrier primitives. Generic code isn't really
-	 * equipped to do the right thing...
-	 */
-	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
-		send_call_function_single_ipi(cpu);
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+
+		func = sched_ttwu_pending;
+		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
+			func = csd->func;
+
+		if (raw_smp_call_single_queue(cpu, node))
+			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
+		return;
+	}
+
+	raw_smp_call_single_queue(cpu, node);
 }
 
 /*
@@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
 		 * number of CPUs might be zero due to concurrent changes to the
 		 * provided mask.
 		 */
-		if (nr_cpus == 1)
+		if (nr_cpus == 1) {
+			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
 			send_call_function_single_ipi(last_cpu);
-		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+		} else if (likely(nr_cpus > 1)) {
+			trace_ipi_send_cpumask(mask, _RET_IP_, func);
+			send_call_function_ipi_mask(mask);
+		}
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}

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^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17 14:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
> which so far has only been fed with NULL.
> 
> While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
> struct layout (meaning their callback func can be accessed without caring
> about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
> attached to its struct. This means we need to check the type of a CSD
> before eventually dereferencing its associated callback.
> 
> This isn't as trivial as it sounds: the CSD type is stored in
> __call_single_node.u_flags, which get cleared right before the callback is
> executed via csd_unlock(). This implies checking the CSD type before it is
> enqueued on the call_single_queue, as the target CPU's queue can be flushed
> before we get to sending an IPI.
> 
> Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
> would need to have an additional argument to trickle down the invoked
> function. This is somewhat silly, as the extra argument will always be
> pushed down to the function even when nothing is being traced, which is
> unnecessary overhead.
> 
> Two options present themselves:
> a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
>    an extra argument used for tracing, so that codepaths remain unchanged
>    when tracing isn't in effect (a sort of manual -fipa-sra).
> 
> b) Stash the CSD func in somewhere as a side effect that
>    the portion of send_call_function_{single_ipi, ipi_mask}() under the
>    tracepoint's static key can fetch.
> 
> a) creates redundant code, and b) is quite fragile due to requiring extra
> care for "reentrant" functions (async SMP calls).
> 
> This implements a).
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c   |  2 ++
>  kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
>  kernel/sched/smp.h  |  1 +
>  kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
>  4 files changed, 65 insertions(+), 15 deletions(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index aec38c294ce68..fcfa75c4a5daf 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>  
>  #include <trace/events/ipi.h>
>  
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 02181f8072b5f..41196ca67e913 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
>  	rq_unlock_irqrestore(rq, &rf);
>  }
>  
> -void send_call_function_single_ipi(int cpu)
> -{
> -	struct rq *rq = cpu_rq(cpu);
> -
> -	if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> -		arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> -	}
> -}
> +/*
> + * We want a variant that traces the function causing the IPI to be sent, but
> + * we don't want the extra argument to cause unnecessary overhead when tracing
> + * isn't happening.
> + */
> +#define GEN_CFSI(suffix, IPI_EXP, ...)						\
> +void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
> +{										\
> +	struct rq *rq = cpu_rq(cpu);						\
> +										\
> +	if (!set_nr_if_polling(rq->idle)) {					\
> +		IPI_EXP;							\
> +		arch_send_call_function_single_ipi(cpu);			\
> +	} else {								\
> +		trace_sched_wake_idle_without_ipi(cpu);				\
> +	}									\
> +}
> +
> +GEN_CFSI(/* nop */,
> +	 /* nop */,
> +	 int cpu)
> +GEN_CFSI(_trace,
> +	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
> +	 int cpu, smp_call_func_t func)
>  

*yuck*

How about something like so?

---
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
+bool send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
 	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
+		return true;
 	}
+
+	trace_sched_wake_idle_without_ipi(cpu);
+	return false;
 }
 
 /*
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -6,7 +6,7 @@
 
 extern void sched_ttwu_pending(void *arg);
 
-extern void send_call_function_single_ipi(int cpu);
+extern bool send_call_function_single_ipi(int cpu);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -163,7 +163,6 @@ void __init call_function_init(void)
 static inline void
 send_call_function_ipi_mask(const struct cpumask *mask)
 {
-	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
@@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
 		send_call_function_single_ipi(cpu);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
@@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
 
+static __always_inline
+bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
+{
+	/*
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
+	 *
+	 * If IPIs can go out of order to the cache coherency protocol
+	 * in an architecture, sufficient synchronisation should be added
+	 * to arch code to make it appear to obey cache coherency WRT
+	 * locking and barrier primitives. Generic code isn't really
+	 * equipped to do the right thing...
+	 */
+	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+		return send_call_function_single_ipi(cpu);
+
+	return false;
+}
+
 void __smp_call_single_queue(int cpu, struct llist_node *node)
 {
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
@@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
 #endif
 
 	/*
-	 * The list addition should be visible to the target CPU when it pops
-	 * the head of the list to pull the entry off it in the IPI handler
-	 * because of normal cache coherency rules implied by the underlying
-	 * llist ops.
-	 *
-	 * If IPIs can go out of order to the cache coherency protocol
-	 * in an architecture, sufficient synchronisation should be added
-	 * to arch code to make it appear to obey cache coherency WRT
-	 * locking and barrier primitives. Generic code isn't really
-	 * equipped to do the right thing...
-	 */
-	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
-		send_call_function_single_ipi(cpu);
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+
+		func = sched_ttwu_pending;
+		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
+			func = csd->func;
+
+		if (raw_smp_call_single_queue(cpu, node))
+			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
+		return;
+	}
+
+	raw_smp_call_single_queue(cpu, node);
 }
 
 /*
@@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
 		 * number of CPUs might be zero due to concurrent changes to the
 		 * provided mask.
 		 */
-		if (nr_cpus = 1)
+		if (nr_cpus = 1) {
+			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
 			send_call_function_single_ipi(last_cpu);
-		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+		} else if (likely(nr_cpus > 1)) {
+			trace_ipi_send_cpumask(mask, _RET_IP_, func);
+			send_call_function_ipi_mask(mask);
+		}
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:12     ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-17 14:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar

On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> The newly-introduced ipi_send_cpumask tracepoint has a "callback" parameter
> which so far has only been fed with NULL.
> 
> While CSD_TYPE_SYNC/ASYNC and CSD_TYPE_IRQ_WORK share a similar backing
> struct layout (meaning their callback func can be accessed without caring
> about the actual CSD type), CSD_TYPE_TTWU doesn't even have a function
> attached to its struct. This means we need to check the type of a CSD
> before eventually dereferencing its associated callback.
> 
> This isn't as trivial as it sounds: the CSD type is stored in
> __call_single_node.u_flags, which get cleared right before the callback is
> executed via csd_unlock(). This implies checking the CSD type before it is
> enqueued on the call_single_queue, as the target CPU's queue can be flushed
> before we get to sending an IPI.
> 
> Furthermore, send_call_function_single_ipi() only has a CPU parameter, and
> would need to have an additional argument to trickle down the invoked
> function. This is somewhat silly, as the extra argument will always be
> pushed down to the function even when nothing is being traced, which is
> unnecessary overhead.
> 
> Two options present themselves:
> a) Create copies of send_call_function_{single_ipi, ipi_mask}() that take
>    an extra argument used for tracing, so that codepaths remain unchanged
>    when tracing isn't in effect (a sort of manual -fipa-sra).
> 
> b) Stash the CSD func in somewhere as a side effect that
>    the portion of send_call_function_{single_ipi, ipi_mask}() under the
>    tracepoint's static key can fetch.
> 
> a) creates redundant code, and b) is quite fragile due to requiring extra
> care for "reentrant" functions (async SMP calls).
> 
> This implements a).
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> ---
>  kernel/irq_work.c   |  2 ++
>  kernel/sched/core.c | 35 ++++++++++++++++++++++++-----------
>  kernel/sched/smp.h  |  1 +
>  kernel/smp.c        | 42 ++++++++++++++++++++++++++++++++++++++----
>  4 files changed, 65 insertions(+), 15 deletions(-)
> 
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index aec38c294ce68..fcfa75c4a5daf 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>  
>  #include <trace/events/ipi.h>
>  
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 02181f8072b5f..41196ca67e913 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3743,17 +3743,30 @@ void sched_ttwu_pending(void *arg)
>  	rq_unlock_irqrestore(rq, &rf);
>  }
>  
> -void send_call_function_single_ipi(int cpu)
> -{
> -	struct rq *rq = cpu_rq(cpu);
> -
> -	if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> -		arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> -	}
> -}
> +/*
> + * We want a variant that traces the function causing the IPI to be sent, but
> + * we don't want the extra argument to cause unnecessary overhead when tracing
> + * isn't happening.
> + */
> +#define GEN_CFSI(suffix, IPI_EXP, ...)						\
> +void send_call_function_single_ipi##suffix(__VA_ARGS__)				\
> +{										\
> +	struct rq *rq = cpu_rq(cpu);						\
> +										\
> +	if (!set_nr_if_polling(rq->idle)) {					\
> +		IPI_EXP;							\
> +		arch_send_call_function_single_ipi(cpu);			\
> +	} else {								\
> +		trace_sched_wake_idle_without_ipi(cpu);				\
> +	}									\
> +}
> +
> +GEN_CFSI(/* nop */,
> +	 /* nop */,
> +	 int cpu)
> +GEN_CFSI(_trace,
> +	 trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func),
> +	 int cpu, smp_call_func_t func)
>  

*yuck*

How about something like so?

---
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -24,6 +24,8 @@
 
 #include <trace/events/ipi.h>
 
+#include "sched/smp.h"
+
 static DEFINE_PER_CPU(struct llist_head, raised_list);
 static DEFINE_PER_CPU(struct llist_head, lazy_list);
 static DEFINE_PER_CPU(struct task_struct *, irq_workd);
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
 	rq_unlock_irqrestore(rq, &rf);
 }
 
-void send_call_function_single_ipi(int cpu)
+bool send_call_function_single_ipi(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 
 	if (!set_nr_if_polling(rq->idle)) {
-		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
 		arch_send_call_function_single_ipi(cpu);
-	} else {
-		trace_sched_wake_idle_without_ipi(cpu);
+		return true;
 	}
+
+	trace_sched_wake_idle_without_ipi(cpu);
+	return false;
 }
 
 /*
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -6,7 +6,7 @@
 
 extern void sched_ttwu_pending(void *arg);
 
-extern void send_call_function_single_ipi(int cpu);
+extern bool send_call_function_single_ipi(int cpu);
 
 #ifdef CONFIG_SMP
 extern void flush_smp_call_function_queue(void);
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -163,7 +163,6 @@ void __init call_function_init(void)
 static inline void
 send_call_function_ipi_mask(const struct cpumask *mask)
 {
-	trace_ipi_send_cpumask(mask, _RET_IP_, func);
 	arch_send_call_function_ipi_mask(mask);
 }
 
@@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
 	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
 	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
 	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	struct __call_single_data *csd;
+
+	csd = container_of(node, call_single_data_t, node.llist);
+	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
 
 	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
 	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
 		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
 		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
+		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
 		send_call_function_single_ipi(cpu);
 		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
 	} else {
@@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
 
+static __always_inline
+bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
+{
+	/*
+	 * The list addition should be visible to the target CPU when it pops
+	 * the head of the list to pull the entry off it in the IPI handler
+	 * because of normal cache coherency rules implied by the underlying
+	 * llist ops.
+	 *
+	 * If IPIs can go out of order to the cache coherency protocol
+	 * in an architecture, sufficient synchronisation should be added
+	 * to arch code to make it appear to obey cache coherency WRT
+	 * locking and barrier primitives. Generic code isn't really
+	 * equipped to do the right thing...
+	 */
+	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+		return send_call_function_single_ipi(cpu);
+
+	return false;
+}
+
 void __smp_call_single_queue(int cpu, struct llist_node *node)
 {
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
@@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
 #endif
 
