[RFC][PATCH 00/17 v2] tracing: Use TRACE_DEFINE_ENUM() to show enum values

[RFC][PATCH 00/17 v2] tracing: Use TRACE_DEFINE_ENUM() to show enum values

[Steven Rostedt]

As there are many tracepoints that use __print_symbolic() to translate
numbers into ASCII strings, and several of these translate enums as
well, it causes a problem for user space tools that read the tracepoint
format files and have to translate the binary data to their associated
strings.

For example, with the tlb_flush tracepoint, we have this in the format
file:

print fmt: "pages:%ld reason:%s (%d)", REC->pages,
 __print_symbolic(REC->reason,
   { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" },
   { TLB_REMOTE_SHOOTDOWN, "remote shootdown" },
   { TLB_LOCAL_SHOOTDOWN, "local shootdown" },
   { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }), REC->reason

Now, userspace does not know what the value of TLB_REMOTE_SHOOTDOWN is.
To solve this, a new macro is created as a helper to allow tracepoints
to export enums they use to userspace. This macro is called,
TRACE_DEFINE_ENUM(), such that

 TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN);

will convert the "print fmt"s in the format files to its actual value
and no longer display the enum name.

On boot up (or module load), the enums saved via TRACE_DEFINE_ENUM()
will be searched for in the TP_printk()s of the tracepoints. Logic
knows enough to ignore quoted text.

For debugging, a new file is still added in the tracing directory
to show what enums were added, their values and the TRACE_SYSTEM that
added them:

 # cat /sys/kernel/debug/tracing/enum_map
TLB_LOCAL_MM_SHOOTDOWN 3 (tlb)
TLB_LOCAL_SHOOTDOWN 2 (tlb)
TLB_REMOTE_SHOOTDOWN 1 (tlb)
TLB_FLUSH_ON_TASK_SWITCH 0 (tlb)

And the output of the tlb_flush format is now:

print fmt: "pages:%ld reason:%s (%d)", REC->pages,
 __print_symbolic(REC->reason,
   { 0, "flush on task switch" },
   { 1, "remote shootdown" },
   { 2, "local shootdown" },
   { 3, "local mm shootdown" }), REC->reason

And userspace tools can easily parse that without special handling.

Local SHA1: a6862181206543b6493c73690f322868c86de0ea


Steven Rostedt (Red Hat) (17):
      tracing: Add TRACE_SYSTEM_VAR to intel-sst
      tracing: Add TRACE_SYSTEM_VAR to kvm-s390
      tracing: Add TRACE_SYSTEM_VAR to xhci-hcd
      tracing: Give system name a pointer
      tracing: Update trace-event-sample with TRACE_SYSTEM_VAR documentation
      tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values
      tracing: Allow for modules to export their trace enums as well
      tracing/samples: Update the trace-event-sample.h with TRACE_DEFINE_ENUM()
      tracing: Show the mapped enums in enum_map file
      x86/tlb/trace: Export enums in used by tlb_flush tracepoint
      net/9p/tracing: Export enums in tracepoints to userspace
      f2fs: Export the enums in the tracepoints to userspace
      irq/tracing: Export enums in tracepoints to user space
      mm: tracing: Export enums in tracepoints to user space
      SUNRPC: Export enums in tracepoints to user space
      v4l: Export enums used by tracepoints to user space
      writeback: Export enums used by tracepoint to user space

----
 arch/s390/kvm/trace-s390.h                 |   7 +
 drivers/usb/host/xhci-trace.h              |   7 +
 include/asm-generic/vmlinux.lds.h          |   5 +-
 include/linux/ftrace_event.h               |   4 +-
 include/linux/module.h                     |   2 +
 include/linux/tracepoint.h                 |   8 +
 include/trace/events/9p.h                  | 157 ++++++++--------
 include/trace/events/f2fs.h                |  30 ++++
 include/trace/events/intel-sst.h           |   7 +
 include/trace/events/irq.h                 |  39 ++--
 include/trace/events/migrate.h             |  42 +++--
 include/trace/events/sunrpc.h              |  62 +++++--
 include/trace/events/tlb.h                 |  30 +++-
 include/trace/events/v4l2.h                |  75 +++++---
 include/trace/events/writeback.h           |  33 +++-
 include/trace/ftrace.h                     |  41 ++++-
 kernel/module.c                            |   3 +
 kernel/trace/trace.c                       | 276 ++++++++++++++++++++++++++++-
 kernel/trace/trace.h                       |   2 +
 kernel/trace/trace_events.c                |  98 +++++++++-
 samples/trace_events/trace-events-sample.h |  84 ++++++++-
 21 files changed, 853 insertions(+), 159 deletions(-)

[RFC][PATCH 01/17 v2] tracing: Add TRACE_SYSTEM_VAR to intel-sst

[Steven Rostedt]

[-- Attachment #1: 0001-tracing-Add-TRACE_SYSTEM_VAR-to-intel-sst.patch --]
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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

New code will require TRACE_SYSTEM to be a valid C variable name,
but some tracepoints have TRACE_SYSTEM with '-' and not '_', so
it can not be used. Instead, add a TRACE_SYSTEM_VAR that can
give the tracing infrastructure a unique name for the trace system.

Cc: Mark Brown <broonie@linaro.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/intel-sst.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/trace/events/intel-sst.h b/include/trace/events/intel-sst.h
index 76c72d3f1902..edc24e6dea1b 100644
--- a/include/trace/events/intel-sst.h
+++ b/include/trace/events/intel-sst.h
@@ -1,6 +1,13 @@
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM intel-sst
 
+/*
+ * The TRACE_SYSTEM_VAR defaults to TRACE_SYSTEM, but must be a
+ * legitimate C variable. It is not exported to user space.
+ */
+#undef TRACE_SYSTEM_VAR
+#define TRACE_SYSTEM_VAR intel_sst
+
 #if !defined(_TRACE_INTEL_SST_H) || defined(TRACE_HEADER_MULTI_READ)
 #define _TRACE_INTEL_SST_H
 
-- 
2.1.4

Re: [RFC][PATCH 01/17 v2] tracing: Add TRACE_SYSTEM_VAR to intel-sst

[Steven Rostedt]

On Thu, 2 Apr 2015 10:16:22 +0100
Mark Brown <broonie@linaro.org> wrote:

> On 2 April 2015 at 02:56, Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> > From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> >
> > New code will require TRACE_SYSTEM to be a valid C variable name,
> > but some tracepoints have TRACE_SYSTEM with '-' and not '_', so
> > it can not be used. Instead, add a TRACE_SYSTEM_VAR that can
> > give the tracing infrastructure a unique name for the trace system.
> >
> > Cc: Mark Brown <broonie@linaro.org>
> >
> 
> I'm not sure why you're sending this to my work address but please use
> broonie@kernel.org for anything upstream (it's what's in MAINTAINERS and
> what I've been using pretty consistently for e-mail).
> 

Sorry, I got that from git log include/trace/events/intel-sst.h

I couldn't find anything in MAINTAINERS about that file, but I didn't
look for your name though.

-- Steve

Re: [RFC][PATCH 01/17 v2] tracing: Add TRACE_SYSTEM_VAR to intel-sst

[Steven Rostedt]

On Thu, 2 Apr 2015 09:32:49 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Thu, 2 Apr 2015 10:16:22 +0100
> Mark Brown <broonie@linaro.org> wrote:
> 
> > On 2 April 2015 at 02:56, Steven Rostedt <rostedt@goodmis.org> wrote:
> > 
> > > From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> > >
> > > New code will require TRACE_SYSTEM to be a valid C variable name,
> > > but some tracepoints have TRACE_SYSTEM with '-' and not '_', so
> > > it can not be used. Instead, add a TRACE_SYSTEM_VAR that can
> > > give the tracing infrastructure a unique name for the trace system.
> > >
> > > Cc: Mark Brown <broonie@linaro.org>
> > >
> > 
> > I'm not sure why you're sending this to my work address but please use
> > broonie@kernel.org for anything upstream (it's what's in MAINTAINERS and
> > what I've been using pretty consistently for e-mail).
> > 
> 
> Sorry, I got that from git log include/trace/events/intel-sst.h
> 
> I couldn't find anything in MAINTAINERS about that file, but I didn't
> look for your name though.
> 

BTW, was that considered an Acked-by?

-- Steve

Re: [RFC][PATCH 01/17 v2] tracing: Add TRACE_SYSTEM_VAR to intel-sst

[Mark Brown]

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On Thu, Apr 02, 2015 at 09:33:41AM -0400, Steven Rostedt wrote:
> Steven Rostedt <rostedt@goodmis.org> wrote:

> > I couldn't find anything in MAINTAINERS about that file, but I didn't
> > look for your name though.

> BTW, was that considered an Acked-by?

I guess, you probably want to ping the Intel guys though since it's them
that would be affected by the interface change.

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Re: [RFC][PATCH 01/17 v2] tracing: Add TRACE_SYSTEM_VAR to intel-sst

[Steven Rostedt]

On Thu, 2 Apr 2015 14:40:33 +0100
Mark Brown <broonie@kernel.org> wrote:

> On Thu, Apr 02, 2015 at 09:33:41AM -0400, Steven Rostedt wrote:
> > Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> > > I couldn't find anything in MAINTAINERS about that file, but I didn't
> > > look for your name though.
> 
> > BTW, was that considered an Acked-by?
> 
> I guess, you probably want to ping the Intel guys though since it's them
> that would be affected by the interface change.

Actually, there's no interface change. This is the work-around patch to
that. It's only internal to the kernel and userspace does not see any
difference.

I just needed a unique TRACE_SYSTEM name that was also a valid C
variable, and now use TRACE_SYSTEM_VAR.

The ftrace code now has:

#ifndef TRACE_SYSTEM_VAR
#define TRACE_SYSTEM_VAR TRACE_SYSTEM
#endif

And this allows trace headers (like intel-sst.h) to have a different
VAR variable from the TRACE_SYSTEM name:

#define TRACE_SYSTEM intel-ssl

#define TRACE_SYSTEM_VAR intel_ssl

This lets me use something that will work and not need to change what
the user space sees.

-- Steve

Re: [RFC][PATCH 01/17 v2] tracing: Add TRACE_SYSTEM_VAR to intel-sst

[Mark Brown]

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On Thu, Apr 02, 2015 at 09:49:34AM -0400, Steven Rostedt wrote:
> Mark Brown <broonie@kernel.org> wrote:

> > I guess, you probably want to ping the Intel guys though since it's them
> > that would be affected by the interface change.