 	/*
-	 * The list addition should be visible to the target CPU when it pops
-	 * the head of the list to pull the entry off it in the IPI handler
-	 * because of normal cache coherency rules implied by the underlying
-	 * llist ops.
-	 *
-	 * If IPIs can go out of order to the cache coherency protocol
-	 * in an architecture, sufficient synchronisation should be added
-	 * to arch code to make it appear to obey cache coherency WRT
-	 * locking and barrier primitives. Generic code isn't really
-	 * equipped to do the right thing...
-	 */
-	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
-		send_call_function_single_ipi(cpu);
+	 * We have to check the type of the CSD before queueing it, because
+	 * once queued it can have its flags cleared by
+	 *   flush_smp_call_function_queue()
+	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+	 * executes migration_cpu_stop() on the remote CPU).
+	 */
+	if (trace_ipi_send_cpumask_enabled()) {
+		call_single_data_t *csd;
+		smp_call_func_t func;
+
+		csd = container_of(node, call_single_data_t, node.llist);
+
+		func = sched_ttwu_pending;
+		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
+			func = csd->func;
+
+		if (raw_smp_call_single_queue(cpu, node))
+			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
+		return;
+	}
+
+	raw_smp_call_single_queue(cpu, node);
 }
 
 /*
@@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
 		 * number of CPUs might be zero due to concurrent changes to the
 		 * provided mask.
 		 */
-		if (nr_cpus == 1)
+		if (nr_cpus == 1) {
+			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
 			send_call_function_single_ipi(last_cpu);
-		else if (likely(nr_cpus > 1))
-			send_call_function_ipi_mask(cfd->cpumask_ipi);
+		} else if (likely(nr_cpus > 1)) {
+			trace_ipi_send_cpumask(mask, _RET_IP_, func);
+			send_call_function_ipi_mask(mask);
+		}
 
 		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
 	}

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
  2022-11-17  9:08     ` Peter Zijlstra
                         ` (4 preceding siblings ...)
  (?)
@ 2022-11-17 14:23       ` Valentin Schneider
  -1 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:23 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On 17/11/22 10:08, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
>> This simply wraps around the arch function and prepends it with a
>> tracepoint, similar to send_call_function_single_ipi().
>>
>> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
>> ---
>>  kernel/smp.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index e2ca1e2f31274..c4d561cf50d45 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>>      smpcfd_prepare_cpu(smp_processor_id());
>>  }
>>
>> +static inline void
>
> Given the use of _RET_IP_, I would strongly recommend you use
> __always_inline.
>

Noted, thanks

>> +send_call_function_ipi_mask(const struct cpumask *mask)
>> +{
>> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>
> What's func?
>

A rebase fail... That's only plugged in later.

>> +	arch_send_call_function_ipi_mask(mask);
>> +}


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17 14:23       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:23 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On 17/11/22 10:08, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
>> This simply wraps around the arch function and prepends it with a
>> tracepoint, similar to send_call_function_single_ipi().
>>
>> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
>> ---
>>  kernel/smp.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index e2ca1e2f31274..c4d561cf50d45 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>>      smpcfd_prepare_cpu(smp_processor_id());
>>  }
>>
>> +static inline void
>
> Given the use of _RET_IP_, I would strongly recommend you use
> __always_inline.
>

Noted, thanks

>> +send_call_function_ipi_mask(const struct cpumask *mask)
>> +{
>> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>
> What's func?
>

A rebase fail... That's only plugged in later.

>> +	arch_send_call_function_ipi_mask(mask);
>> +}


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17 14:23       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:23 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On 17/11/22 10:08, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
>> This simply wraps around the arch function and prepends it with a
>> tracepoint, similar to send_call_function_single_ipi().
>>
>> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
>> ---
>>  kernel/smp.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index e2ca1e2f31274..c4d561cf50d45 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>>      smpcfd_prepare_cpu(smp_processor_id());
>>  }
>>
>> +static inline void
>
> Given the use of _RET_IP_, I would strongly recommend you use
> __always_inline.
>

Noted, thanks

>> +send_call_function_ipi_mask(const struct cpumask *mask)
>> +{
>> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>
> What's func?
>

A rebase fail... That's only plugged in later.

>> +	arch_send_call_function_ipi_mask(mask);
>> +}


^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17 14:23       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:23 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On 17/11/22 10:08, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
>> This simply wraps around the arch function and prepends it with a
>> tracepoint, similar to send_call_function_single_ipi().
>>
>> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
>> ---
>>  kernel/smp.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index e2ca1e2f31274..c4d561cf50d45 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>>      smpcfd_prepare_cpu(smp_processor_id());
>>  }
>>
>> +static inline void
>
> Given the use of _RET_IP_, I would strongly recommend you use
> __always_inline.
>

Noted, thanks

>> +send_call_function_ipi_mask(const struct cpumask *mask)
>> +{
>> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>
> What's func?
>

A rebase fail... That's only plugged in later.

>> +	arch_send_call_function_ipi_mask(mask);
>> +}


^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17 14:23       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:23 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On 17/11/22 10:08, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
>> This simply wraps around the arch function and prepends it with a
>> tracepoint, similar to send_call_function_single_ipi().
>>
>> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
>> ---
>>  kernel/smp.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index e2ca1e2f31274..c4d561cf50d45 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>>      smpcfd_prepare_cpu(smp_processor_id());
>>  }
>>
>> +static inline void
>
> Given the use of _RET_IP_, I would strongly recommend you use
> __always_inline.
>

Noted, thanks

>> +send_call_function_ipi_mask(const struct cpumask *mask)
>> +{
>> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>
> What's func?
>

A rebase fail... That's only plugged in later.

>> +	arch_send_call_function_ipi_mask(mask);
>> +}


^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17 14:23       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:23 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On 17/11/22 10:08, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
>> This simply wraps around the arch function and prepends it with a
>> tracepoint, similar to send_call_function_single_ipi().
>>
>> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
>> ---
>>  kernel/smp.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index e2ca1e2f31274..c4d561cf50d45 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>>      smpcfd_prepare_cpu(smp_processor_id());
>>  }
>>
>> +static inline void
>
> Given the use of _RET_IP_, I would strongly recommend you use
> __always_inline.
>

Noted, thanks

>> +send_call_function_ipi_mask(const struct cpumask *mask)
>> +{
>> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>
> What's func?
>

A rebase fail... That's only plugged in later.

>> +	arch_send_call_function_ipi_mask(mask);
>> +}


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
@ 2022-11-17 14:23       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:23 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar

On 17/11/22 10:08, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:32PM +0000, Valentin Schneider wrote:
>> This simply wraps around the arch function and prepends it with a
>> tracepoint, similar to send_call_function_single_ipi().
>>
>> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
>> ---
>>  kernel/smp.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index e2ca1e2f31274..c4d561cf50d45 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -160,6 +160,13 @@ void __init call_function_init(void)
>>      smpcfd_prepare_cpu(smp_processor_id());
>>  }
>>
>> +static inline void
>
> Given the use of _RET_IP_, I would strongly recommend you use
> __always_inline.
>

Noted, thanks

>> +send_call_function_ipi_mask(const struct cpumask *mask)
>> +{
>> +	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>
> What's func?
>

A rebase fail... That's only plugged in later.

>> +	arch_send_call_function_ipi_mask(mask);
>> +}

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
  2022-11-17  9:12     ` Peter Zijlstra
                         ` (3 preceding siblings ...)
  (?)
@ 2022-11-17 14:24       ` Valentin Schneider
  -1 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:24 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On 17/11/22 10:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:
>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index c4d561cf50d45..44fa4b9b1f46b 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>>      arch_send_call_function_ipi_mask(mask);
>>  }
>>
>> +void smp_send_reschedule(int cpu)
>> +{
>> +	/* XXX scheduler_ipi is inline :/ */
>> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>> +	arch_smp_send_reschedule(cpu);
>> +}
>> +EXPORT_SYMBOL_GPL(smp_send_reschedule);
>
> Yeah, no.. I see some crazy archs do this, but no we're not exporting
> this in generic.

So the list is: ia64, powerpc, riscv
and they all seem to do it because of KVM:
  c4cb768f0277 ("[IA64] export smp_send_reschedule")
  de56a948b918 ("KVM: PPC: Add support for Book3S processors in hypervisor mode")
  d3d7a0ce020e ("RISC-V: Export kernel symbols for kvm")

Other archs get out of it either because their smp_send_reschedule() is
inline (e.g. x86), or because they don't allow building KVM as a module
(e.g. arm64).

If I can cobble the tracepoint+reschedule in an inline helper, then that
wouldn't require any new exports - I'm fighting a bit with the header maze
ATM, but hopefully I can get somewhere with this.

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17 14:24       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:24 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Guo Ren,
	Paul E. McKenney, Steven Rostedt, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

On 17/11/22 10:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:
>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index c4d561cf50d45..44fa4b9b1f46b 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>>      arch_send_call_function_ipi_mask(mask);
>>  }
>>
>> +void smp_send_reschedule(int cpu)
>> +{
>> +	/* XXX scheduler_ipi is inline :/ */
>> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>> +	arch_smp_send_reschedule(cpu);
>> +}
>> +EXPORT_SYMBOL_GPL(smp_send_reschedule);
>
> Yeah, no.. I see some crazy archs do this, but no we're not exporting
> this in generic.

So the list is: ia64, powerpc, riscv
and they all seem to do it because of KVM:
  c4cb768f0277 ("[IA64] export smp_send_reschedule")
  de56a948b918 ("KVM: PPC: Add support for Book3S processors in hypervisor mode")
  d3d7a0ce020e ("RISC-V: Export kernel symbols for kvm")

Other archs get out of it either because their smp_send_reschedule() is
inline (e.g. x86), or because they don't allow building KVM as a module
(e.g. arm64).

If I can cobble the tracepoint+reschedule in an inline helper, then that
wouldn't require any new exports - I'm fighting a bit with the header maze
ATM, but hopefully I can get somewhere with this.


^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17 14:24       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:24 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Guo Ren,
	Paul E. McKenney, Steven Rostedt, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

On 17/11/22 10:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:
>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index c4d561cf50d45..44fa4b9b1f46b 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>>      arch_send_call_function_ipi_mask(mask);
>>  }
>>
>> +void smp_send_reschedule(int cpu)
>> +{
>> +	/* XXX scheduler_ipi is inline :/ */
>> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>> +	arch_smp_send_reschedule(cpu);
>> +}
>> +EXPORT_SYMBOL_GPL(smp_send_reschedule);
>
> Yeah, no.. I see some crazy archs do this, but no we're not exporting
> this in generic.

So the list is: ia64, powerpc, riscv
and they all seem to do it because of KVM:
  c4cb768f0277 ("[IA64] export smp_send_reschedule")
  de56a948b918 ("KVM: PPC: Add support for Book3S processors in hypervisor mode")
  d3d7a0ce020e ("RISC-V: Export kernel symbols for kvm")

Other archs get out of it either because their smp_send_reschedule() is
inline (e.g. x86), or because they don't allow building KVM as a module
(e.g. arm64).

If I can cobble the tracepoint+reschedule in an inline helper, then that
wouldn't require any new exports - I'm fighting a bit with the header maze
ATM, but hopefully I can get somewhere with this.


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17 14:24       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:24 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Guo Ren,
	Paul E. McKenney, Steven Rostedt, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

On 17/11/22 10:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:
>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index c4d561cf50d45..44fa4b9b1f46b 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>>      arch_send_call_function_ipi_mask(mask);
>>  }
>>
>> +void smp_send_reschedule(int cpu)
>> +{
>> +	/* XXX scheduler_ipi is inline :/ */
>> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>> +	arch_smp_send_reschedule(cpu);
>> +}
>> +EXPORT_SYMBOL_GPL(smp_send_reschedule);
>
> Yeah, no.. I see some crazy archs do this, but no we're not exporting
> this in generic.

So the list is: ia64, powerpc, riscv
and they all seem to do it because of KVM:
  c4cb768f0277 ("[IA64] export smp_send_reschedule")
  de56a948b918 ("KVM: PPC: Add support for Book3S processors in hypervisor mode")
  d3d7a0ce020e ("RISC-V: Export kernel symbols for kvm")

Other archs get out of it either because their smp_send_reschedule() is
inline (e.g. x86), or because they don't allow building KVM as a module
(e.g. arm64).

If I can cobble the tracepoint+reschedule in an inline helper, then that
wouldn't require any new exports - I'm fighting a bit with the header maze
ATM, but hopefully I can get somewhere with this.


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17 14:24       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:24 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Guo Ren,
	Paul E. McKenney, Steven Rostedt, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker,
	Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
	Marc Zyngier, Mark Rutland, Russell King, Nicholas Piggin,
	David S. Miller

On 17/11/22 10:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:
>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index c4d561cf50d45..44fa4b9b1f46b 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>>      arch_send_call_function_ipi_mask(mask);
>>  }
>>
>> +void smp_send_reschedule(int cpu)
>> +{
>> +	/* XXX scheduler_ipi is inline :/ */
>> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>> +	arch_smp_send_reschedule(cpu);
>> +}
>> +EXPORT_SYMBOL_GPL(smp_send_reschedule);
>
> Yeah, no.. I see some crazy archs do this, but no we're not exporting
> this in generic.

So the list is: ia64, powerpc, riscv
and they all seem to do it because of KVM:
  c4cb768f0277 ("[IA64] export smp_send_reschedule")
  de56a948b918 ("KVM: PPC: Add support for Book3S processors in hypervisor mode")
  d3d7a0ce020e ("RISC-V: Export kernel symbols for kvm")

Other archs get out of it either because their smp_send_reschedule() is
inline (e.g. x86), or because they don't allow building KVM as a module
(e.g. arm64).

If I can cobble the tracepoint+reschedule in an inline helper, then that
wouldn't require any new exports - I'm fighting a bit with the header maze
ATM, but hopefully I can get somewhere with this.


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule()
@ 2022-11-17 14:24       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:24 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Guo Ren,
	Paul E. McKenney, Steven Rostedt, Thomas Gleixner,
	Sebastian Andrzej Siewior, Juri Lelli,
	Daniel Bristot de Oliveira, Marcelo Tosatti, Frederic Weisbecker

On 17/11/22 10:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:
>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index c4d561cf50d45..44fa4b9b1f46b 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>>      arch_send_call_function_ipi_mask(mask);
>>  }
>>
>> +void smp_send_reschedule(int cpu)
>> +{
>> +	/* XXX scheduler_ipi is inline :/ */
>> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>> +	arch_smp_send_reschedule(cpu);
>> +}
>> +EXPORT_SYMBOL_GPL(smp_send_reschedule);
>
> Yeah, no.. I see some crazy archs do this, but no we're not exporting
> this in generic.

So the list is: ia64, powerpc, riscv
and they all seem to do it because of KVM:
  c4cb768f0277 ("[IA64] export smp_send_reschedule")
  de56a948b918 ("KVM: PPC: Add support for Book3S processors in hypervisor mode")
  d3d7a0ce020e ("RISC-V: Export kernel symbols for kvm")

Other archs get out of it either because their smp_send_reschedule() is
inline (e.g. x86), or because they don't allow building KVM as a module
(e.g. arm64).

If I can cobble the tracepoint+reschedule in an inline helper, then that
wouldn't require any new exports - I'm fighting a bit with the header maze
ATM, but hopefully I can get somewhere with this.

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
  2022-11-17 14:12     ` Peter Zijlstra
                         ` (5 preceding siblings ...)
  (?)
@ 2022-11-17 14:45       ` Valentin Schneider
  -1 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:45 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On 17/11/22 15:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> *yuck*

:-)

>
> How about something like so?
>
> ---
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>
>  #include <trace/events/ipi.h>
>
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
>       rq_unlock_irqrestore(rq, &rf);
>  }
>
> -void send_call_function_single_ipi(int cpu)
> +bool send_call_function_single_ipi(int cpu)
>  {
>       struct rq *rq = cpu_rq(cpu);
>
>       if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>               arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> +		return true;
>       }
> +
> +	trace_sched_wake_idle_without_ipi(cpu);
> +	return false;
>  }
>
>  /*
> --- a/kernel/sched/smp.h
> +++ b/kernel/sched/smp.h
> @@ -6,7 +6,7 @@
>
>  extern void sched_ttwu_pending(void *arg);
>
> -extern void send_call_function_single_ipi(int cpu);
> +extern bool send_call_function_single_ipi(int cpu);
>
>  #ifdef CONFIG_SMP
>  extern void flush_smp_call_function_queue(void);
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -163,7 +163,6 @@ void __init call_function_init(void)
>  static inline void
>  send_call_function_ipi_mask(const struct cpumask *mask)
>  {
> -	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>       arch_send_call_function_ipi_mask(mask);
>  }
>
> @@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
>       struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
>       struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
>       struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
> +	struct __call_single_data *csd;
> +
> +	csd = container_of(node, call_single_data_t, node.llist);
> +	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
>
>       cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
>       if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
>               cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
>               cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
> +		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
>               send_call_function_single_ipi(cpu);
>               cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
>       } else {
> @@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
>
>  static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
>
> +static __always_inline
> +bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
> +{
> +	/*
> +	 * The list addition should be visible to the target CPU when it pops
> +	 * the head of the list to pull the entry off it in the IPI handler
> +	 * because of normal cache coherency rules implied by the underlying
> +	 * llist ops.
> +	 *
> +	 * If IPIs can go out of order to the cache coherency protocol
> +	 * in an architecture, sufficient synchronisation should be added
> +	 * to arch code to make it appear to obey cache coherency WRT
> +	 * locking and barrier primitives. Generic code isn't really
> +	 * equipped to do the right thing...
> +	 */
> +	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> +		return send_call_function_single_ipi(cpu);
> +
> +	return false;
> +}
> +
>  void __smp_call_single_queue(int cpu, struct llist_node *node)
>  {
>  #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
> @@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
>  #endif
>
>       /*
> -	 * The list addition should be visible to the target CPU when it pops
> -	 * the head of the list to pull the entry off it in the IPI handler
> -	 * because of normal cache coherency rules implied by the underlying
> -	 * llist ops.
> -	 *
> -	 * If IPIs can go out of order to the cache coherency protocol
> -	 * in an architecture, sufficient synchronisation should be added
> -	 * to arch code to make it appear to obey cache coherency WRT
> -	 * locking and barrier primitives. Generic code isn't really
> -	 * equipped to do the right thing...
> -	 */
> -	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> -		send_call_function_single_ipi(cpu);
> +	 * We have to check the type of the CSD before queueing it, because
> +	 * once queued it can have its flags cleared by
> +	 *   flush_smp_call_function_queue()
> +	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
> +	 * executes migration_cpu_stop() on the remote CPU).
> +	 */
> +	if (trace_ipi_send_cpumask_enabled()) {
> +		call_single_data_t *csd;
> +		smp_call_func_t func;
> +
> +		csd = container_of(node, call_single_data_t, node.llist);
> +
> +		func = sched_ttwu_pending;
> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> +			func = csd->func;
> +
> +		if (raw_smp_call_single_queue(cpu, node))
> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);

So I went with the tracepoint being placed *before* the actual IPI gets
sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
e.g. trace_call_function_single_entry().

Packaging the call_single_queue logic makes the code less horrible, but it
does mix up the event ordering...


> +		return;
> +	}
> +
> +	raw_smp_call_single_queue(cpu, node);
>  }
>
>  /*
> @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
>                * number of CPUs might be zero due to concurrent changes to the
>                * provided mask.
>                */
> -		if (nr_cpus == 1)
> +		if (nr_cpus == 1) {
> +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
>                       send_call_function_single_ipi(last_cpu);

This'll yield an IPI event even if no IPI is sent due to the idle task
polling, no?

> -		else if (likely(nr_cpus > 1))
> -			send_call_function_ipi_mask(cfd->cpumask_ipi);
> +		} else if (likely(nr_cpus > 1)) {
> +			trace_ipi_send_cpumask(mask, _RET_IP_, func);
> +			send_call_function_ipi_mask(mask);
> +		}
>
>               cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
>       }


^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:45       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:45 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On 17/11/22 15:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> *yuck*

:-)

>
> How about something like so?
>
> ---
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>
>  #include <trace/events/ipi.h>
>
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
>       rq_unlock_irqrestore(rq, &rf);
>  }
>
> -void send_call_function_single_ipi(int cpu)
> +bool send_call_function_single_ipi(int cpu)
>  {
>       struct rq *rq = cpu_rq(cpu);
>
>       if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>               arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> +		return true;
>       }
> +
> +	trace_sched_wake_idle_without_ipi(cpu);
> +	return false;
>  }
>
>  /*
> --- a/kernel/sched/smp.h
> +++ b/kernel/sched/smp.h
> @@ -6,7 +6,7 @@
>
>  extern void sched_ttwu_pending(void *arg);
>
> -extern void send_call_function_single_ipi(int cpu);
> +extern bool send_call_function_single_ipi(int cpu);
>
>  #ifdef CONFIG_SMP
>  extern void flush_smp_call_function_queue(void);
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -163,7 +163,6 @@ void __init call_function_init(void)
>  static inline void
>  send_call_function_ipi_mask(const struct cpumask *mask)
>  {
> -	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>       arch_send_call_function_ipi_mask(mask);
>  }
>
> @@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
>       struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
>       struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
>       struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
> +	struct __call_single_data *csd;
> +
> +	csd = container_of(node, call_single_data_t, node.llist);
> +	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
>
>       cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
>       if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
>               cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
>               cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
> +		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
>               send_call_function_single_ipi(cpu);
>               cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
>       } else {
> @@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
>
>  static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
>
> +static __always_inline
> +bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
> +{
> +	/*
> +	 * The list addition should be visible to the target CPU when it pops
> +	 * the head of the list to pull the entry off it in the IPI handler
> +	 * because of normal cache coherency rules implied by the underlying
> +	 * llist ops.
> +	 *
> +	 * If IPIs can go out of order to the cache coherency protocol
> +	 * in an architecture, sufficient synchronisation should be added
> +	 * to arch code to make it appear to obey cache coherency WRT
> +	 * locking and barrier primitives. Generic code isn't really
> +	 * equipped to do the right thing...
> +	 */
> +	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> +		return send_call_function_single_ipi(cpu);
> +
> +	return false;
> +}
> +
>  void __smp_call_single_queue(int cpu, struct llist_node *node)
>  {
>  #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
> @@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
>  #endif
>
>       /*
> -	 * The list addition should be visible to the target CPU when it pops
> -	 * the head of the list to pull the entry off it in the IPI handler
> -	 * because of normal cache coherency rules implied by the underlying
> -	 * llist ops.
> -	 *
> -	 * If IPIs can go out of order to the cache coherency protocol
> -	 * in an architecture, sufficient synchronisation should be added
> -	 * to arch code to make it appear to obey cache coherency WRT
> -	 * locking and barrier primitives. Generic code isn't really
> -	 * equipped to do the right thing...
> -	 */
> -	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> -		send_call_function_single_ipi(cpu);
> +	 * We have to check the type of the CSD before queueing it, because
> +	 * once queued it can have its flags cleared by
> +	 *   flush_smp_call_function_queue()
> +	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
> +	 * executes migration_cpu_stop() on the remote CPU).
> +	 */
> +	if (trace_ipi_send_cpumask_enabled()) {
> +		call_single_data_t *csd;
> +		smp_call_func_t func;
> +
> +		csd = container_of(node, call_single_data_t, node.llist);
> +
> +		func = sched_ttwu_pending;
> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> +			func = csd->func;
> +
> +		if (raw_smp_call_single_queue(cpu, node))
> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);

So I went with the tracepoint being placed *before* the actual IPI gets
sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
e.g. trace_call_function_single_entry().