> Actually, there's no interface change. This is the work-around patch to
> that. It's only internal to the kernel and userspace does not see any
> difference.

Ah, OK - that's definitely not an issue then.

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Re: [RFC][PATCH 01/17 v2] tracing: Add TRACE_SYSTEM_VAR to intel-sst

[Steven Rostedt]

On Thu, 2 Apr 2015 14:59:33 +0100
Mark Brown <broonie@kernel.org> wrote:

> On Thu, Apr 02, 2015 at 09:49:34AM -0400, Steven Rostedt wrote:
> > Mark Brown <broonie@kernel.org> wrote:
> 
> > > I guess, you probably want to ping the Intel guys though since it's them
> > > that would be affected by the interface change.
> 
> > Actually, there's no interface change. This is the work-around patch to
> > that. It's only internal to the kernel and userspace does not see any
> > difference.
> 
> Ah, OK - that's definitely not an issue then.

So that's an Acked-by then? :-)

-- Steve

Re: [RFC][PATCH 01/17 v2] tracing: Add TRACE_SYSTEM_VAR to intel-sst

[Mark Brown]

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On Thu, Apr 02, 2015 at 10:03:24AM -0400, Steven Rostedt wrote:

> So that's an Acked-by then? :-)

Sure.

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[RFC][PATCH 02/17 v2] tracing: Add TRACE_SYSTEM_VAR to kvm-s390

[Steven Rostedt]

[-- Attachment #1: 0002-tracing-Add-TRACE_SYSTEM_VAR-to-kvm-s390.patch --]
[-- Type: text/plain, Size: 1225 bytes --]

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

New code will require TRACE_SYSTEM to be a valid C variable name,
but some tracepoints have TRACE_SYSTEM with '-' and not '_', so
it can not be used. Instead, add a TRACE_SYSTEM_VAR that can
give the tracing infrastructure a unique name for the trace system.

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 arch/s390/kvm/trace-s390.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/s390/kvm/trace-s390.h b/arch/s390/kvm/trace-s390.h
index 653a7ec09ef5..3208d33a48cb 100644
--- a/arch/s390/kvm/trace-s390.h
+++ b/arch/s390/kvm/trace-s390.h
@@ -10,6 +10,13 @@
 #define TRACE_INCLUDE_FILE trace-s390
 
 /*
+ * The TRACE_SYSTEM_VAR defaults to TRACE_SYSTEM, but must be a
+ * legitimate C variable. It is not exported to user space.
+ */
+#undef TRACE_SYSTEM_VAR
+#define TRACE_SYSTEM_VAR kvm_s390
+
+/*
  * Trace point for the creation of the kvm instance.
  */
 TRACE_EVENT(kvm_s390_create_vm,
-- 
2.1.4

Re: [RFC][PATCH 02/17 v2] tracing: Add TRACE_SYSTEM_VAR to kvm-s390

[Cornelia Huck]

On Wed, 01 Apr 2015 21:56:50 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> 
> New code will require TRACE_SYSTEM to be a valid C variable name,
> but some tracepoints have TRACE_SYSTEM with '-' and not '_', so
> it can not be used. Instead, add a TRACE_SYSTEM_VAR that can
> give the tracing infrastructure a unique name for the trace system.
> 
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
> Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
> Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
>  arch/s390/kvm/trace-s390.h | 7 +++++++
>  1 file changed, 7 insertions(+)

Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>

[RFC][PATCH 03/17 v2] tracing: Add TRACE_SYSTEM_VAR to xhci-hcd

[Steven Rostedt]

[-- Attachment #1: 0003-tracing-Add-TRACE_SYSTEM_VAR-to-xhci-hcd.patch --]
[-- Type: text/plain, Size: 1103 bytes --]

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

New code will require TRACE_SYSTEM to be a valid C variable name,
but some tracepoints have TRACE_SYSTEM with '-' and not '_', so
it can not be used. Instead, add a TRACE_SYSTEM_VAR that can
give the tracing infrastructure a unique name for the trace system.

Cc: Xenia Ragiadakou <burzalodowa@gmail.com>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 drivers/usb/host/xhci-trace.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/usb/host/xhci-trace.h b/drivers/usb/host/xhci-trace.h
index dde3959b7a33..59c05653b2ea 100644
--- a/drivers/usb/host/xhci-trace.h
+++ b/drivers/usb/host/xhci-trace.h
@@ -14,6 +14,13 @@
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM xhci-hcd
 
+/*
+ * The TRACE_SYSTEM_VAR defaults to TRACE_SYSTEM, but must be a
+ * legitimate C variable. It is not exported to user space.
+ */
+#undef TRACE_SYSTEM_VAR
+#define TRACE_SYSTEM_VAR xhci_hcd
+
 #if !defined(__XHCI_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
 #define __XHCI_TRACE_H
 
-- 
2.1.4

[RFC][PATCH 04/17 v2] tracing: Give system name a pointer

[Steven Rostedt]

[-- Attachment #1: 0004-tracing-Give-system-name-a-pointer.patch --]
[-- Type: text/plain, Size: 2555 bytes --]

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

Normally the compiler will use the same pointer for a string throughout
the file. But there's no guarantee of that happening. Later changes will
require that all events have the same pointer to the system string.

Name the system string and have all events point to it.

Testing this, it did not increases the size of the text, except for the
notes section, which should not harm the real size any.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/ftrace_event.h |  2 +-
 include/trace/ftrace.h       | 19 +++++++++++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index c674ee8f7fca..62b8fac7ded5 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -202,7 +202,7 @@ enum trace_reg {
 struct ftrace_event_call;
 
 struct ftrace_event_class {
-	char			*system;
+	const char		*system;
 	void			*probe;
 #ifdef CONFIG_PERF_EVENTS
 	void			*perf_probe;
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 41bf65f04dd9..2f9b95b6d3fb 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -18,6 +18,21 @@
 
 #include <linux/ftrace_event.h>
 
+#ifndef TRACE_SYSTEM_VAR
+#define TRACE_SYSTEM_VAR TRACE_SYSTEM
+#endif
+
+#define __app__(x, y) str__##x##y
+#define __app(x, y) __app__(x, y)
+
+#define TRACE_SYSTEM_STRING __app(TRACE_SYSTEM_VAR,__trace_system_name)
+
+#define TRACE_MAKE_SYSTEM_STR()				\
+	static const char TRACE_SYSTEM_STRING[] =	\
+		__stringify(TRACE_SYSTEM)
+
+TRACE_MAKE_SYSTEM_STR();
+
 /*
  * DECLARE_EVENT_CLASS can be used to add a generic function
  * handlers for events. That is, if all events have the same
@@ -105,7 +120,6 @@
 
 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
 
-
 /*
  * Stage 2 of the trace events.
  *
@@ -692,7 +706,7 @@ static inline void ftrace_test_probe_##call(void)			\
 _TRACE_PERF_PROTO(call, PARAMS(proto));					\
 static const char print_fmt_##call[] = print;				\
 static struct ftrace_event_class __used __refdata event_class_##call = { \
-	.system			= __stringify(TRACE_SYSTEM),		\
+	.system			= TRACE_SYSTEM_STRING,			\
 	.define_fields		= ftrace_define_fields_##call,		\
 	.fields			= LIST_HEAD_INIT(event_class_##call.fields),\
 	.raw_init		= trace_event_raw_init,			\
@@ -735,6 +749,7 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call
 
 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
 
+#undef TRACE_SYSTEM_VAR
 
 #ifdef CONFIG_PERF_EVENTS
 
-- 
2.1.4

[RFC][PATCH 05/17 v2] tracing: Update trace-event-sample with TRACE_SYSTEM_VAR documentation

[Steven Rostedt]

[-- Attachment #1: 0005-tracing-Update-trace-event-sample-with-TRACE_SYSTEM_.patch --]
[-- Type: text/plain, Size: 1645 bytes --]

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

Add documentation about TRACE_SYSTEM needing to be alpha-numeric or with
underscores, and that if it is not, then the use of TRACE_SYSTEM_VAR is
required to make something that is.

An example of this is shown in samples/trace_events/trace-events-sample.h\x18

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 samples/trace_events/trace-events-sample.h | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index a2c8b02b6359..19405f18cc8a 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -22,7 +22,25 @@
  * protection, just like TRACE_INCLUDE_FILE.
  */
 #undef TRACE_SYSTEM
-#define TRACE_SYSTEM sample
+#define TRACE_SYSTEM sample-trace
+
+/*
+ * TRACE_SYSTEM is expected to be a C valid variable (alpha-numeric
+ * and underscore), although it may start with numbers. If for some
+ * reason it is not, you need to add the following lines:
+ */
+#undef TRACE_SYSTEM_VAR
+#define TRACE_SYSTEM_VAR sample_trace
+/*
+ * But the above is only needed if TRACE_SYSTEM is not alpha-numeric
+ * and underscored. By default, TRACE_SYSTEM_VAR will be equal to
+ * TRACE_SYSTEM. As TRACE_SYSTEM_VAR must be alpha-numeric, if
+ * TRACE_SYSTEM is not, then TRACE_SYSTEM_VAR must be defined with
+ * only alpha-numeric and underscores.
+ *
+ * The TRACE_SYSTEM_VAR is only used internally and not visible to
+ * user space.
+ */
 
 /*
  * Notice that this file is not protected like a normal header.
-- 
2.1.4

[RFC][PATCH 06/17 v2] tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values

[Steven Rostedt]

[-- Attachment #1: 0006-tracing-Add-TRACE_DEFINE_ENUM-macro-to-map-enums-to-.patch --]
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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Several tracepoints use the helper functions __print_symbolic() or
__print_flags() and pass in enums that do the mapping between the
binary data stored and the value to print. This works well for reading
the ASCII trace files, but when the data is read via userspace tools
such as perf and trace-cmd, the conversion of the binary value to a
human string format is lost if an enum is used, as userspace does not
have access to what the ENUM is.

For example, the tracepoint trace_tlb_flush() has:

 __print_symbolic(REC->reason,
    { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" },
    { TLB_REMOTE_SHOOTDOWN, "remote shootdown" },
    { TLB_LOCAL_SHOOTDOWN, "local shootdown" },
    { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" })

Which maps the enum values to the strings they represent. But perf and
trace-cmd do no know what value TLB_LOCAL_MM_SHOOTDOWN is, and would
not be able to map it.

With TRACE_DEFINE_ENUM(), developers can place these in the event header
files and ftrace will convert the enums to their values:

By adding:

 TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH);
 TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN);
 TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN);
 TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN);

 $ cat /sys/kernel/debug/tracing/events/tlb/tlb_flush/format
[...]
 __print_symbolic(REC->reason,
    { 0, "flush on task switch" },
    { 1, "remote shootdown" },
    { 2, "local shootdown" },
    { 3, "local mm shootdown" })

The above is what userspace expects to see, and tools do not need to
be modified to parse them.

Cc: Guilherme Cox <cox@computer.org>
Cc: Tony Luck <tony.luck@gmail.com>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/asm-generic/vmlinux.lds.h |  5 +-
 include/linux/ftrace_event.h      |  2 +-
 include/linux/tracepoint.h        |  8 ++++
 include/trace/ftrace.h            | 22 +++++++--
 kernel/trace/trace.c              | 43 +++++++++++++++++-
 kernel/trace/trace.h              |  2 +
 kernel/trace/trace_events.c       | 96 +++++++++++++++++++++++++++++++++++++++
 7 files changed, 172 insertions(+), 6 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index ac78910d7416..f8e8b34dc427 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -124,7 +124,10 @@
 #define FTRACE_EVENTS()	. = ALIGN(8);					\
 			VMLINUX_SYMBOL(__start_ftrace_events) = .;	\
 			*(_ftrace_events)				\
-			VMLINUX_SYMBOL(__stop_ftrace_events) = .;
+			VMLINUX_SYMBOL(__stop_ftrace_events) = .;	\
+			VMLINUX_SYMBOL(__start_ftrace_enum_maps) = .;	\
+			*(_ftrace_enum_map)				\
+			VMLINUX_SYMBOL(__stop_ftrace_enum_maps) = .;
 #else
 #define FTRACE_EVENTS()
 #endif
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 62b8fac7ded5..112cf49d9576 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -285,7 +285,7 @@ struct ftrace_event_call {
 		struct tracepoint	*tp;
 	};
 	struct trace_event	event;
-	const char		*print_fmt;
+	char			*print_fmt;
 	struct event_filter	*filter;
 	void			*mod;
 	void			*data;
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index c72851328ca9..a5f7f3ecafa3 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -36,6 +36,12 @@ struct tracepoint {
 	struct tracepoint_func __rcu *funcs;
 };
 
+struct trace_enum_map {
+	const char		*system;
+	const char		*enum_string;
+	unsigned long		enum_value;
+};
+
 extern int
 tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
 extern int
@@ -87,6 +93,8 @@ extern void syscall_unregfunc(void);
 
 #define PARAMS(args...) args
 
+#define TRACE_DEFINE_ENUM(x)
+
 #endif /* _LINUX_TRACEPOINT_H */
 
 /*
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 2f9b95b6d3fb..37d4b10b111d 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -33,6 +33,19 @@
 
 TRACE_MAKE_SYSTEM_STR();
 
+#undef TRACE_DEFINE_ENUM
+#define TRACE_DEFINE_ENUM(a)				\
+	static struct trace_enum_map __used __initdata	\
+	__##TRACE_SYSTEM##_##a =			\
+	{						\
+		.system = TRACE_SYSTEM_STRING,		\
+		.enum_string = #a,			\
+		.enum_value = a				\
+	};						\
+	static struct trace_enum_map __used		\
+	__attribute__((section("_ftrace_enum_map")))	\
+	*TRACE_SYSTEM##_##a = &__##TRACE_SYSTEM##_##a
+
 /*
  * DECLARE_EVENT_CLASS can be used to add a generic function
  * handlers for events. That is, if all events have the same
@@ -136,6 +149,9 @@ TRACE_MAKE_SYSTEM_STR();
  * The size of an array is also encoded, in the higher 16 bits of <item>.
  */
 
+#undef TRACE_DEFINE_ENUM
+#define TRACE_DEFINE_ENUM(a)
+
 #undef __field
 #define __field(type, item)
 
@@ -553,7 +569,7 @@ static inline notrace int ftrace_get_offsets_##call(			\
  *	.trace			= ftrace_raw_output_<call>, <-- stage 2
  * };
  *
- * static const char print_fmt_<call>[] = <TP_printk>;
+ * static char print_fmt_<call>[] = <TP_printk>;
  *
  * static struct ftrace_event_class __used event_class_<template> = {
  *	.system			= "<system>",
@@ -704,7 +720,7 @@ static inline void ftrace_test_probe_##call(void)			\
 #undef DECLARE_EVENT_CLASS
 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
 _TRACE_PERF_PROTO(call, PARAMS(proto));					\
-static const char print_fmt_##call[] = print;				\
+static char print_fmt_##call[] = print;					\
 static struct ftrace_event_class __used __refdata event_class_##call = { \
 	.system			= TRACE_SYSTEM_STRING,			\
 	.define_fields		= ftrace_define_fields_##call,		\
@@ -733,7 +749,7 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call
 #undef DEFINE_EVENT_PRINT
 #define DEFINE_EVENT_PRINT(template, call, proto, args, print)		\
 									\
-static const char print_fmt_##call[] = print;				\
+static char print_fmt_##call[] = print;					\
 									\
 static struct ftrace_event_call __used event_##call = {			\
 	.class			= &event_class_##template,		\
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 62c6506d663f..c64f8d848aa1 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -123,6 +123,9 @@ enum ftrace_dump_mode ftrace_dump_on_oops;
 /* When set, tracing will stop when a WARN*() is hit */
 int __disable_trace_on_warning;
 
+/* Map of enums to their values */
+static struct trace_enum_map *trace_enum_maps;
+
 static int tracing_set_tracer(struct trace_array *tr, const char *buf);
 
 #define MAX_TRACER_SIZE		100
@@ -3908,6 +3911,34 @@ static const struct file_operations tracing_saved_cmdlines_size_fops = {
 	.write		= tracing_saved_cmdlines_size_write,
 };
 
+static void
+trace_insert_enum_map(struct trace_enum_map **start, struct trace_enum_map **stop)
+{
+	struct trace_enum_map **map;
+	struct trace_enum_map *map_array;
+	int len = stop - start;
+
+	if (len <= 0)
+		return;
+
+	map_array = kmalloc(sizeof(*map_array) * (len + 1), GFP_KERNEL);
+	if (!map_array) {
+		pr_warning("Unable to allocate trace enum mapping\n");
+		return;
+	}
+
+	trace_enum_maps = map_array;
+
+	for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
+		*map_array = **map;
+		map_array++;
+	}
+	memset(map_array, 0, sizeof(*map_array));
+
+	/* Pass in the start of the array (-len) */
+	trace_event_enum_update(&map_array[-len], len);
+}
+
 static ssize_t
 tracing_set_trace_read(struct file *filp, char __user *ubuf,
 		       size_t cnt, loff_t *ppos)
@@ -6542,6 +6573,14 @@ struct dentry *tracing_init_dentry(void)
 	return tr->dir;
 }
 
+extern struct trace_enum_map *__start_ftrace_enum_maps[];
+extern struct trace_enum_map *__stop_ftrace_enum_maps[];
+
+static void __init trace_enum_init(void)
+{
+	trace_insert_enum_map(__start_ftrace_enum_maps, __stop_ftrace_enum_maps);
+}
+
 static __init int tracer_init_debugfs(void)
 {
 	struct dentry *d_tracer;
@@ -6566,6 +6605,8 @@ static __init int tracer_init_debugfs(void)
 	trace_create_file("saved_cmdlines_size", 0644, d_tracer,
 			  NULL, &tracing_saved_cmdlines_size_fops);
 
+	trace_enum_init();
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
 			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
@@ -6888,7 +6929,7 @@ void __init trace_init(void)
 			tracepoint_printk = 0;
 	}
 	tracer_alloc_buffers();
-	trace_event_init();	
+	trace_event_init();
 }
 
 __init static int clear_boot_tracer(void)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index dd8205a35760..8beba964ab26 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1309,8 +1309,10 @@ static inline void init_ftrace_syscalls(void) { }
 
 #ifdef CONFIG_EVENT_TRACING
 void trace_event_init(void);
+void trace_event_enum_update(struct trace_enum_map *map, int len);
 #else
 static inline void __init trace_event_init(void) { }
+static inlin void trace_event_enum_update(struct trace_enum_map *map, int len) { }
 #endif
 
 extern struct trace_iterator *tracepoint_print_iter;
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index db54dda10ccc..6b7fd0bf5d28 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1704,6 +1704,102 @@ __register_event(struct ftrace_event_call *call, struct module *mod)
 	return 0;
 }
 
+static char *enum_replace(char *ptr, struct trace_enum_map *map, int len)
+{
+	int rlen;
+	int elen;
+
+	/* Find the length of the enum value as a string */
+	elen = snprintf(ptr, 0, "%ld", map->enum_value);
+	/* Make sure there's enough room to replace the string with the value */
+	if (len < elen)
+		return NULL;
+
+	snprintf(ptr, elen + 1, "%ld", map->enum_value);
+
+	/* Get the rest of the string of ptr */
+	rlen = strlen(ptr + len);
+	memmove(ptr + elen, ptr + len, rlen);
+	/* Make sure we end the new string */
+	ptr[elen + rlen] = 0;
+
+	return ptr + elen;
+}
+
+static void update_event_printk(struct ftrace_event_call *call,
+				struct trace_enum_map *map)
+{
+	char *ptr;
+	int quote = 0;
+	int len = strlen(map->enum_string);
+
+	for (ptr = call->print_fmt; *ptr; ptr++) {
+		if (*ptr == '\\') {
+			ptr++;
+			/* paranoid */
+			if (!*ptr)
+				break;
+			continue;
+		}
+		if (*ptr == '"') {
+			quote ^= 1;
+			continue;
+		}
+		if (quote)
+			continue;
+		if (isdigit(*ptr)) {
+			/* skip numbers */
+			do {
+				ptr++;
+			} while (isalnum(*ptr) || *ptr == '_');
+			/* we went one too many */
+			ptr--;
+			continue;
+		}
+		if (isalpha(*ptr) || *ptr == '_') {
+			if (strncmp(map->enum_string, ptr, len) == 0 &&
+			    !isalnum(ptr[len]) && ptr[len] != '_') {
+				ptr = enum_replace(ptr, map, len);
+				/* Hmm, enum string smaller than value */
+				if (WARN_ON_ONCE(!ptr))
+					return;
+				continue;
+			}
+			do {
+				ptr++;
+			} while (isalnum(*ptr) || *ptr == '_');
+			/* we went one too many */
+			ptr--;
+			continue;
+		}
+	}
+}
+
+void trace_event_enum_update(struct trace_enum_map *map, int len)
+{
+	struct ftrace_event_call *call, *p;
+	const char *last_system = NULL;
+	int last_i;
+	int i;
+
+	down_write(&trace_event_sem);
+	list_for_each_entry_safe(call, p, &ftrace_events, list) {
+		/* events are usually grouped together with systems */
+		if (!last_system || call->class->system != last_system)
+			last_i = 0;
+
+		for (i = last_i; i < len; i++) {
+			if (call->class->system == map[i].system) {
+				/* Save the first system if need be */
+				if (!last_i)
+					last_i = i;
+				update_event_printk(call, &map[i]);
+			}
+		}
+	}
+	up_write(&trace_event_sem);
+}
+
 static struct ftrace_event_file *
 trace_create_new_event(struct ftrace_event_call *call,
 		       struct trace_array *tr)
-- 
2.1.4