Packaging the call_single_queue logic makes the code less horrible, but it
does mix up the event ordering...


> +		return;
> +	}
> +
> +	raw_smp_call_single_queue(cpu, node);
>  }
>
>  /*
> @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
>                * number of CPUs might be zero due to concurrent changes to the
>                * provided mask.
>                */
> -		if (nr_cpus == 1)
> +		if (nr_cpus == 1) {
> +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
>                       send_call_function_single_ipi(last_cpu);

This'll yield an IPI event even if no IPI is sent due to the idle task
polling, no?

> -		else if (likely(nr_cpus > 1))
> -			send_call_function_ipi_mask(cfd->cpumask_ipi);
> +		} else if (likely(nr_cpus > 1)) {
> +			trace_ipi_send_cpumask(mask, _RET_IP_, func);
> +			send_call_function_ipi_mask(mask);
> +		}
>
>               cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
>       }


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:45       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:45 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On 17/11/22 15:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> *yuck*

:-)

>
> How about something like so?
>
> ---
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>
>  #include <trace/events/ipi.h>
>
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
>       rq_unlock_irqrestore(rq, &rf);
>  }
>
> -void send_call_function_single_ipi(int cpu)
> +bool send_call_function_single_ipi(int cpu)
>  {
>       struct rq *rq = cpu_rq(cpu);
>
>       if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>               arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> +		return true;
>       }
> +
> +	trace_sched_wake_idle_without_ipi(cpu);
> +	return false;
>  }
>
>  /*
> --- a/kernel/sched/smp.h
> +++ b/kernel/sched/smp.h
> @@ -6,7 +6,7 @@
>
>  extern void sched_ttwu_pending(void *arg);
>
> -extern void send_call_function_single_ipi(int cpu);
> +extern bool send_call_function_single_ipi(int cpu);
>
>  #ifdef CONFIG_SMP
>  extern void flush_smp_call_function_queue(void);
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -163,7 +163,6 @@ void __init call_function_init(void)
>  static inline void
>  send_call_function_ipi_mask(const struct cpumask *mask)
>  {
> -	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>       arch_send_call_function_ipi_mask(mask);
>  }
>
> @@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
>       struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
>       struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
>       struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
> +	struct __call_single_data *csd;
> +
> +	csd = container_of(node, call_single_data_t, node.llist);
> +	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
>
>       cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
>       if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
>               cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
>               cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
> +		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
>               send_call_function_single_ipi(cpu);
>               cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
>       } else {
> @@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
>
>  static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
>
> +static __always_inline
> +bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
> +{
> +	/*
> +	 * The list addition should be visible to the target CPU when it pops
> +	 * the head of the list to pull the entry off it in the IPI handler
> +	 * because of normal cache coherency rules implied by the underlying
> +	 * llist ops.
> +	 *
> +	 * If IPIs can go out of order to the cache coherency protocol
> +	 * in an architecture, sufficient synchronisation should be added
> +	 * to arch code to make it appear to obey cache coherency WRT
> +	 * locking and barrier primitives. Generic code isn't really
> +	 * equipped to do the right thing...
> +	 */
> +	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> +		return send_call_function_single_ipi(cpu);
> +
> +	return false;
> +}
> +
>  void __smp_call_single_queue(int cpu, struct llist_node *node)
>  {
>  #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
> @@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
>  #endif
>
>       /*
> -	 * The list addition should be visible to the target CPU when it pops
> -	 * the head of the list to pull the entry off it in the IPI handler
> -	 * because of normal cache coherency rules implied by the underlying
> -	 * llist ops.
> -	 *
> -	 * If IPIs can go out of order to the cache coherency protocol
> -	 * in an architecture, sufficient synchronisation should be added
> -	 * to arch code to make it appear to obey cache coherency WRT
> -	 * locking and barrier primitives. Generic code isn't really
> -	 * equipped to do the right thing...
> -	 */
> -	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> -		send_call_function_single_ipi(cpu);
> +	 * We have to check the type of the CSD before queueing it, because
> +	 * once queued it can have its flags cleared by
> +	 *   flush_smp_call_function_queue()
> +	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
> +	 * executes migration_cpu_stop() on the remote CPU).
> +	 */
> +	if (trace_ipi_send_cpumask_enabled()) {
> +		call_single_data_t *csd;
> +		smp_call_func_t func;
> +
> +		csd = container_of(node, call_single_data_t, node.llist);
> +
> +		func = sched_ttwu_pending;
> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> +			func = csd->func;
> +
> +		if (raw_smp_call_single_queue(cpu, node))
> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);

So I went with the tracepoint being placed *before* the actual IPI gets
sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
e.g. trace_call_function_single_entry().

Packaging the call_single_queue logic makes the code less horrible, but it
does mix up the event ordering...


> +		return;
> +	}
> +
> +	raw_smp_call_single_queue(cpu, node);
>  }
>
>  /*
> @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
>                * number of CPUs might be zero due to concurrent changes to the
>                * provided mask.
>                */
> -		if (nr_cpus == 1)
> +		if (nr_cpus == 1) {
> +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
>                       send_call_function_single_ipi(last_cpu);

This'll yield an IPI event even if no IPI is sent due to the idle task
polling, no?

> -		else if (likely(nr_cpus > 1))
> -			send_call_function_ipi_mask(cfd->cpumask_ipi);
> +		} else if (likely(nr_cpus > 1)) {
> +			trace_ipi_send_cpumask(mask, _RET_IP_, func);
> +			send_call_function_ipi_mask(mask);
> +		}
>
>               cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
>       }


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:45       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:45 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On 17/11/22 15:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> *yuck*

:-)

>
> How about something like so?
>
> ---
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>
>  #include <trace/events/ipi.h>
>
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
>       rq_unlock_irqrestore(rq, &rf);
>  }
>
> -void send_call_function_single_ipi(int cpu)
> +bool send_call_function_single_ipi(int cpu)
>  {
>       struct rq *rq = cpu_rq(cpu);
>
>       if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>               arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> +		return true;
>       }
> +
> +	trace_sched_wake_idle_without_ipi(cpu);
> +	return false;
>  }
>
>  /*
> --- a/kernel/sched/smp.h
> +++ b/kernel/sched/smp.h
> @@ -6,7 +6,7 @@
>
>  extern void sched_ttwu_pending(void *arg);
>
> -extern void send_call_function_single_ipi(int cpu);
> +extern bool send_call_function_single_ipi(int cpu);
>
>  #ifdef CONFIG_SMP
>  extern void flush_smp_call_function_queue(void);
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -163,7 +163,6 @@ void __init call_function_init(void)
>  static inline void
>  send_call_function_ipi_mask(const struct cpumask *mask)
>  {
> -	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>       arch_send_call_function_ipi_mask(mask);
>  }
>
> @@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
>       struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
>       struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
>       struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
> +	struct __call_single_data *csd;
> +
> +	csd = container_of(node, call_single_data_t, node.llist);
> +	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
>
>       cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
>       if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
>               cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
>               cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
> +		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
>               send_call_function_single_ipi(cpu);
>               cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
>       } else {
> @@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
>
>  static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
>
> +static __always_inline
> +bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
> +{
> +	/*
> +	 * The list addition should be visible to the target CPU when it pops
> +	 * the head of the list to pull the entry off it in the IPI handler
> +	 * because of normal cache coherency rules implied by the underlying
> +	 * llist ops.
> +	 *
> +	 * If IPIs can go out of order to the cache coherency protocol
> +	 * in an architecture, sufficient synchronisation should be added
> +	 * to arch code to make it appear to obey cache coherency WRT
> +	 * locking and barrier primitives. Generic code isn't really
> +	 * equipped to do the right thing...
> +	 */
> +	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> +		return send_call_function_single_ipi(cpu);
> +
> +	return false;
> +}
> +
>  void __smp_call_single_queue(int cpu, struct llist_node *node)
>  {
>  #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
> @@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
>  #endif
>
>       /*
> -	 * The list addition should be visible to the target CPU when it pops
> -	 * the head of the list to pull the entry off it in the IPI handler
> -	 * because of normal cache coherency rules implied by the underlying
> -	 * llist ops.
> -	 *
> -	 * If IPIs can go out of order to the cache coherency protocol
> -	 * in an architecture, sufficient synchronisation should be added
> -	 * to arch code to make it appear to obey cache coherency WRT
> -	 * locking and barrier primitives. Generic code isn't really
> -	 * equipped to do the right thing...
> -	 */
> -	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> -		send_call_function_single_ipi(cpu);
> +	 * We have to check the type of the CSD before queueing it, because
> +	 * once queued it can have its flags cleared by
> +	 *   flush_smp_call_function_queue()
> +	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
> +	 * executes migration_cpu_stop() on the remote CPU).
> +	 */
> +	if (trace_ipi_send_cpumask_enabled()) {
> +		call_single_data_t *csd;
> +		smp_call_func_t func;
> +
> +		csd = container_of(node, call_single_data_t, node.llist);
> +
> +		func = sched_ttwu_pending;
> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> +			func = csd->func;
> +
> +		if (raw_smp_call_single_queue(cpu, node))
> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);

So I went with the tracepoint being placed *before* the actual IPI gets
sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
e.g. trace_call_function_single_entry().

Packaging the call_single_queue logic makes the code less horrible, but it
does mix up the event ordering...


> +		return;
> +	}
> +
> +	raw_smp_call_single_queue(cpu, node);
>  }
>
>  /*
> @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
>                * number of CPUs might be zero due to concurrent changes to the
>                * provided mask.
>                */
> -		if (nr_cpus == 1)
> +		if (nr_cpus == 1) {
> +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
>                       send_call_function_single_ipi(last_cpu);

This'll yield an IPI event even if no IPI is sent due to the idle task
polling, no?

> -		else if (likely(nr_cpus > 1))
> -			send_call_function_ipi_mask(cfd->cpumask_ipi);
> +		} else if (likely(nr_cpus > 1)) {
> +			trace_ipi_send_cpumask(mask, _RET_IP_, func);
> +			send_call_function_ipi_mask(mask);
> +		}
>
>               cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
>       }


^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:45       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:45 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On 17/11/22 15:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> *yuck*

:-)

>
> How about something like so?
>
> ---
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>
>  #include <trace/events/ipi.h>
>
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
>       rq_unlock_irqrestore(rq, &rf);
>  }
>
> -void send_call_function_single_ipi(int cpu)
> +bool send_call_function_single_ipi(int cpu)
>  {
>       struct rq *rq = cpu_rq(cpu);
>
>       if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>               arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> +		return true;
>       }
> +
> +	trace_sched_wake_idle_without_ipi(cpu);
> +	return false;
>  }
>
>  /*
> --- a/kernel/sched/smp.h
> +++ b/kernel/sched/smp.h
> @@ -6,7 +6,7 @@
>
>  extern void sched_ttwu_pending(void *arg);
>
> -extern void send_call_function_single_ipi(int cpu);
> +extern bool send_call_function_single_ipi(int cpu);
>
>  #ifdef CONFIG_SMP
>  extern void flush_smp_call_function_queue(void);
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -163,7 +163,6 @@ void __init call_function_init(void)
>  static inline void
>  send_call_function_ipi_mask(const struct cpumask *mask)
>  {
> -	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>       arch_send_call_function_ipi_mask(mask);
>  }
>
> @@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
>       struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
>       struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
>       struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
> +	struct __call_single_data *csd;
> +
> +	csd = container_of(node, call_single_data_t, node.llist);
> +	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
>
>       cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
>       if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
>               cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
>               cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
> +		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
>               send_call_function_single_ipi(cpu);
>               cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
>       } else {
> @@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
>
>  static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
>
> +static __always_inline
> +bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
> +{
> +	/*
> +	 * The list addition should be visible to the target CPU when it pops
> +	 * the head of the list to pull the entry off it in the IPI handler
> +	 * because of normal cache coherency rules implied by the underlying
> +	 * llist ops.
> +	 *
> +	 * If IPIs can go out of order to the cache coherency protocol
> +	 * in an architecture, sufficient synchronisation should be added
> +	 * to arch code to make it appear to obey cache coherency WRT
> +	 * locking and barrier primitives. Generic code isn't really
> +	 * equipped to do the right thing...
> +	 */
> +	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> +		return send_call_function_single_ipi(cpu);
> +
> +	return false;
> +}
> +
>  void __smp_call_single_queue(int cpu, struct llist_node *node)
>  {
>  #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
> @@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
>  #endif
>
>       /*
> -	 * The list addition should be visible to the target CPU when it pops
> -	 * the head of the list to pull the entry off it in the IPI handler
> -	 * because of normal cache coherency rules implied by the underlying
> -	 * llist ops.
> -	 *
> -	 * If IPIs can go out of order to the cache coherency protocol
> -	 * in an architecture, sufficient synchronisation should be added
> -	 * to arch code to make it appear to obey cache coherency WRT
> -	 * locking and barrier primitives. Generic code isn't really
> -	 * equipped to do the right thing...
> -	 */
> -	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> -		send_call_function_single_ipi(cpu);
> +	 * We have to check the type of the CSD before queueing it, because
> +	 * once queued it can have its flags cleared by
> +	 *   flush_smp_call_function_queue()
> +	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
> +	 * executes migration_cpu_stop() on the remote CPU).
> +	 */
> +	if (trace_ipi_send_cpumask_enabled()) {
> +		call_single_data_t *csd;
> +		smp_call_func_t func;
> +
> +		csd = container_of(node, call_single_data_t, node.llist);
> +
> +		func = sched_ttwu_pending;
> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> +			func = csd->func;
> +
> +		if (raw_smp_call_single_queue(cpu, node))
> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);

So I went with the tracepoint being placed *before* the actual IPI gets
sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
e.g. trace_call_function_single_entry().

Packaging the call_single_queue logic makes the code less horrible, but it
does mix up the event ordering...


> +		return;
> +	}
> +
> +	raw_smp_call_single_queue(cpu, node);
>  }
>
>  /*
> @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
>                * number of CPUs might be zero due to concurrent changes to the
>                * provided mask.
>                */
> -		if (nr_cpus == 1)
> +		if (nr_cpus == 1) {
> +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
>                       send_call_function_single_ipi(last_cpu);

This'll yield an IPI event even if no IPI is sent due to the idle task
polling, no?

> -		else if (likely(nr_cpus > 1))
> -			send_call_function_ipi_mask(cfd->cpumask_ipi);
> +		} else if (likely(nr_cpus > 1)) {
> +			trace_ipi_send_cpumask(mask, _RET_IP_, func);
> +			send_call_function_ipi_mask(mask);
> +		}
>
>               cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
>       }


^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:45       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:45 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On 17/11/22 15:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> *yuck*

:-)

>
> How about something like so?
>
> ---
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>
>  #include <trace/events/ipi.h>
>
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
>       rq_unlock_irqrestore(rq, &rf);
>  }
>
> -void send_call_function_single_ipi(int cpu)
> +bool send_call_function_single_ipi(int cpu)
>  {
>       struct rq *rq = cpu_rq(cpu);
>
>       if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>               arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> +		return true;
>       }
> +
> +	trace_sched_wake_idle_without_ipi(cpu);
> +	return false;
>  }
>
>  /*
> --- a/kernel/sched/smp.h
> +++ b/kernel/sched/smp.h
> @@ -6,7 +6,7 @@
>
>  extern void sched_ttwu_pending(void *arg);
>
> -extern void send_call_function_single_ipi(int cpu);
> +extern bool send_call_function_single_ipi(int cpu);
>
>  #ifdef CONFIG_SMP
>  extern void flush_smp_call_function_queue(void);
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -163,7 +163,6 @@ void __init call_function_init(void)
>  static inline void
>  send_call_function_ipi_mask(const struct cpumask *mask)
>  {
> -	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>       arch_send_call_function_ipi_mask(mask);
>  }
>
> @@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
>       struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
>       struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
>       struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
> +	struct __call_single_data *csd;
> +
> +	csd = container_of(node, call_single_data_t, node.llist);
> +	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
>
>       cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
>       if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
>               cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
>               cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
> +		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
>               send_call_function_single_ipi(cpu);
>               cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
>       } else {
> @@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
>
>  static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
>
> +static __always_inline
> +bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
> +{
> +	/*
> +	 * The list addition should be visible to the target CPU when it pops
> +	 * the head of the list to pull the entry off it in the IPI handler
> +	 * because of normal cache coherency rules implied by the underlying
> +	 * llist ops.
> +	 *
> +	 * If IPIs can go out of order to the cache coherency protocol
> +	 * in an architecture, sufficient synchronisation should be added
> +	 * to arch code to make it appear to obey cache coherency WRT
> +	 * locking and barrier primitives. Generic code isn't really
> +	 * equipped to do the right thing...
> +	 */
> +	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> +		return send_call_function_single_ipi(cpu);
> +
> +	return false;
> +}
> +
>  void __smp_call_single_queue(int cpu, struct llist_node *node)
>  {
>  #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
> @@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
>  #endif
>
>       /*
> -	 * The list addition should be visible to the target CPU when it pops
> -	 * the head of the list to pull the entry off it in the IPI handler
> -	 * because of normal cache coherency rules implied by the underlying
> -	 * llist ops.
> -	 *
> -	 * If IPIs can go out of order to the cache coherency protocol
> -	 * in an architecture, sufficient synchronisation should be added
> -	 * to arch code to make it appear to obey cache coherency WRT
> -	 * locking and barrier primitives. Generic code isn't really
> -	 * equipped to do the right thing...
> -	 */
> -	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> -		send_call_function_single_ipi(cpu);
> +	 * We have to check the type of the CSD before queueing it, because
> +	 * once queued it can have its flags cleared by
> +	 *   flush_smp_call_function_queue()
> +	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
> +	 * executes migration_cpu_stop() on the remote CPU).
> +	 */
> +	if (trace_ipi_send_cpumask_enabled()) {
> +		call_single_data_t *csd;
> +		smp_call_func_t func;
> +
> +		csd = container_of(node, call_single_data_t, node.llist);
> +
> +		func = sched_ttwu_pending;
> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> +			func = csd->func;
> +
> +		if (raw_smp_call_single_queue(cpu, node))
> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);

So I went with the tracepoint being placed *before* the actual IPI gets
sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
e.g. trace_call_function_single_entry().

Packaging the call_single_queue logic makes the code less horrible, but it
does mix up the event ordering...


> +		return;
> +	}
> +
> +	raw_smp_call_single_queue(cpu, node);
>  }
>
>  /*
> @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
>                * number of CPUs might be zero due to concurrent changes to the
>                * provided mask.
>                */
> -		if (nr_cpus == 1)
> +		if (nr_cpus == 1) {
> +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
>                       send_call_function_single_ipi(last_cpu);

This'll yield an IPI event even if no IPI is sent due to the idle task
polling, no?

> -		else if (likely(nr_cpus > 1))
> -			send_call_function_ipi_mask(cfd->cpumask_ipi);
> +		} else if (likely(nr_cpus > 1)) {
> +			trace_ipi_send_cpumask(mask, _RET_IP_, func);
> +			send_call_function_ipi_mask(mask);
> +		}
>
>               cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
>       }


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:45       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:45 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On 17/11/22 15:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> *yuck*

:-)

>
> How about something like so?
>
> ---
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>
>  #include <trace/events/ipi.h>
>
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
>       rq_unlock_irqrestore(rq, &rf);
>  }
>
> -void send_call_function_single_ipi(int cpu)
> +bool send_call_function_single_ipi(int cpu)
>  {
>       struct rq *rq = cpu_rq(cpu);
>
>       if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>               arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> +		return true;
>       }
> +
> +	trace_sched_wake_idle_without_ipi(cpu);
> +	return false;
>  }
>
>  /*
> --- a/kernel/sched/smp.h
> +++ b/kernel/sched/smp.h
> @@ -6,7 +6,7 @@
>
>  extern void sched_ttwu_pending(void *arg);
>
> -extern void send_call_function_single_ipi(int cpu);
> +extern bool send_call_function_single_ipi(int cpu);
>
>  #ifdef CONFIG_SMP
>  extern void flush_smp_call_function_queue(void);
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -163,7 +163,6 @@ void __init call_function_init(void)
>  static inline void
>  send_call_function_ipi_mask(const struct cpumask *mask)
>  {
> -	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>       arch_send_call_function_ipi_mask(mask);
>  }
>
> @@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
>       struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
>       struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
>       struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
> +	struct __call_single_data *csd;
> +
> +	csd = container_of(node, call_single_data_t, node.llist);
> +	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
>
>       cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
>       if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
>               cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
>               cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
> +		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
>               send_call_function_single_ipi(cpu);
>               cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
>       } else {
> @@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
>
>  static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
>
> +static __always_inline
> +bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
> +{
> +	/*
> +	 * The list addition should be visible to the target CPU when it pops
> +	 * the head of the list to pull the entry off it in the IPI handler
> +	 * because of normal cache coherency rules implied by the underlying
> +	 * llist ops.
> +	 *
> +	 * If IPIs can go out of order to the cache coherency protocol
> +	 * in an architecture, sufficient synchronisation should be added
> +	 * to arch code to make it appear to obey cache coherency WRT
> +	 * locking and barrier primitives. Generic code isn't really
> +	 * equipped to do the right thing...
> +	 */
> +	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> +		return send_call_function_single_ipi(cpu);
> +
> +	return false;
> +}
> +
>  void __smp_call_single_queue(int cpu, struct llist_node *node)
>  {
>  #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
> @@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
>  #endif
>
>       /*
> -	 * The list addition should be visible to the target CPU when it pops
> -	 * the head of the list to pull the entry off it in the IPI handler
> -	 * because of normal cache coherency rules implied by the underlying
> -	 * llist ops.
> -	 *
> -	 * If IPIs can go out of order to the cache coherency protocol
> -	 * in an architecture, sufficient synchronisation should be added
> -	 * to arch code to make it appear to obey cache coherency WRT
> -	 * locking and barrier primitives. Generic code isn't really
> -	 * equipped to do the right thing...
> -	 */
> -	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> -		send_call_function_single_ipi(cpu);
> +	 * We have to check the type of the CSD before queueing it, because
> +	 * once queued it can have its flags cleared by
> +	 *   flush_smp_call_function_queue()
> +	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
> +	 * executes migration_cpu_stop() on the remote CPU).
> +	 */
> +	if (trace_ipi_send_cpumask_enabled()) {
> +		call_single_data_t *csd;
> +		smp_call_func_t func;
> +
> +		csd = container_of(node, call_single_data_t, node.llist);
> +
> +		func = sched_ttwu_pending;
> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> +			func = csd->func;
> +
> +		if (raw_smp_call_single_queue(cpu, node))
> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);

So I went with the tracepoint being placed *before* the actual IPI gets
sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
e.g. trace_call_function_single_entry().

Packaging the call_single_queue logic makes the code less horrible, but it
does mix up the event ordering...


> +		return;
> +	}
> +
> +	raw_smp_call_single_queue(cpu, node);
>  }
>
>  /*
> @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
>                * number of CPUs might be zero due to concurrent changes to the
>                * provided mask.
>                */
> -		if (nr_cpus = 1)
> +		if (nr_cpus = 1) {
> +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
>                       send_call_function_single_ipi(last_cpu);

This'll yield an IPI event even if no IPI is sent due to the idle task
polling, no?