Re: [RFC][PATCH 06/17 v2] tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values

[Namhyung Kim]

Hi Steve,

On Wed, Apr 01, 2015 at 09:56:54PM -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> 
> Several tracepoints use the helper functions __print_symbolic() or
> __print_flags() and pass in enums that do the mapping between the
> binary data stored and the value to print. This works well for reading
> the ASCII trace files, but when the data is read via userspace tools
> such as perf and trace-cmd, the conversion of the binary value to a
> human string format is lost if an enum is used, as userspace does not
> have access to what the ENUM is.
> 
> For example, the tracepoint trace_tlb_flush() has:
> 
>  __print_symbolic(REC->reason,
>     { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" },
>     { TLB_REMOTE_SHOOTDOWN, "remote shootdown" },
>     { TLB_LOCAL_SHOOTDOWN, "local shootdown" },
>     { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" })
> 
> Which maps the enum values to the strings they represent. But perf and
> trace-cmd do no know what value TLB_LOCAL_MM_SHOOTDOWN is, and would
> not be able to map it.
> 
> With TRACE_DEFINE_ENUM(), developers can place these in the event header
> files and ftrace will convert the enums to their values:
> 
> By adding:
> 
>  TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH);
>  TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN);
>  TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN);
>  TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN);
> 
>  $ cat /sys/kernel/debug/tracing/events/tlb/tlb_flush/format
> [...]
>  __print_symbolic(REC->reason,
>     { 0, "flush on task switch" },
>     { 1, "remote shootdown" },
>     { 2, "local shootdown" },
>     { 3, "local mm shootdown" })
> 
> The above is what userspace expects to see, and tools do not need to
> be modified to parse them.
> 
> Cc: Guilherme Cox <cox@computer.org>
> Cc: Tony Luck <tony.luck@gmail.com>
> Cc: Xie XiuQi <xiexiuqi@huawei.com>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>


[SNIP]
> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> index db54dda10ccc..6b7fd0bf5d28 100644
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -1704,6 +1704,102 @@ __register_event(struct ftrace_event_call *call, struct module *mod)
>  	return 0;
>  }
>  
> +static char *enum_replace(char *ptr, struct trace_enum_map *map, int len)
> +{
> +	int rlen;
> +	int elen;
> +
> +	/* Find the length of the enum value as a string */
> +	elen = snprintf(ptr, 0, "%ld", map->enum_value);
> +	/* Make sure there's enough room to replace the string with the value */
> +	if (len < elen)
> +		return NULL;
> +
> +	snprintf(ptr, elen + 1, "%ld", map->enum_value);
> +
> +	/* Get the rest of the string of ptr */
> +	rlen = strlen(ptr + len);
> +	memmove(ptr + elen, ptr + len, rlen);
> +	/* Make sure we end the new string */
> +	ptr[elen + rlen] = 0;
> +
> +	return ptr + elen;
> +}
> +
> +static void update_event_printk(struct ftrace_event_call *call,
> +				struct trace_enum_map *map)
> +{
> +	char *ptr;
> +	int quote = 0;
> +	int len = strlen(map->enum_string);
> +
> +	for (ptr = call->print_fmt; *ptr; ptr++) {
> +		if (*ptr == '\\') {
> +			ptr++;
> +			/* paranoid */
> +			if (!*ptr)
> +				break;
> +			continue;
> +		}
> +		if (*ptr == '"') {
> +			quote ^= 1;
> +			continue;
> +		}
> +		if (quote)
> +			continue;
> +		if (isdigit(*ptr)) {
> +			/* skip numbers */
> +			do {
> +				ptr++;
> +			} while (isalnum(*ptr) || *ptr == '_');
> +			/* we went one too many */

Hmm.. it looks like to skip variable name after a number.  Shouldn't it be 

			do { ptr++; } while (isdigit(*ptr));

?


> +			ptr--;
> +			continue;
> +		}
> +		if (isalpha(*ptr) || *ptr == '_') {
> +			if (strncmp(map->enum_string, ptr, len) == 0 &&
> +			    !isalnum(ptr[len]) && ptr[len] != '_') {
> +				ptr = enum_replace(ptr, map, len);
> +				/* Hmm, enum string smaller than value */
> +				if (WARN_ON_ONCE(!ptr))
> +					return;
> +				continue;

I guess it also needs to decrease the ptr here.


> +			}
> +			do {
> +				ptr++;
> +			} while (isalnum(*ptr) || *ptr == '_');
> +			/* we went one too many */
> +			ptr--;
> +			continue;
> +		}
> +	}
> +}
> +
> +void trace_event_enum_update(struct trace_enum_map *map, int len)
> +{
> +	struct ftrace_event_call *call, *p;
> +	const char *last_system = NULL;
> +	int last_i;
> +	int i;
> +
> +	down_write(&trace_event_sem);
> +	list_for_each_entry_safe(call, p, &ftrace_events, list) {
> +		/* events are usually grouped together with systems */
> +		if (!last_system || call->class->system != last_system)
> +			last_i = 0;

I think it needs to update the last_system here.

Thanks,
Namhyung


> +
> +		for (i = last_i; i < len; i++) {
> +			if (call->class->system == map[i].system) {
> +				/* Save the first system if need be */
> +				if (!last_i)
> +					last_i = i;
> +				update_event_printk(call, &map[i]);
> +			}
> +		}
> +	}
> +	up_write(&trace_event_sem);
> +}
> +
>  static struct ftrace_event_file *
>  trace_create_new_event(struct ftrace_event_call *call,
>  		       struct trace_array *tr)
> -- 
> 2.1.4
> 
> 
> --
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> Please read the FAQ at  http://www.tux.org/lkml/

Re: [RFC][PATCH 06/17 v2] tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values

[Steven Rostedt]

On Thu, 2 Apr 2015 16:47:40 +0900
Namhyung Kim <namhyung@kernel.org> wrote:


> > +static void update_event_printk(struct ftrace_event_call *call,
> > +				struct trace_enum_map *map)
> > +{
> > +	char *ptr;
> > +	int quote = 0;
> > +	int len = strlen(map->enum_string);
> > +
> > +	for (ptr = call->print_fmt; *ptr; ptr++) {
> > +		if (*ptr == '\\') {
> > +			ptr++;
> > +			/* paranoid */
> > +			if (!*ptr)
> > +				break;
> > +			continue;
> > +		}
> > +		if (*ptr == '"') {
> > +			quote ^= 1;
> > +			continue;
> > +		}
> > +		if (quote)
> > +			continue;
> > +		if (isdigit(*ptr)) {
> > +			/* skip numbers */
> > +			do {
> > +				ptr++;
> > +			} while (isalnum(*ptr) || *ptr == '_');
> > +			/* we went one too many */
> 
> Hmm.. it looks like to skip variable name after a number.  Shouldn't it be 
> 
> 			do { ptr++; } while (isdigit(*ptr));
> 
> ?

A variable can not be appended to a number in C. But alpha characters
like 1ULL can be, and they need to be skipped. Hmm, I probably could
remove the check for '_' though.

> 
> 
> > +			ptr--;
> > +			continue;
> > +		}
> > +		if (isalpha(*ptr) || *ptr == '_') {
> > +			if (strncmp(map->enum_string, ptr, len) == 0 &&
> > +			    !isalnum(ptr[len]) && ptr[len] != '_') {
> > +				ptr = enum_replace(ptr, map, len);
> > +				/* Hmm, enum string smaller than value */
> > +				if (WARN_ON_ONCE(!ptr))
> > +					return;
> > +				continue;
> 
> I guess it also needs to decrease the ptr here.

I thought about this when writing it and realized that it just replaced
a variable and two variables can not be bumped against each other.
There must be something in between them, and we can skip whatever that
something is.

I could add a comment about that.

> 
> 
> > +			}
> > +			do {
> > +				ptr++;
> > +			} while (isalnum(*ptr) || *ptr == '_');
> > +			/* we went one too many */
> > +			ptr--;
> > +			continue;
> > +		}
> > +	}
> > +}
> > +
> > +void trace_event_enum_update(struct trace_enum_map *map, int len)
> > +{
> > +	struct ftrace_event_call *call, *p;
> > +	const char *last_system = NULL;
> > +	int last_i;
> > +	int i;
> > +
> > +	down_write(&trace_event_sem);
> > +	list_for_each_entry_safe(call, p, &ftrace_events, list) {
> > +		/* events are usually grouped together with systems */
> > +		if (!last_system || call->class->system != last_system)
> > +			last_i = 0;
> 
> I think it needs to update the last_system here.

Ouch, yeah you're right!

Will fix.

Thanks,

-- Steve

[RFC][PATCH 06/17 v3] tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values

[Steven Rostedt]

Several tracepoints use the helper functions __print_symbolic() or
__print_flags() and pass in enums that do the mapping between the
binary data stored and the value to print. This works well for reading
the ASCII trace files, but when the data is read via userspace tools
such as perf and trace-cmd, the conversion of the binary value to a
human string format is lost if an enum is used, as userspace does not
have access to what the ENUM is.

For example, the tracepoint trace_tlb_flush() has:

 __print_symbolic(REC->reason,
    { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" },
    { TLB_REMOTE_SHOOTDOWN, "remote shootdown" },
    { TLB_LOCAL_SHOOTDOWN, "local shootdown" },
    { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" })

Which maps the enum values to the strings they represent. But perf and
trace-cmd do no know what value TLB_LOCAL_MM_SHOOTDOWN is, and would
not be able to map it.