> -		else if (likely(nr_cpus > 1))
> -			send_call_function_ipi_mask(cfd->cpumask_ipi);
> +		} else if (likely(nr_cpus > 1)) {
> +			trace_ipi_send_cpumask(mask, _RET_IP_, func);
> +			send_call_function_ipi_mask(mask);
> +		}
>
>               cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
>       }

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-17 14:45       ` Valentin Schneider
  0 siblings, 0 replies; 131+ messages in thread
From: Valentin Schneider @ 2022-11-17 14:45 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar

On 17/11/22 15:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:36PM +0000, Valentin Schneider wrote:
> *yuck*

:-)

>
> How about something like so?
>
> ---
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
>
>  #include <trace/events/ipi.h>
>
> +#include "sched/smp.h"
> +
>  static DEFINE_PER_CPU(struct llist_head, raised_list);
>  static DEFINE_PER_CPU(struct llist_head, lazy_list);
>  static DEFINE_PER_CPU(struct task_struct *, irq_workd);
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3763,16 +3763,17 @@ void sched_ttwu_pending(void *arg)
>       rq_unlock_irqrestore(rq, &rf);
>  }
>
> -void send_call_function_single_ipi(int cpu)
> +bool send_call_function_single_ipi(int cpu)
>  {
>       struct rq *rq = cpu_rq(cpu);
>
>       if (!set_nr_if_polling(rq->idle)) {
> -		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>               arch_send_call_function_single_ipi(cpu);
> -	} else {
> -		trace_sched_wake_idle_without_ipi(cpu);
> +		return true;
>       }
> +
> +	trace_sched_wake_idle_without_ipi(cpu);
> +	return false;
>  }
>
>  /*
> --- a/kernel/sched/smp.h
> +++ b/kernel/sched/smp.h
> @@ -6,7 +6,7 @@
>
>  extern void sched_ttwu_pending(void *arg);
>
> -extern void send_call_function_single_ipi(int cpu);
> +extern bool send_call_function_single_ipi(int cpu);
>
>  #ifdef CONFIG_SMP
>  extern void flush_smp_call_function_queue(void);
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -163,7 +163,6 @@ void __init call_function_init(void)
>  static inline void
>  send_call_function_ipi_mask(const struct cpumask *mask)
>  {
> -	trace_ipi_send_cpumask(mask, _RET_IP_, func);
>       arch_send_call_function_ipi_mask(mask);
>  }
>
> @@ -438,11 +437,16 @@ static void __smp_call_single_queue_debu
>       struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
>       struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
>       struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
> +	struct __call_single_data *csd;
> +
> +	csd = container_of(node, call_single_data_t, node.llist);
> +	WARN_ON_ONCE(!(CSD_TYPE(csd) & (CSD_TYPE_SYNC | CSD_TYPE_ASYNC)));
>
>       cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
>       if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
>               cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
>               cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
> +		trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, csd->func);
>               send_call_function_single_ipi(cpu);
>               cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
>       } else {
> @@ -487,6 +491,27 @@ static __always_inline void csd_unlock(s
>
>  static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
>
> +static __always_inline
> +bool raw_smp_call_single_queue(int cpu, struct llist_node *node)
> +{
> +	/*
> +	 * The list addition should be visible to the target CPU when it pops
> +	 * the head of the list to pull the entry off it in the IPI handler
> +	 * because of normal cache coherency rules implied by the underlying
> +	 * llist ops.
> +	 *
> +	 * If IPIs can go out of order to the cache coherency protocol
> +	 * in an architecture, sufficient synchronisation should be added
> +	 * to arch code to make it appear to obey cache coherency WRT
> +	 * locking and barrier primitives. Generic code isn't really
> +	 * equipped to do the right thing...
> +	 */
> +	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> +		return send_call_function_single_ipi(cpu);
> +
> +	return false;
> +}
> +
>  void __smp_call_single_queue(int cpu, struct llist_node *node)
>  {
>  #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
> @@ -503,19 +528,28 @@ void __smp_call_single_queue(int cpu, st
>  #endif
>
>       /*
> -	 * The list addition should be visible to the target CPU when it pops
> -	 * the head of the list to pull the entry off it in the IPI handler
> -	 * because of normal cache coherency rules implied by the underlying
> -	 * llist ops.
> -	 *
> -	 * If IPIs can go out of order to the cache coherency protocol
> -	 * in an architecture, sufficient synchronisation should be added
> -	 * to arch code to make it appear to obey cache coherency WRT
> -	 * locking and barrier primitives. Generic code isn't really
> -	 * equipped to do the right thing...
> -	 */
> -	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
> -		send_call_function_single_ipi(cpu);
> +	 * We have to check the type of the CSD before queueing it, because
> +	 * once queued it can have its flags cleared by
> +	 *   flush_smp_call_function_queue()
> +	 * even if we haven't sent the smp_call IPI yet (e.g. the stopper
> +	 * executes migration_cpu_stop() on the remote CPU).
> +	 */
> +	if (trace_ipi_send_cpumask_enabled()) {
> +		call_single_data_t *csd;
> +		smp_call_func_t func;
> +
> +		csd = container_of(node, call_single_data_t, node.llist);
> +
> +		func = sched_ttwu_pending;
> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> +			func = csd->func;
> +
> +		if (raw_smp_call_single_queue(cpu, node))
> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);

So I went with the tracepoint being placed *before* the actual IPI gets
sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
e.g. trace_call_function_single_entry().

Packaging the call_single_queue logic makes the code less horrible, but it
does mix up the event ordering...


> +		return;
> +	}
> +
> +	raw_smp_call_single_queue(cpu, node);
>  }
>
>  /*
> @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
>                * number of CPUs might be zero due to concurrent changes to the
>                * provided mask.
>                */
> -		if (nr_cpus == 1)
> +		if (nr_cpus == 1) {
> +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
>                       send_call_function_single_ipi(last_cpu);

This'll yield an IPI event even if no IPI is sent due to the idle task
polling, no?

> -		else if (likely(nr_cpus > 1))
> -			send_call_function_ipi_mask(cfd->cpumask_ipi);
> +		} else if (likely(nr_cpus > 1)) {
> +			trace_ipi_send_cpumask(mask, _RET_IP_, func);
> +			send_call_function_ipi_mask(mask);
> +		}
>
>               cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
>       }

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
  2022-11-17 14:45       ` Valentin Schneider
                           ` (5 preceding siblings ...)
  (?)
@ 2022-11-18  9:12         ` Peter Zijlstra
  -1 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-18  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:

> > +	if (trace_ipi_send_cpumask_enabled()) {
> > +		call_single_data_t *csd;
> > +		smp_call_func_t func;
> > +
> > +		csd = container_of(node, call_single_data_t, node.llist);
> > +
> > +		func = sched_ttwu_pending;
> > +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> > +			func = csd->func;
> > +
> > +		if (raw_smp_call_single_queue(cpu, node))
> > +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
> 
> So I went with the tracepoint being placed *before* the actual IPI gets
> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
> e.g. trace_call_function_single_entry().
> 
> Packaging the call_single_queue logic makes the code less horrible, but it
> does mix up the event ordering...

Keeps em sharp ;-)

> > +		return;
> > +	}
> > +
> > +	raw_smp_call_single_queue(cpu, node);
> >  }
> >
> >  /*
> > @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
> >                * number of CPUs might be zero due to concurrent changes to the
> >                * provided mask.
> >                */
> > -		if (nr_cpus == 1)
> > +		if (nr_cpus == 1) {
> > +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
> >                       send_call_function_single_ipi(last_cpu);
> 
> This'll yield an IPI event even if no IPI is sent due to the idle task
> polling, no?

Oh, right..

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18  9:12         ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-18  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:

> > +	if (trace_ipi_send_cpumask_enabled()) {
> > +		call_single_data_t *csd;
> > +		smp_call_func_t func;
> > +
> > +		csd = container_of(node, call_single_data_t, node.llist);
> > +
> > +		func = sched_ttwu_pending;
> > +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> > +			func = csd->func;
> > +
> > +		if (raw_smp_call_single_queue(cpu, node))
> > +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
> 
> So I went with the tracepoint being placed *before* the actual IPI gets
> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
> e.g. trace_call_function_single_entry().
> 
> Packaging the call_single_queue logic makes the code less horrible, but it
> does mix up the event ordering...

Keeps em sharp ;-)

> > +		return;
> > +	}
> > +
> > +	raw_smp_call_single_queue(cpu, node);
> >  }
> >
> >  /*
> > @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
> >                * number of CPUs might be zero due to concurrent changes to the
> >                * provided mask.
> >                */
> > -		if (nr_cpus == 1)
> > +		if (nr_cpus == 1) {
> > +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
> >                       send_call_function_single_ipi(last_cpu);
> 
> This'll yield an IPI event even if no IPI is sent due to the idle task
> polling, no?

Oh, right..

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18  9:12         ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-18  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:

> > +	if (trace_ipi_send_cpumask_enabled()) {
> > +		call_single_data_t *csd;
> > +		smp_call_func_t func;
> > +
> > +		csd = container_of(node, call_single_data_t, node.llist);
> > +
> > +		func = sched_ttwu_pending;
> > +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> > +			func = csd->func;
> > +
> > +		if (raw_smp_call_single_queue(cpu, node))
> > +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
> 
> So I went with the tracepoint being placed *before* the actual IPI gets
> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
> e.g. trace_call_function_single_entry().
> 
> Packaging the call_single_queue logic makes the code less horrible, but it
> does mix up the event ordering...

Keeps em sharp ;-)

> > +		return;
> > +	}
> > +
> > +	raw_smp_call_single_queue(cpu, node);
> >  }
> >
> >  /*
> > @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
> >                * number of CPUs might be zero due to concurrent changes to the
> >                * provided mask.
> >                */
> > -		if (nr_cpus == 1)
> > +		if (nr_cpus == 1) {
> > +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
> >                       send_call_function_single_ipi(last_cpu);
> 
> This'll yield an IPI event even if no IPI is sent due to the idle task
> polling, no?

Oh, right..

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18  9:12         ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-18  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:

> > +	if (trace_ipi_send_cpumask_enabled()) {
> > +		call_single_data_t *csd;
> > +		smp_call_func_t func;
> > +
> > +		csd = container_of(node, call_single_data_t, node.llist);
> > +
> > +		func = sched_ttwu_pending;
> > +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> > +			func = csd->func;
> > +
> > +		if (raw_smp_call_single_queue(cpu, node))
> > +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
> 
> So I went with the tracepoint being placed *before* the actual IPI gets
> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
> e.g. trace_call_function_single_entry().
> 
> Packaging the call_single_queue logic makes the code less horrible, but it
> does mix up the event ordering...

Keeps em sharp ;-)

> > +		return;
> > +	}
> > +
> > +	raw_smp_call_single_queue(cpu, node);
> >  }
> >
> >  /*
> > @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
> >                * number of CPUs might be zero due to concurrent changes to the
> >                * provided mask.
> >                */
> > -		if (nr_cpus == 1)
> > +		if (nr_cpus == 1) {
> > +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
> >                       send_call_function_single_ipi(last_cpu);
> 
> This'll yield an IPI event even if no IPI is sent due to the idle task
> polling, no?

Oh, right..

_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18  9:12         ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-18  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar, Borislav Petkov, Dave Hansen,
	H. Peter Anvin, Marc Zyngier, Mark Rutland, Russell King,
	Nicholas Piggin, Guo Ren, David S. Miller

On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:

> > +	if (trace_ipi_send_cpumask_enabled()) {
> > +		call_single_data_t *csd;
> > +		smp_call_func_t func;
> > +
> > +		csd = container_of(node, call_single_data_t, node.llist);
> > +
> > +		func = sched_ttwu_pending;
> > +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> > +			func = csd->func;
> > +
> > +		if (raw_smp_call_single_queue(cpu, node))
> > +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
> 
> So I went with the tracepoint being placed *before* the actual IPI gets
> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
> e.g. trace_call_function_single_entry().
> 
> Packaging the call_single_queue logic makes the code less horrible, but it
> does mix up the event ordering...