With TRACE_DEFINE_ENUM(), developers can place these in the event header
files and ftrace will convert the enums to their values:

By adding:

 TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH);
 TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN);
 TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN);
 TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN);

 $ cat /sys/kernel/debug/tracing/events/tlb/tlb_flush/format
[...]
 __print_symbolic(REC->reason,
    { 0, "flush on task switch" },
    { 1, "remote shootdown" },
    { 2, "local shootdown" },
    { 3, "local mm shootdown" })

The above is what userspace expects to see, and tools do not need to
be modified to parse them.

Cc: Guilherme Cox <cox@computer.org>
Cc: Tony Luck <tony.luck@gmail.com>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/asm-generic/vmlinux.lds.h |   5 +-
 include/linux/ftrace_event.h      |   2 +-
 include/linux/tracepoint.h        |   8 +++
 include/trace/ftrace.h            |  22 ++++++--
 kernel/trace/trace.c              |  43 +++++++++++++++-
 kernel/trace/trace.h              |   2 +
 kernel/trace/trace_events.c       | 106 ++++++++++++++++++++++++++++++++++++++
 7 files changed, 182 insertions(+), 6 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index ac78910d7416..f8e8b34dc427 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -124,7 +124,10 @@
 #define FTRACE_EVENTS()	. = ALIGN(8);					\
 			VMLINUX_SYMBOL(__start_ftrace_events) = .;	\
 			*(_ftrace_events)				\
-			VMLINUX_SYMBOL(__stop_ftrace_events) = .;
+			VMLINUX_SYMBOL(__stop_ftrace_events) = .;	\
+			VMLINUX_SYMBOL(__start_ftrace_enum_maps) = .;	\
+			*(_ftrace_enum_map)				\
+			VMLINUX_SYMBOL(__stop_ftrace_enum_maps) = .;
 #else
 #define FTRACE_EVENTS()
 #endif
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 62b8fac7ded5..112cf49d9576 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -285,7 +285,7 @@ struct ftrace_event_call {
 		struct tracepoint	*tp;
 	};
 	struct trace_event	event;
-	const char		*print_fmt;
+	char			*print_fmt;
 	struct event_filter	*filter;
 	void			*mod;
 	void			*data;
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index c72851328ca9..a5f7f3ecafa3 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -36,6 +36,12 @@ struct tracepoint {
 	struct tracepoint_func __rcu *funcs;
 };
 
+struct trace_enum_map {
+	const char		*system;
+	const char		*enum_string;
+	unsigned long		enum_value;
+};
+
 extern int
 tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
 extern int
@@ -87,6 +93,8 @@ extern void syscall_unregfunc(void);
 
 #define PARAMS(args...) args
 
+#define TRACE_DEFINE_ENUM(x)
+
 #endif /* _LINUX_TRACEPOINT_H */
 
 /*
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 2f9b95b6d3fb..37d4b10b111d 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -33,6 +33,19 @@
 
 TRACE_MAKE_SYSTEM_STR();
 
+#undef TRACE_DEFINE_ENUM
+#define TRACE_DEFINE_ENUM(a)				\
+	static struct trace_enum_map __used __initdata	\
+	__##TRACE_SYSTEM##_##a =			\
+	{						\
+		.system = TRACE_SYSTEM_STRING,		\
+		.enum_string = #a,			\
+		.enum_value = a				\
+	};						\
+	static struct trace_enum_map __used		\
+	__attribute__((section("_ftrace_enum_map")))	\
+	*TRACE_SYSTEM##_##a = &__##TRACE_SYSTEM##_##a
+
 /*
  * DECLARE_EVENT_CLASS can be used to add a generic function
  * handlers for events. That is, if all events have the same
@@ -136,6 +149,9 @@ TRACE_MAKE_SYSTEM_STR();
  * The size of an array is also encoded, in the higher 16 bits of <item>.
  */
 
+#undef TRACE_DEFINE_ENUM
+#define TRACE_DEFINE_ENUM(a)
+
 #undef __field
 #define __field(type, item)
 
@@ -553,7 +569,7 @@ static inline notrace int ftrace_get_offsets_##call(			\
  *	.trace			= ftrace_raw_output_<call>, <-- stage 2
  * };
  *
- * static const char print_fmt_<call>[] = <TP_printk>;
+ * static char print_fmt_<call>[] = <TP_printk>;
  *
  * static struct ftrace_event_class __used event_class_<template> = {
  *	.system			= "<system>",
@@ -704,7 +720,7 @@ static inline void ftrace_test_probe_##call(void)			\
 #undef DECLARE_EVENT_CLASS
 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
 _TRACE_PERF_PROTO(call, PARAMS(proto));					\
-static const char print_fmt_##call[] = print;				\
+static char print_fmt_##call[] = print;					\
 static struct ftrace_event_class __used __refdata event_class_##call = { \
 	.system			= TRACE_SYSTEM_STRING,			\
 	.define_fields		= ftrace_define_fields_##call,		\
@@ -733,7 +749,7 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call
 #undef DEFINE_EVENT_PRINT
 #define DEFINE_EVENT_PRINT(template, call, proto, args, print)		\
 									\
-static const char print_fmt_##call[] = print;				\
+static char print_fmt_##call[] = print;					\
 									\
 static struct ftrace_event_call __used event_##call = {			\
 	.class			= &event_class_##template,		\
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 62c6506d663f..c64f8d848aa1 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -123,6 +123,9 @@ enum ftrace_dump_mode ftrace_dump_on_oops;
 /* When set, tracing will stop when a WARN*() is hit */
 int __disable_trace_on_warning;
 
+/* Map of enums to their values */
+static struct trace_enum_map *trace_enum_maps;
+
 static int tracing_set_tracer(struct trace_array *tr, const char *buf);
 
 #define MAX_TRACER_SIZE		100
@@ -3908,6 +3911,34 @@ static const struct file_operations tracing_saved_cmdlines_size_fops = {
 	.write		= tracing_saved_cmdlines_size_write,
 };
 
+static void
+trace_insert_enum_map(struct trace_enum_map **start, struct trace_enum_map **stop)
+{
+	struct trace_enum_map **map;
+	struct trace_enum_map *map_array;
+	int len = stop - start;
+
+	if (len <= 0)
+		return;
+
+	map_array = kmalloc(sizeof(*map_array) * (len + 1), GFP_KERNEL);
+	if (!map_array) {
+		pr_warning("Unable to allocate trace enum mapping\n");
+		return;
+	}
+
+	trace_enum_maps = map_array;
+
+	for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
+		*map_array = **map;
+		map_array++;
+	}
+	memset(map_array, 0, sizeof(*map_array));
+
+	/* Pass in the start of the array (-len) */
+	trace_event_enum_update(&map_array[-len], len);
+}
+
 static ssize_t
 tracing_set_trace_read(struct file *filp, char __user *ubuf,
 		       size_t cnt, loff_t *ppos)
@@ -6542,6 +6573,14 @@ struct dentry *tracing_init_dentry(void)
 	return tr->dir;
 }
 
+extern struct trace_enum_map *__start_ftrace_enum_maps[];
+extern struct trace_enum_map *__stop_ftrace_enum_maps[];
+
+static void __init trace_enum_init(void)
+{
+	trace_insert_enum_map(__start_ftrace_enum_maps, __stop_ftrace_enum_maps);
+}
+
 static __init int tracer_init_debugfs(void)
 {
 	struct dentry *d_tracer;
@@ -6566,6 +6605,8 @@ static __init int tracer_init_debugfs(void)
 	trace_create_file("saved_cmdlines_size", 0644, d_tracer,
 			  NULL, &tracing_saved_cmdlines_size_fops);
 
+	trace_enum_init();
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
 			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
@@ -6888,7 +6929,7 @@ void __init trace_init(void)
 			tracepoint_printk = 0;
 	}
 	tracer_alloc_buffers();
-	trace_event_init();	
+	trace_event_init();
 }
 
 __init static int clear_boot_tracer(void)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index dd8205a35760..8beba964ab26 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1309,8 +1309,10 @@ static inline void init_ftrace_syscalls(void) { }
 
 #ifdef CONFIG_EVENT_TRACING
 void trace_event_init(void);
+void trace_event_enum_update(struct trace_enum_map *map, int len);
 #else
 static inline void __init trace_event_init(void) { }
+static inlin void trace_event_enum_update(struct trace_enum_map *map, int len) { }
 #endif
 
 extern struct trace_iterator *tracepoint_print_iter;
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index db54dda10ccc..cfd6cc328201 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1704,6 +1704,112 @@ __register_event(struct ftrace_event_call *call, struct module *mod)
 	return 0;
 }
 
+static char *enum_replace(char *ptr, struct trace_enum_map *map, int len)
+{
+	int rlen;
+	int elen;
+
+	/* Find the length of the enum value as a string */
+	elen = snprintf(ptr, 0, "%ld", map->enum_value);
+	/* Make sure there's enough room to replace the string with the value */
+	if (len < elen)
+		return NULL;
+
+	snprintf(ptr, elen + 1, "%ld", map->enum_value);
+
+	/* Get the rest of the string of ptr */
+	rlen = strlen(ptr + len);
+	memmove(ptr + elen, ptr + len, rlen);
+	/* Make sure we end the new string */
+	ptr[elen + rlen] = 0;
+
+	return ptr + elen;
+}
+
+static void update_event_printk(struct ftrace_event_call *call,
+				struct trace_enum_map *map)
+{
+	char *ptr;
+	int quote = 0;
+	int len = strlen(map->enum_string);
+
+	for (ptr = call->print_fmt; *ptr; ptr++) {
+		if (*ptr == '\\') {
+			ptr++;
+			/* paranoid */
+			if (!*ptr)
+				break;
+			continue;
+		}
+		if (*ptr == '"') {
+			quote ^= 1;
+			continue;
+		}
+		if (quote)
+			continue;
+		if (isdigit(*ptr)) {
+			/* skip numbers */
+			do {
+				ptr++;
+				/* Check for alpha chars like ULL */
+			} while (isalnum(*ptr));
+			/* we went one too many */
+			ptr--;
+			continue;
+		}
+		if (isalpha(*ptr) || *ptr == '_') {
+			if (strncmp(map->enum_string, ptr, len) == 0 &&
+			    !isalnum(ptr[len]) && ptr[len] != '_') {
+				ptr = enum_replace(ptr, map, len);
+				/* Hmm, enum string smaller than value */
+				if (WARN_ON_ONCE(!ptr))
+					return;
+				/*
+				 * No need to decrement here, as enum_replace()
+				 * returns the pointer to the character passed
+				 * the enum, and two enums can not be placed
+				 * back to back without something in between.
+				 * We can skip that something in between.
+				 */
+				continue;
+			}
+			do {
+				ptr++;
+			} while (isalnum(*ptr) || *ptr == '_');
+			/* we went one too many */
+			ptr--;
+			continue;
+		}
+	}
+}
+
+void trace_event_enum_update(struct trace_enum_map *map, int len)
+{
+	struct ftrace_event_call *call, *p;
+	const char *last_system = NULL;
+	int last_i;
+	int i;
+
+	down_write(&trace_event_sem);
+	list_for_each_entry_safe(call, p, &ftrace_events, list) {
+		/* events are usually grouped together with systems */
+		if (!last_system || call->class->system != last_system) {
+			last_i = 0;
+			last_system = call->class->system;
+		}
+
+		for (i = last_i; i < len; i++) {
+			if (call->class->system == map[i].system) {
+				/* Save the first system if need be */
+				if (!last_i)
+					last_i = i;
+				update_event_printk(call, &map[i]);
+			}
+		}
+	}
+	up_write(&trace_event_sem);
+}
+
 static struct ftrace_event_file *
 trace_create_new_event(struct ftrace_event_call *call,
 		       struct trace_array *tr)
-- 
1.8.3.1