Keeps em sharp ;-)

> > +		return;
> > +	}
> > +
> > +	raw_smp_call_single_queue(cpu, node);
> >  }
> >
> >  /*
> > @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
> >                * number of CPUs might be zero due to concurrent changes to the
> >                * provided mask.
> >                */
> > -		if (nr_cpus == 1)
> > +		if (nr_cpus == 1) {
> > +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
> >                       send_call_function_single_ipi(last_cpu);
> 
> This'll yield an IPI event even if no IPI is sent due to the idle task
> polling, no?

Oh, right..

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18  9:12         ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-18  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:

> > +	if (trace_ipi_send_cpumask_enabled()) {
> > +		call_single_data_t *csd;
> > +		smp_call_func_t func;
> > +
> > +		csd = container_of(node, call_single_data_t, node.llist);
> > +
> > +		func = sched_ttwu_pending;
> > +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> > +			func = csd->func;
> > +
> > +		if (raw_smp_call_single_queue(cpu, node))
> > +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
> 
> So I went with the tracepoint being placed *before* the actual IPI gets
> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
> e.g. trace_call_function_single_entry().
> 
> Packaging the call_single_queue logic makes the code less horrible, but it
> does mix up the event ordering...

Keeps em sharp ;-)

> > +		return;
> > +	}
> > +
> > +	raw_smp_call_single_queue(cpu, node);
> >  }
> >
> >  /*
> > @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
> >                * number of CPUs might be zero due to concurrent changes to the
> >                * provided mask.
> >                */
> > -		if (nr_cpus == 1)
> > +		if (nr_cpus == 1) {
> > +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
> >                       send_call_function_single_ipi(last_cpu);
> 
> This'll yield an IPI event even if no IPI is sent due to the idle task
> polling, no?

Oh, right..

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18  9:12         ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-18  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Daniel Bristot de Oliveira, Marcelo Tosatti,
	linux-kernel, linux-alpha, linuxppc-dev, David S. Miller

On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:

> > +	if (trace_ipi_send_cpumask_enabled()) {
> > +		call_single_data_t *csd;
> > +		smp_call_func_t func;
> > +
> > +		csd = container_of(node, call_single_data_t, node.llist);
> > +
> > +		func = sched_ttwu_pending;
> > +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> > +			func = csd->func;
> > +
> > +		if (raw_smp_call_single_queue(cpu, node))
> > +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
> 
> So I went with the tracepoint being placed *before* the actual IPI gets
> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
> e.g. trace_call_function_single_entry().
> 
> Packaging the call_single_queue logic makes the code less horrible, but it
> does mix up the event ordering...

Keeps em sharp ;-)

> > +		return;
> > +	}
> > +
> > +	raw_smp_call_single_queue(cpu, node);
> >  }
> >
> >  /*
> > @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
> >                * number of CPUs might be zero due to concurrent changes to the
> >                * provided mask.
> >                */
> > -		if (nr_cpus = 1)
> > +		if (nr_cpus = 1) {
> > +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
> >                       send_call_function_single_ipi(last_cpu);
> 
> This'll yield an IPI event even if no IPI is sent due to the idle task
> polling, no?

Oh, right..

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18  9:12         ` Peter Zijlstra
  0 siblings, 0 replies; 131+ messages in thread
From: Peter Zijlstra @ 2022-11-18  9:12 UTC (permalink / raw)
  To: Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Daniel Bristot de Oliveira, Marcelo Tosatti,
	Frederic Weisbecker, Ingo Molnar

On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:

> > +	if (trace_ipi_send_cpumask_enabled()) {
> > +		call_single_data_t *csd;
> > +		smp_call_func_t func;
> > +
> > +		csd = container_of(node, call_single_data_t, node.llist);
> > +
> > +		func = sched_ttwu_pending;
> > +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
> > +			func = csd->func;
> > +
> > +		if (raw_smp_call_single_queue(cpu, node))
> > +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
> 
> So I went with the tracepoint being placed *before* the actual IPI gets
> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
> e.g. trace_call_function_single_entry().
> 
> Packaging the call_single_queue logic makes the code less horrible, but it
> does mix up the event ordering...

Keeps em sharp ;-)

> > +		return;
> > +	}
> > +
> > +	raw_smp_call_single_queue(cpu, node);
> >  }
> >
> >  /*
> > @@ -983,10 +1017,13 @@ static void smp_call_function_many_cond(
> >                * number of CPUs might be zero due to concurrent changes to the
> >                * provided mask.
> >                */
> > -		if (nr_cpus == 1)
> > +		if (nr_cpus == 1) {
> > +			trace_ipi_send_cpumask(cpumask_of(last_cpu), _RET_IP_, func);
> >                       send_call_function_single_ipi(last_cpu);
> 
> This'll yield an IPI event even if no IPI is sent due to the idle task
> polling, no?

Oh, right..

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
  2022-11-18  9:12         ` Peter Zijlstra
                             ` (5 preceding siblings ...)
  (?)
@ 2022-11-18 16:42           ` Daniel Bristot de Oliveira
  -1 siblings, 0 replies; 131+ messages in thread
From: Daniel Bristot de Oliveira @ 2022-11-18 16:42 UTC (permalink / raw)
  To: Peter Zijlstra, Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Marcelo Tosatti, Frederic Weisbecker, Ingo Molnar,
	Borislav Petkov, Dave Hansen, H. Peter Anvin, Marc Zyngier,
	Mark Rutland, Russell King, Nicholas Piggin, Guo Ren,
	David S. Miller

On 11/18/22 10:12, Peter Zijlstra wrote:
> On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:
> 
>>> +	if (trace_ipi_send_cpumask_enabled()) {
>>> +		call_single_data_t *csd;
>>> +		smp_call_func_t func;
>>> +
>>> +		csd = container_of(node, call_single_data_t, node.llist);
>>> +
>>> +		func = sched_ttwu_pending;
>>> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
>>> +			func = csd->func;
>>> +
>>> +		if (raw_smp_call_single_queue(cpu, node))
>>> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
>> So I went with the tracepoint being placed *before* the actual IPI gets
>> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
>> e.g. trace_call_function_single_entry().
>>
>> Packaging the call_single_queue logic makes the code less horrible, but it
>> does mix up the event ordering...
> Keeps em sharp ;-)
> 

Having the trace before the IPI avoids the (non ideal) case where the trace stops because of
an IPI execution before we have trace about who sent it... :-(.

-- Daniel


^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18 16:42           ` Daniel Bristot de Oliveira
  0 siblings, 0 replies; 131+ messages in thread
From: Daniel Bristot de Oliveira @ 2022-11-18 16:42 UTC (permalink / raw)
  To: Peter Zijlstra, Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Marcelo Tosatti, linux-kernel, linux-alpha,
	linuxppc-dev, David S. Miller

On 11/18/22 10:12, Peter Zijlstra wrote:
> On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:
> 
>>> +	if (trace_ipi_send_cpumask_enabled()) {
>>> +		call_single_data_t *csd;
>>> +		smp_call_func_t func;
>>> +
>>> +		csd = container_of(node, call_single_data_t, node.llist);
>>> +
>>> +		func = sched_ttwu_pending;
>>> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
>>> +			func = csd->func;
>>> +
>>> +		if (raw_smp_call_single_queue(cpu, node))
>>> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
>> So I went with the tracepoint being placed *before* the actual IPI gets
>> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
>> e.g. trace_call_function_single_entry().
>>
>> Packaging the call_single_queue logic makes the code less horrible, but it
>> does mix up the event ordering...
> Keeps em sharp ;-)
> 

Having the trace before the IPI avoids the (non ideal) case where the trace stops because of
an IPI execution before we have trace about who sent it... :-(.

-- Daniel


^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18 16:42           ` Daniel Bristot de Oliveira
  0 siblings, 0 replies; 131+ messages in thread
From: Daniel Bristot de Oliveira @ 2022-11-18 16:42 UTC (permalink / raw)
  To: Peter Zijlstra, Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Marcelo Tosatti, Frederic Weisbecker, Ingo Molnar,
	Borislav Petkov, Dave Hansen, H. Peter Anvin, Marc Zyngier,
	Mark Rutland, Russell King, Nicholas Piggin, Guo Ren,
	David S. Miller

On 11/18/22 10:12, Peter Zijlstra wrote:
> On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:
> 
>>> +	if (trace_ipi_send_cpumask_enabled()) {
>>> +		call_single_data_t *csd;
>>> +		smp_call_func_t func;
>>> +
>>> +		csd = container_of(node, call_single_data_t, node.llist);
>>> +
>>> +		func = sched_ttwu_pending;
>>> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
>>> +			func = csd->func;
>>> +
>>> +		if (raw_smp_call_single_queue(cpu, node))
>>> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
>> So I went with the tracepoint being placed *before* the actual IPI gets
>> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
>> e.g. trace_call_function_single_entry().
>>
>> Packaging the call_single_queue logic makes the code less horrible, but it
>> does mix up the event ordering...
> Keeps em sharp ;-)
> 

Having the trace before the IPI avoids the (non ideal) case where the trace stops because of
an IPI execution before we have trace about who sent it... :-(.

-- Daniel


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18 16:42           ` Daniel Bristot de Oliveira
  0 siblings, 0 replies; 131+ messages in thread
From: Daniel Bristot de Oliveira @ 2022-11-18 16:42 UTC (permalink / raw)
  To: Peter Zijlstra, Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, Thomas Gleixner, linux-arm-kernel,
	linux-parisc, Marcelo Tosatti, linux-kernel, linux-alpha,
	linuxppc-dev, David S. Miller

On 11/18/22 10:12, Peter Zijlstra wrote:
> On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:
> 
>>> +	if (trace_ipi_send_cpumask_enabled()) {
>>> +		call_single_data_t *csd;
>>> +		smp_call_func_t func;
>>> +
>>> +		csd = container_of(node, call_single_data_t, node.llist);
>>> +
>>> +		func = sched_ttwu_pending;
>>> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
>>> +			func = csd->func;
>>> +
>>> +		if (raw_smp_call_single_queue(cpu, node))
>>> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
>> So I went with the tracepoint being placed *before* the actual IPI gets
>> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
>> e.g. trace_call_function_single_entry().
>>
>> Packaging the call_single_queue logic makes the code less horrible, but it
>> does mix up the event ordering...
> Keeps em sharp ;-)
> 

Having the trace before the IPI avoids the (non ideal) case where the trace stops because of
an IPI execution before we have trace about who sent it... :-(.

-- Daniel


^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18 16:42           ` Daniel Bristot de Oliveira
  0 siblings, 0 replies; 131+ messages in thread
From: Daniel Bristot de Oliveira @ 2022-11-18 16:42 UTC (permalink / raw)
  To: Peter Zijlstra, Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Marcelo Tosatti, Frederic Weisbecker, Ingo Molnar,
	Borislav Petkov, Dave Hansen, H. Peter Anvin, Marc Zyngier,
	Mark Rutland, Russell King, Nicholas Piggin, Guo Ren,
	David S. Miller

On 11/18/22 10:12, Peter Zijlstra wrote:
> On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:
> 
>>> +	if (trace_ipi_send_cpumask_enabled()) {
>>> +		call_single_data_t *csd;
>>> +		smp_call_func_t func;
>>> +
>>> +		csd = container_of(node, call_single_data_t, node.llist);
>>> +
>>> +		func = sched_ttwu_pending;
>>> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
>>> +			func = csd->func;
>>> +
>>> +		if (raw_smp_call_single_queue(cpu, node))
>>> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
>> So I went with the tracepoint being placed *before* the actual IPI gets
>> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
>> e.g. trace_call_function_single_entry().
>>
>> Packaging the call_single_queue logic makes the code less horrible, but it
>> does mix up the event ordering...
> Keeps em sharp ;-)
> 

Having the trace before the IPI avoids the (non ideal) case where the trace stops because of
an IPI execution before we have trace about who sent it... :-(.

-- Daniel


_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18 16:42           ` Daniel Bristot de Oliveira
  0 siblings, 0 replies; 131+ messages in thread
From: Daniel Bristot de Oliveira @ 2022-11-18 16:42 UTC (permalink / raw)
  To: Peter Zijlstra, Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Marcelo Tosatti, Frederic Weisbecker, Ingo Molnar,
	Borislav Petkov, Dave Hansen, H. Peter Anvin, Marc Zyngier,
	Mark Rutland, Russell King, Nicholas Piggin, Guo Ren,
	David S. Miller

On 11/18/22 10:12, Peter Zijlstra wrote:
> On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:
> 
>>> +	if (trace_ipi_send_cpumask_enabled()) {
>>> +		call_single_data_t *csd;
>>> +		smp_call_func_t func;
>>> +
>>> +		csd = container_of(node, call_single_data_t, node.llist);
>>> +
>>> +		func = sched_ttwu_pending;
>>> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
>>> +			func = csd->func;
>>> +
>>> +		if (raw_smp_call_single_queue(cpu, node))
>>> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
>> So I went with the tracepoint being placed *before* the actual IPI gets
>> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
>> e.g. trace_call_function_single_entry().
>>
>> Packaging the call_single_queue logic makes the code less horrible, but it
>> does mix up the event ordering...
> Keeps em sharp ;-)
> 

Having the trace before the IPI avoids the (non ideal) case where the trace stops because of
an IPI execution before we have trace about who sent it... :-(.

-- Daniel


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18 16:42           ` Daniel Bristot de Oliveira
  0 siblings, 0 replies; 131+ messages in thread
From: Daniel Bristot de Oliveira @ 2022-11-18 16:42 UTC (permalink / raw)
  To: Peter Zijlstra, Valentin Schneider
  Cc: linux-alpha, linux-kernel, linux-snps-arc, linux-arm-kernel,
	linux-csky, linux-hexagon, linux-ia64, loongarch, linux-mips,
	openrisc, linux-parisc, linuxppc-dev, linux-riscv, linux-s390,
	linux-sh, sparclinux, linux-xtensa, x86, Paul E. McKenney,
	Steven Rostedt, Thomas Gleixner, Sebastian Andrzej Siewior,
	Juri Lelli, Marcelo Tosatti, Frederic Weisbecker, Ingo Molnar,
	Borislav Petkov, Dave Hansen, H. Peter Anvin, Marc Zyngier,
	Mark Rutland, Russell King, Nicholas Piggin, Guo Ren,
	David S. Miller

On 11/18/22 10:12, Peter Zijlstra wrote:
> On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:
> 
>>> +	if (trace_ipi_send_cpumask_enabled()) {
>>> +		call_single_data_t *csd;
>>> +		smp_call_func_t func;
>>> +
>>> +		csd = container_of(node, call_single_data_t, node.llist);
>>> +
>>> +		func = sched_ttwu_pending;
>>> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
>>> +			func = csd->func;
>>> +
>>> +		if (raw_smp_call_single_queue(cpu, node))
>>> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
>> So I went with the tracepoint being placed *before* the actual IPI gets
>> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
>> e.g. trace_call_function_single_entry().
>>
>> Packaging the call_single_queue logic makes the code less horrible, but it
>> does mix up the event ordering...
> Keeps em sharp ;-)
> 

Having the trace before the IPI avoids the (non ideal) case where the trace stops because of
an IPI execution before we have trace about who sent it... :-(.

-- Daniel

^ permalink raw reply	[flat|nested] 131+ messages in thread
* Re: [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI
@ 2022-11-18 16:42           ` Daniel Bristot de Oliveira
  0 siblings, 0 replies; 131+ messages in thread
From: Daniel Bristot de Oliveira @ 2022-11-18 16:42 UTC (permalink / raw)
  To: Peter Zijlstra, Valentin Schneider
  Cc: Juri Lelli, Mark Rutland, linux-ia64, linux-sh,
	Sebastian Andrzej Siewior, Dave Hansen, linux-mips, Guo Ren,
	H. Peter Anvin, sparclinux, linux-riscv, linux-s390,
	Marc Zyngier, linux-hexagon, x86, Russell King, linux-csky,
	Ingo Molnar, linux-snps-arc, linux-xtensa, Paul E. McKenney,
	Frederic Weisbecker, Steven Rostedt, openrisc, Borislav Petkov,
	Nicholas Piggin, loongarch, T

On 11/18/22 10:12, Peter Zijlstra wrote:
> On Thu, Nov 17, 2022 at 02:45:29PM +0000, Valentin Schneider wrote:
> 
>>> +	if (trace_ipi_send_cpumask_enabled()) {
>>> +		call_single_data_t *csd;
>>> +		smp_call_func_t func;
>>> +
>>> +		csd = container_of(node, call_single_data_t, node.llist);
>>> +
>>> +		func = sched_ttwu_pending;
>>> +		if (CSD_TYPE(csd) != CSD_TYPE_TTWU)
>>> +			func = csd->func;
>>> +
>>> +		if (raw_smp_call_single_queue(cpu, node))
>>> +			trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, func);
>> So I went with the tracepoint being placed *before* the actual IPI gets
>> sent to have a somewhat sane ordering between trace_ipi_send_cpumask() and
>> e.g. trace_call_function_single_entry().
>>
>> Packaging the call_single_queue logic makes the code less horrible, but it
>> does mix up the event ordering...
> Keeps em sharp ;-)
> 

Having the trace before the IPI avoids the (non ideal) case where the trace stops because of
an IPI execution before we have trace about who sent it... :-(.

-- Daniel


^ permalink raw reply	[flat|nested] 131+ messages in thread
end of thread, other threads:[~2022-11-18 16:45 UTC | newest]

Thread overview: 131+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-11-02 18:29 [RFC PATCH v2 0/8] Generic IPI sending tracepoint Valentin Schneider
2022-11-02 18:29 ` Valentin Schneider
2022-11-02 18:29 ` Valentin Schneider
2022-11-02 18:29 ` Valentin Schneider
2022-11-02 18:29 ` Valentin Schneider
2022-11-02 18:29 ` Valentin Schneider
2022-11-02 18:29 ` [RFC PATCH v2 1/8] DO-NOT-MERGE: tracing: Add __cpumask to denote a trace event field that is a cpumask_t Valentin Schneider
2022-11-02 18:29   ` [RFC PATCH v2 1/8] DO-NOT-MERGE: tracing: Add __cpumask to denote a trace event field that is a cpum Valentin Schneider
2022-11-02 18:29   ` [RFC PATCH v2 1/8] DO-NOT-MERGE: tracing: Add __cpumask to denote a trace event field that is a cpumask_t Valentin Schneider
2022-11-02 18:29   ` Valentin Schneider
2022-11-02 18:29   ` Valentin Schneider
2022-11-02 18:29   ` Valentin Schneider
2022-11-02 18:33 ` [RFC PATCH v2 2/8] trace: Add trace_ipi_send_cpumask() Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33 ` [RFC PATCH v2 3/8] sched, smp: Trace IPIs sent via send_call_function_single_ipi() Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33 ` [RFC PATCH v2 4/8] smp: Trace IPIs sent via arch_send_call_function_ipi_mask() Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-17  9:08   ` Peter Zijlstra
2022-11-17  9:08     ` Peter Zijlstra
2022-11-17  9:08     ` Peter Zijlstra
2022-11-17  9:08     ` Peter Zijlstra
2022-11-17  9:08     ` Peter Zijlstra
2022-11-17  9:08     ` Peter Zijlstra
2022-11-17  9:08     ` Peter Zijlstra
2022-11-17  9:08     ` Peter Zijlstra
2022-11-17 14:23     ` Valentin Schneider
2022-11-17 14:23       ` Valentin Schneider
2022-11-17 14:23       ` Valentin Schneider
2022-11-17 14:23       ` Valentin Schneider
2022-11-17 14:23       ` Valentin Schneider
2022-11-17 14:23       ` Valentin Schneider
2022-11-17 14:23       ` Valentin Schneider
2022-11-02 18:33 ` [RFC PATCH v2 5/8] irq_work: Trace self-IPIs sent via arch_irq_work_raise() Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-17  9:10   ` Peter Zijlstra
2022-11-17  9:10     ` Peter Zijlstra
2022-11-17  9:10     ` Peter Zijlstra
2022-11-17  9:10     ` Peter Zijlstra
2022-11-17  9:10     ` Peter Zijlstra
2022-11-17  9:10     ` Peter Zijlstra
2022-11-17  9:10     ` Peter Zijlstra
2022-11-17  9:10     ` Peter Zijlstra
2022-11-02 18:33 ` [RFC PATCH v2 6/8] treewide: Trace IPIs sent via smp_send_reschedule() Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-17  9:12   ` Peter Zijlstra
2022-11-17  9:12     ` Peter Zijlstra
2022-11-17  9:12     ` Peter Zijlstra
2022-11-17  9:12     ` Peter Zijlstra
2022-11-17  9:12     ` Peter Zijlstra
2022-11-17  9:12     ` Peter Zijlstra
2022-11-17  9:12     ` Peter Zijlstra
2022-11-17  9:12     ` Peter Zijlstra
2022-11-17 14:24     ` Valentin Schneider
2022-11-17 14:24       ` Valentin Schneider
2022-11-17 14:24       ` Valentin Schneider
2022-11-17 14:24       ` Valentin Schneider
2022-11-17 14:24       ` Valentin Schneider
2022-11-17 14:24       ` Valentin Schneider
2022-11-02 18:33 ` [RFC PATCH v2 7/8] smp: reword smp call IPI comment Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33 ` [RFC PATCH v2 8/8] sched, smp: Trace smp callback causing an IPI Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-02 18:33   ` Valentin Schneider
2022-11-17 14:12   ` Peter Zijlstra
2022-11-17 14:12     ` Peter Zijlstra
2022-11-17 14:12     ` Peter Zijlstra
2022-11-17 14:12     ` Peter Zijlstra
2022-11-17 14:12     ` Peter Zijlstra
2022-11-17 14:12     ` Peter Zijlstra
2022-11-17 14:12     ` Peter Zijlstra
2022-11-17 14:12     ` Peter Zijlstra
2022-11-17 14:45     ` Valentin Schneider
2022-11-17 14:45       ` Valentin Schneider
2022-11-17 14:45       ` Valentin Schneider
2022-11-17 14:45       ` Valentin Schneider
2022-11-17 14:45       ` Valentin Schneider
2022-11-17 14:45       ` Valentin Schneider
2022-11-17 14:45       ` Valentin Schneider
2022-11-17 14:45       ` Valentin Schneider
2022-11-18  9:12       ` Peter Zijlstra
2022-11-18  9:12         ` Peter Zijlstra
2022-11-18  9:12         ` Peter Zijlstra
2022-11-18  9:12         ` Peter Zijlstra
2022-11-18  9:12         ` Peter Zijlstra
2022-11-18  9:12         ` Peter Zijlstra
2022-11-18  9:12         ` Peter Zijlstra
2022-11-18  9:12         ` Peter Zijlstra
2022-11-18 16:42         ` Daniel Bristot de Oliveira
2022-11-18 16:42           ` Daniel Bristot de Oliveira
2022-11-18 16:42           ` Daniel Bristot de Oliveira
2022-11-18 16:42           ` Daniel Bristot de Oliveira
2022-11-18 16:42           ` Daniel Bristot de Oliveira
2022-11-18 16:42           ` Daniel Bristot de Oliveira
2022-11-18 16:42           ` Daniel Bristot de Oliveira
2022-11-18 16:42           ` Daniel Bristot de Oliveira
2022-11-14 17:27 ` [RFC PATCH v2 0/8] Generic IPI sending tracepoint Steven Rostedt
2022-11-14 17:27   ` Steven Rostedt
2022-11-14 17:27   ` Steven Rostedt
2022-11-14 17:27   ` Steven Rostedt
2022-11-14 17:27   ` Steven Rostedt
2022-11-14 17:27   ` Steven Rostedt
2022-11-14 17:27   ` Steven Rostedt
2022-11-14 17:27   ` Steven Rostedt

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