Re: [RFC][PATCH 06/17 v3] tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values

[Steven Rostedt]

I updated the function to handle structures that were saved as well.
Just in case something like REC->my_enum does not get converted.

Also, I found that I never needed to decrement the pointer for those
locations that I did so.

Here's the new function:

static void update_event_printk(struct ftrace_event_call *call,
				struct trace_enum_map *map)
{
	char *ptr;
	int quote = 0;
	int len = strlen(map->enum_string);

	for (ptr = call->print_fmt; *ptr; ptr++) {
		if (*ptr == '\\') {
			ptr++;
			/* paranoid */
			if (!*ptr)
				break;
			continue;
		}
		if (*ptr == '"') {
			quote ^= 1;
			continue;
		}
		if (quote)
			continue;
		if (isdigit(*ptr)) {
			/* skip numbers */
			do {
				ptr++;
				/* Check for alpha chars like ULL */
			} while (isalnum(*ptr));
			/*
			 * A number must have some kind of delimiter after
			 * it, and we can ignore that too.
			 */
			continue;
		}
		if (isalpha(*ptr) || *ptr == '_') {
			if (strncmp(map->enum_string, ptr, len) == 0 &&
			    !isalnum(ptr[len]) && ptr[len] != '_') {
				ptr = enum_replace(ptr, map, len);
				/* Hmm, enum string smaller than value */
				if (WARN_ON_ONCE(!ptr))
					return;
				/*
				 * No need to decrement here, as enum_replace()
				 * returns the pointer to the character passed
				 * the enum, and two enums can not be placed
				 * back to back without something in between.
				 * We can skip that something in between.
				 */
				continue;
			}
		skip_more:
			do {
				ptr++;
			} while (isalnum(*ptr) || *ptr == '_');
			/*
			 * If what comes after this variable is a '.' or
			 * '->' then we can continue to ignore that string.
			 */
			if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
				ptr += *ptr == '.' ? 1 : 2;
				goto skip_more;
			}
			/*
			 * Once again, we can skip the delimiter that came
			 * after the string.
			 */
			continue;
		}
	}
}

[RFC][PATCH 07/17 v2] tracing: Allow for modules to export their trace enums as well

[Steven Rostedt]

[-- Attachment #1: 0007-tracing-Allow-for-modules-to-export-their-trace-enum.patch --]
[-- Type: text/plain, Size: 7335 bytes --]

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

Update the infrastructure such that modules that declare TRACE_DEFINE_ENUM()
will have those enums shown in the enum_map files in the tracing directory.

Link: http://lkml.kernel.org/r/87vbhjp74q.fsf@rustcorp.com.au

Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/module.h      |   2 +
 kernel/module.c             |   3 +
 kernel/trace/trace.c        | 149 +++++++++++++++++++++++++++++++++++++++++---
 kernel/trace/trace_events.c |   2 +-
 4 files changed, 145 insertions(+), 11 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 42999fe2dbd0..53dc41dd5c62 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -338,6 +338,8 @@ struct module {
 #ifdef CONFIG_EVENT_TRACING
 	struct ftrace_event_call **trace_events;
 	unsigned int num_trace_events;
+	struct trace_enum_map **trace_enums;
+	unsigned int num_trace_enums;
 #endif
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 	unsigned int num_ftrace_callsites;
diff --git a/kernel/module.c b/kernel/module.c
index b3d634ed06c9..d8f8ab271c2b 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2753,6 +2753,9 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 	mod->trace_events = section_objs(info, "_ftrace_events",
 					 sizeof(*mod->trace_events),
 					 &mod->num_trace_events);
+	mod->trace_enums = section_objs(info, "_ftrace_enum_map",
+					sizeof(*mod->trace_enums),
+					&mod->num_trace_enums);
 #endif
 #ifdef CONFIG_TRACING
 	mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c64f8d848aa1..c9a714a42b7b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -124,7 +124,36 @@ enum ftrace_dump_mode ftrace_dump_on_oops;
 int __disable_trace_on_warning;
 
 /* Map of enums to their values */
-static struct trace_enum_map *trace_enum_maps;
+struct trace_enum_map_head {
+	struct module			*mod;
+	unsigned long			length;
+};
+
+union trace_enum_map_item;
+
+struct trace_enum_map_tail {
+	/*
+	 * "end" is first and points to NULL as it must be different
+	 * than "mod" or "enum_string"
+	 */
+	const char			*end;	/* points to NULL */
+	union trace_enum_map_item	*next;
+};
+
+/*
+ * The trace_enum_maps are saved in an array with two extra elements,
+ * one at the beginning, and one at the end. The beginning item contains
+ * the count of the saved maps (head.length), and the module they
+ * belong to if not built in (head.mod). The ending item contains a
+ * pointer to the next array of saved enum_map items.
+ */
+union trace_enum_map_item {
+	struct trace_enum_map		map;
+	struct trace_enum_map_head	head;
+	struct trace_enum_map_tail	tail;
+};
+
+static union trace_enum_map_item *trace_enum_maps;
 
 static int tracing_set_tracer(struct trace_array *tr, const char *buf);
 
@@ -3911,32 +3940,62 @@ static const struct file_operations tracing_saved_cmdlines_size_fops = {
 	.write		= tracing_saved_cmdlines_size_write,
 };
 
-static void
-trace_insert_enum_map(struct trace_enum_map **start, struct trace_enum_map **stop)
+static inline union trace_enum_map_item *
+trace_enum_jmp_to_tail(union trace_enum_map_item *ptr)
+{
+	/* Return tail of array given the head */
+	return ptr + ptr->head.length + 1;
+}
+
+static void trace_insert_enum_map(struct module *mod,
+				  struct trace_enum_map **start, int len)
 {
+	struct trace_enum_map **stop;
 	struct trace_enum_map **map;
-	struct trace_enum_map *map_array;
-	int len = stop - start;
+	union trace_enum_map_item *map_array;
+	union trace_enum_map_item *ptr;
 
 	if (len <= 0)
 		return;
 
-	map_array = kmalloc(sizeof(*map_array) * (len + 1), GFP_KERNEL);
+	stop = start + len;
+
+	/*
+	 * The trace_enum_maps contains the map plus a head and tail item,
+	 * where the head holds the module and length of array, and the
+	 * tail holds a pointer to the next list.
+	 */
+	map_array = kmalloc(sizeof(*map_array) * (len + 2), GFP_KERNEL);
 	if (!map_array) {
 		pr_warning("Unable to allocate trace enum mapping\n");
 		return;
 	}
 
-	trace_enum_maps = map_array;
+	if (!trace_enum_maps)
+		trace_enum_maps = map_array;
+	else {
+		ptr = trace_enum_maps;
+		for (;;) {
+			ptr = trace_enum_jmp_to_tail(ptr);
+			if (!ptr->tail.next)
+				break;
+			ptr = ptr->tail.next;
+
+		}
+		ptr->tail.next = map_array;
+	}
+	map_array->head.mod = mod;
+	map_array->head.length = len;
+	map_array++;
 
 	for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
-		*map_array = **map;
+		map_array->map = **map;
 		map_array++;
 	}
 	memset(map_array, 0, sizeof(*map_array));
 
 	/* Pass in the start of the array (-len) */
-	trace_event_enum_update(&map_array[-len], len);
+	trace_event_enum_update(&map_array[-len].map, len);
 }
 
 static ssize_t
@@ -6578,9 +6637,75 @@ extern struct trace_enum_map *__stop_ftrace_enum_maps[];
 
 static void __init trace_enum_init(void)
 {
-	trace_insert_enum_map(__start_ftrace_enum_maps, __stop_ftrace_enum_maps);
+	int len;
+
+	len = __stop_ftrace_enum_maps - __start_ftrace_enum_maps;
+	trace_insert_enum_map(NULL, __start_ftrace_enum_maps, len);
+}
+
+#ifdef CONFIG_MODULES
+static void trace_module_add_enums(struct module *mod)
+{
+	if (!mod->num_trace_enums)
+		return;
+
+	/*
+	 * Modules with bad taint do not have events created, do
+	 * not bother with enums either.
+	 */
+	if (trace_module_has_bad_taint(mod))
+		return;
+
+	trace_insert_enum_map(mod, mod->trace_enums, mod->num_trace_enums);
+}
+
+static void trace_module_remove_enums(struct module *mod)
+{
+	union trace_enum_map_item *map;
+	union trace_enum_map_item **last = &trace_enum_maps;
+
+	if (!mod->num_trace_enums)
+		return;
+
+	map = trace_enum_maps;
+
+	while (map) {
+		if (map->head.mod == mod)
+			break;
+		map = trace_enum_jmp_to_tail(map);
+		last = &map->tail.next;
+		map = map->tail.next;
+	}
+	if (!map)
+		return;
+
+	*last = trace_enum_jmp_to_tail(map)->tail.next;
+	kfree(map);
+}
+
+static int trace_module_notify(struct notifier_block *self,
+			       unsigned long val, void *data)
+{
+	struct module *mod = data;
+
+	switch (val) {
+	case MODULE_STATE_COMING:
+		trace_module_add_enums(mod);
+		break;
+	case MODULE_STATE_GOING:
+		trace_module_remove_enums(mod);
+		break;
+	}
+
+	return 0;
 }
 
+static struct notifier_block trace_module_nb = {
+	.notifier_call = trace_module_notify,
+	.priority = 0,
+};
+#endif
+
 static __init int tracer_init_debugfs(void)
 {
 	struct dentry *d_tracer;
@@ -6607,6 +6732,10 @@ static __init int tracer_init_debugfs(void)
 
 	trace_enum_init();
 
+#ifdef CONFIG_MODULES
+	register_module_notifier(&trace_module_nb);
+#endif
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
 			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 6b7fd0bf5d28..d5571d88d48d 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2011,7 +2011,7 @@ static int trace_module_notify(struct notifier_block *self,
 
 static struct notifier_block trace_module_nb = {
 	.notifier_call = trace_module_notify,
-	.priority = 0,
+	.priority = 1, /* higher than trace.c module notify */
 };
 #endif /* CONFIG_MODULES */
 
-- 
2.1.4

[RFC][PATCH 08/17 v2] tracing/samples: Update the trace-event-sample.h with TRACE_DEFINE_ENUM()

[Steven Rostedt]

[-- Attachment #1: 0008-tracing-samples-Update-the-trace-event-sample.h-with.patch --]
[-- Type: text/plain, Size: 3443 bytes --]

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

Document the use of TRACE_DEFINE_ENUM() by adding enums to the
trace-event-sample.h and using this macro to convert them in the format
files.

Also update the comments and sho the use of __print_symbolic() and
__print_flags() as well as adding comments abount __print_array().

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 samples/trace_events/trace-events-sample.h | 64 +++++++++++++++++++++++++++++-
 1 file changed, 63 insertions(+), 1 deletion(-)

diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 19405f18cc8a..8965d1bb8811 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -198,8 +198,30 @@ static inline int __length_of(const int *list)
 		;
 	return i;
 }
+
+enum {
+	TRACE_SAMPLE_FOO = 2,
+	TRACE_SAMPLE_BAR = 4,
+	TRACE_SAMPLE_ZOO = 8,
+};
 #endif
 
+/*
+ * If enums are used in the TP_printk(), their names will be shown in
+ * format files and not their values. This can cause problems with user
+ * space programs that parse the format files to know how to translate
+ * the raw binary trace output into human readable text.
+ *
+ * To help out user space programs, any enum that is used in the TP_printk()
+ * should be defined by TRACE_DEFINE_ENUM() macro. All that is needed to
+ * be done is to add this macro with the enum within it in the trace
+ * header file, and it will be converted in the output.
+ */
+
+TRACE_DEFINE_ENUM(TRACE_SAMPLE_FOO);
+TRACE_DEFINE_ENUM(TRACE_SAMPLE_BAR);
+TRACE_DEFINE_ENUM(TRACE_SAMPLE_ZOO);
+
 TRACE_EVENT(foo_bar,
 
 	TP_PROTO(const char *foo, int bar, const int *lst,
@@ -224,7 +246,47 @@ TRACE_EVENT(foo_bar,
 		__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
 	),
 
-	TP_printk("foo %s %d %s %s (%s)", __entry->foo, __entry->bar,
+	TP_printk("foo %s %d %s %s %s %s (%s)", __entry->foo, __entry->bar,
+
+/*
+ * Notice here the use of some helper functions. This includes:
+ *
+ *  __print_symbolic( variable, { value, "string" }, ... ),
+ *
+ *    The variable is tested against each value of the { } pair. If
+ *    the variable matches one of the values, then it will print the
+ *    string in that pair. If non are matched, it returns a string
+ *    version of the number (if __entry->bar == 7 then "7" is returned).
+ */
+		  __print_symbolic(__entry->bar,
+				   { 0, "zero" },
+				   { TRACE_SAMPLE_FOO, "TWO" },
+				   { TRACE_SAMPLE_BAR, "FOUR" },
+				   { TRACE_SAMPLE_ZOO, "EIGHT" },
+				   { 10, "TEN" }
+			  ),
+
+/*
+ *  __print_flags( variable, "delim", { value, "flag" }, ... ),
+ *
+ *    This is similar to __print_symbolic, except that it tests the bits
+ *    of the value. If ((FLAG & variable) == FLAG) then the string is
+ *    printed. If more than one flag matches, then each one that does is
+ *    also printed with delim in between them.
+ *    If not all bits are accounted for, then the not found bits will be
+ *    added in hex format: 0x506 will show BIT2|BIT4|0x500
+ */
+		  __print_flags(__entry->bar, "|",
+				{ 1, "BIT1" },
+				{ 2, "BIT2" },
+				{ 4, "BIT3" },
+				{ 8, "BIT4" }
+			  ),
+/*
+ *  __print_array( array, len, element_size )
+ *
+ *    This prints out the array that is defined by __array in a nice format.
+ */
 		  __print_array(__get_dynamic_array(list),
 				__get_dynamic_array_len(list),
 				sizeof(int)),
-- 
2.1.4

[RFC][PATCH 09/17 v2] tracing: Show the mapped enums in enum_map file

[Steven Rostedt]

[-- Attachment #1: 0009-tracing-Show-the-mapped-enums-in-enum_map-file.patch --]
[-- Type: text/plain, Size: 4568 bytes --]

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

Add a enum_map file in the tracing directory to see what enums have been
saved to convert in the print fmt files.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 107 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c9a714a42b7b..f2e63d0bf45e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -123,7 +123,7 @@ enum ftrace_dump_mode ftrace_dump_on_oops;
 /* When set, tracing will stop when a WARN*() is hit */
 int __disable_trace_on_warning;
 
-/* Map of enums to their values */
+/* Map of enums to their values, for "enum_map" file */
 struct trace_enum_map_head {
 	struct module			*mod;
 	unsigned long			length;
@@ -136,10 +136,12 @@ struct trace_enum_map_tail {
 	 * "end" is first and points to NULL as it must be different
 	 * than "mod" or "enum_string"
 	 */
-	const char			*end;	/* points to NULL */
 	union trace_enum_map_item	*next;
+	const char			*end;	/* points to NULL */
 };
 
+static DEFINE_MUTEX(trace_enum_mutex);
+
 /*
  * The trace_enum_maps are saved in an array with two extra elements,
  * one at the beginning, and one at the end. The beginning item contains
@@ -3940,6 +3942,97 @@ static const struct file_operations tracing_saved_cmdlines_size_fops = {
 	.write		= tracing_saved_cmdlines_size_write,
 };
 
+static union trace_enum_map_item *
+update_enum_map(union trace_enum_map_item *ptr)
+{
+	if (!ptr->map.enum_string) {
+		if (ptr->tail.next) {
+			ptr = ptr->tail.next;
+			/* Set ptr to the next real item (skip head) */
+			ptr++;
+		} else
+			return NULL;
+	}
+	return ptr;
+}
+
+static void *enum_map_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	union trace_enum_map_item *ptr = v;
+
+	/*
+	 * Paranoid! If ptr points to end, we don't want to increment past it.
+	 * This really should never happen.
+	 */
+	ptr = update_enum_map(ptr);
+	if (WARN_ON_ONCE(!ptr))
+		return NULL;
+
+	ptr++;
+
+	(*pos)++;
+
+	ptr = update_enum_map(ptr);
+
+	return ptr;
+}
+
+static void *enum_map_start(struct seq_file *m, loff_t *pos)
+{
+	union trace_enum_map_item *v;
+	loff_t l = 0;
+
+	mutex_lock(&trace_enum_mutex);
+
+	v = trace_enum_maps;
+	if (v)
+		v++;
+
+	while (v && l < *pos) {
+		v = enum_map_next(m, v, &l);
+	}
+
+	return v;
+}
+
+static void enum_map_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&trace_enum_mutex);
+}
+
+static int enum_map_show(struct seq_file *m, void *v)
+{
+	union trace_enum_map_item *ptr = v;
+
+	seq_printf(m, "%s %ld (%s)\n",
+		   ptr->map.enum_string, ptr->map.enum_value,
+		   ptr->map.system);
+
+	return 0;
+}
+
+static const struct seq_operations tracing_enum_map_seq_ops = {
+	.start		= enum_map_start,
+	.next		= enum_map_next,
+	.stop		= enum_map_stop,
+	.show		= enum_map_show,
+};
+
+static int tracing_enum_map_open(struct inode *inode, struct file *filp)
+{
+	if (tracing_disabled)
+		return -ENODEV;
+
+	return seq_open(filp, &tracing_enum_map_seq_ops);
+}
+
+static const struct file_operations tracing_enum_map_fops = {
+	.open		= tracing_enum_map_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
 static inline union trace_enum_map_item *
 trace_enum_jmp_to_tail(union trace_enum_map_item *ptr)
 {
@@ -3971,6 +4064,8 @@ static void trace_insert_enum_map(struct module *mod,
 		return;
 	}
 
+	mutex_lock(&trace_enum_mutex);
+
 	if (!trace_enum_maps)
 		trace_enum_maps = map_array;
 	else {
@@ -3996,6 +4091,8 @@ static void trace_insert_enum_map(struct module *mod,
 
 	/* Pass in the start of the array (-len) */
 	trace_event_enum_update(&map_array[-len].map, len);
+
+	mutex_unlock(&trace_enum_mutex);
 }
 
 static ssize_t
@@ -6667,6 +6764,8 @@ static void trace_module_remove_enums(struct module *mod)
 	if (!mod->num_trace_enums)
 		return;
 
+	mutex_lock(&trace_enum_mutex);
+
 	map = trace_enum_maps;
 
 	while (map) {
@@ -6677,10 +6776,12 @@ static void trace_module_remove_enums(struct module *mod)
 		map = map->tail.next;
 	}
 	if (!map)
-		return;
+		goto out;
 
 	*last = trace_enum_jmp_to_tail(map)->tail.next;
 	kfree(map);
+ out:
+	mutex_unlock(&trace_enum_mutex);
 }
 
 static int trace_module_notify(struct notifier_block *self,
@@ -6732,6 +6833,9 @@ static __init int tracer_init_debugfs(void)
 
 	trace_enum_init();
 
+	trace_create_file("enum_map", 0444, d_tracer,
+			  NULL, &tracing_enum_map_fops);
+
 #ifdef CONFIG_MODULES
 	register_module_notifier(&trace_module_nb);
 #endif
-- 
2.1.4

Re: [RFC][PATCH 09/17 v2] tracing: Show the mapped enums in enum_map file

[Steven Rostedt]

On Wed, 01 Apr 2015 21:56:57 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> 
> Add a enum_map file in the tracing directory to see what enums have been
> saved to convert in the print fmt files.

Hmm, I'm thinking of dropping this patch, and adding it later with a
config option. This way, when it is not enabled, the data used for
conversion can be freed. I rather have that then have this stuck as an
API.

Adding it with a config option that states that it will waste memory
lets the distros decide if they want the extra footprint or not.

-- Steve

[RFC][PATCH 10/17 v2] x86/tlb/trace: Export enums in used by tlb_flush tracepoint

[Steven Rostedt]

[-- Attachment #1: 0010-x86-tlb-trace-Export-enums-in-used-by-tlb_flush-trac.patch --]
[-- Type: text/plain, Size: 1645 bytes --]

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

Have the enums used in __print_symbolic() by the trace_tlb_flush()
tracepoint exported to userpace such that they can be parsed by
userspace tools.

Cc: Dave Hansen <dave@sr71.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/tlb.h | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/include/trace/events/tlb.h b/include/trace/events/tlb.h
index 0e7635765153..4250f364a6ca 100644
--- a/include/trace/events/tlb.h
+++ b/include/trace/events/tlb.h
@@ -7,11 +7,31 @@
 #include <linux/mm_types.h>
 #include <linux/tracepoint.h>
 
-#define TLB_FLUSH_REASON	\
-	{ TLB_FLUSH_ON_TASK_SWITCH,	"flush on task switch" },	\
-	{ TLB_REMOTE_SHOOTDOWN,		"remote shootdown" },		\
-	{ TLB_LOCAL_SHOOTDOWN,		"local shootdown" },		\
-	{ TLB_LOCAL_MM_SHOOTDOWN,	"local mm shootdown" }
+#define TLB_FLUSH_REASON						\
+	EM(  TLB_FLUSH_ON_TASK_SWITCH,	"flush on task switch" )	\
+	EM(  TLB_REMOTE_SHOOTDOWN,	"remote shootdown" )		\
+	EM(  TLB_LOCAL_SHOOTDOWN,	"local shootdown" )		\
+	EMe( TLB_LOCAL_MM_SHOOTDOWN,	"local mm shootdown" )
+
+/*
+ * First define the enums in TLB_FLUSH_REASON to be exported to userspace
+ * via TRACE_DEFINE_ENUM().
+ */
+#undef EM
+#undef EMe
+#define EM(a,b)		TRACE_DEFINE_ENUM(a);
+#define EMe(a,b)	TRACE_DEFINE_ENUM(a);
+
+TLB_FLUSH_REASON
+
+/*
+ * Now redefine the EM() and EMe() macros to map the enums to the strings
+ * that will be printed in the output.
+ */
+#undef EM
+#undef EMe
+#define EM(a,b)		{ a, b },
+#define EMe(a,b)	{ a, b }
 
 TRACE_EVENT_CONDITION(tlb_flush,
 
-- 
2.1.4

[RFC][PATCH 11/17 v2] net/9p/tracing: Export enums in tracepoints to userspace

[Steven Rostedt]

[-- Attachment #1: 0011-net-9p-tracing-Export-enums-in-tracepoints-to-usersp.patch --]
[-- Type: text/plain, Size: 6698 bytes --]

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

The tracepoints in the 9p code use a lot of enums for the __print_symbolic()
function. These enums are shown in the tracepoint format files, and user
space tools such as trace-cmd does not have the information to parse it.
Add helper macros to export the enums with TRACE_DEFINE_ENUM().

Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/9p.h | 157 ++++++++++++++++++++++++++--------------------
 1 file changed, 88 insertions(+), 69 deletions(-)

diff --git a/include/trace/events/9p.h b/include/trace/events/9p.h
index a0666362c111..633ee9ee9778 100644
--- a/include/trace/events/9p.h
+++ b/include/trace/events/9p.h
@@ -6,76 +6,95 @@
 
 #include <linux/tracepoint.h>
 
+#define P9_MSG_T							\
+		EM( P9_TLERROR,		"P9_TLERROR" )			\
+		EM( P9_RLERROR,		"P9_RLERROR" )			\
+		EM( P9_TSTATFS,		"P9_TSTATFS" )			\
+		EM( P9_RSTATFS,		"P9_RSTATFS" )			\
+		EM( P9_TLOPEN,		"P9_TLOPEN" )			\
+		EM( P9_RLOPEN,		"P9_RLOPEN" )			\
+		EM( P9_TLCREATE,	"P9_TLCREATE" )			\
+		EM( P9_RLCREATE,	"P9_RLCREATE" )			\
+		EM( P9_TSYMLINK,	"P9_TSYMLINK" )			\
+		EM( P9_RSYMLINK,	"P9_RSYMLINK" )			\
+		EM( P9_TMKNOD,		"P9_TMKNOD" )			\
+		EM( P9_RMKNOD,		"P9_RMKNOD" )			\
+		EM( P9_TRENAME,		"P9_TRENAME" )			\
+		EM( P9_RRENAME,		"P9_RRENAME" )			\
+		EM( P9_TREADLINK,	"P9_TREADLINK" )		\
+		EM( P9_RREADLINK,	"P9_RREADLINK" )		\
+		EM( P9_TGETATTR,	"P9_TGETATTR" )			\
+		EM( P9_RGETATTR,	"P9_RGETATTR" )			\
+		EM( P9_TSETATTR,	"P9_TSETATTR" )			\
+		EM( P9_RSETATTR,	"P9_RSETATTR" )			\
+		EM( P9_TXATTRWALK,	"P9_TXATTRWALK" )		\
+		EM( P9_RXATTRWALK,	"P9_RXATTRWALK" )		\
+		EM( P9_TXATTRCREATE,	"P9_TXATTRCREATE" )		\
+		EM( P9_RXATTRCREATE,	"P9_RXATTRCREATE" )		\
+		EM( P9_TREADDIR,	"P9_TREADDIR" )			\
+		EM( P9_RREADDIR,	"P9_RREADDIR" )			\
+		EM( P9_TFSYNC,		"P9_TFSYNC" )			\
+		EM( P9_RFSYNC,		"P9_RFSYNC" )			\
+		EM( P9_TLOCK,		"P9_TLOCK" )			\
+		EM( P9_RLOCK,		"P9_RLOCK" )			\
+		EM( P9_TGETLOCK,	"P9_TGETLOCK" )			\
+		EM( P9_RGETLOCK,	"P9_RGETLOCK" )			\
+		EM( P9_TLINK,		"P9_TLINK" )			\
+		EM( P9_RLINK,		"P9_RLINK" )			\
+		EM( P9_TMKDIR,		"P9_TMKDIR" )			\
+		EM( P9_RMKDIR,		"P9_RMKDIR" )			\
+		EM( P9_TRENAMEAT,	"P9_TRENAMEAT" )		\
+		EM( P9_RRENAMEAT,	"P9_RRENAMEAT" )		\
+		EM( P9_TUNLINKAT,	"P9_TUNLINKAT" )		\
+		EM( P9_RUNLINKAT,	"P9_RUNLINKAT" )		\
+		EM( P9_TVERSION,	"P9_TVERSION" )			\
+		EM( P9_RVERSION,	"P9_RVERSION" )			\
+		EM( P9_TAUTH,		"P9_TAUTH" )			\
+		EM( P9_RAUTH,		"P9_RAUTH" )			\
+		EM( P9_TATTACH,		"P9_TATTACH" )			\
+		EM( P9_RATTACH,		"P9_RATTACH" )			\
+		EM( P9_TERROR,		"P9_TERROR" )			\
+		EM( P9_RERROR,		"P9_RERROR" )			\
+		EM( P9_TFLUSH,		"P9_TFLUSH" )			\
+		EM( P9_RFLUSH,		"P9_RFLUSH" )			\
+		EM( P9_TWALK,		"P9_TWALK" )			\
+		EM( P9_RWALK,		"P9_RWALK" )			\
+		EM( P9_TOPEN,		"P9_TOPEN" )			\
+		EM( P9_ROPEN,		"P9_ROPEN" )			\
+		EM( P9_TCREATE,		"P9_TCREATE" )			\
+		EM( P9_RCREATE,		"P9_RCREATE" )			\
+		EM( P9_TREAD,		"P9_TREAD" )			\
+		EM( P9_RREAD,		"P9_RREAD" )			\
+		EM( P9_TWRITE,		"P9_TWRITE" )			\
+		EM( P9_RWRITE,		"P9_RWRITE" )			\
+		EM( P9_TCLUNK,		"P9_TCLUNK" )			\
+		EM( P9_RCLUNK,		"P9_RCLUNK" )			\
+		EM( P9_TREMOVE,		"P9_TREMOVE" )			\
+		EM( P9_RREMOVE,		"P9_RREMOVE" )			\
+		EM( P9_TSTAT,		"P9_TSTAT" )			\
+		EM( P9_RSTAT,		"P9_RSTAT" )			\
+		EM( P9_TWSTAT,		"P9_TWSTAT" )			\
+		EMe(P9_RWSTAT,		"P9_RWSTAT" )
+
+/* Define EM() to export the enums to userspace via TRACE_DEFINE_ENUM() */
+#undef EM
+#undef EMe
+#define EM(a, b)	TRACE_DEFINE_ENUM(a);
+#define EMe(a, b)	TRACE_DEFINE_ENUM(a);
+
+P9_MSG_T
+
+/*
+ * Now redefine the EM() and EMe() macros to map the enums to the strings
+ * that will be printed in the output.
+ */
+#undef EM
+#undef EMe
+#define EM(a, b)	{ a, b },
+#define EMe(a, b)	{ a, b }
+
 #define show_9p_op(type)						\
-	__print_symbolic(type,						\
-			 { P9_TLERROR,		"P9_TLERROR" },		\
-			 { P9_RLERROR,		"P9_RLERROR" },		\
-			 { P9_TSTATFS,		"P9_TSTATFS" },		\
-			 { P9_RSTATFS,		"P9_RSTATFS" },		\
-			 { P9_TLOPEN,		"P9_TLOPEN" },		\
-			 { P9_RLOPEN,		"P9_RLOPEN" },		\
-			 { P9_TLCREATE,		"P9_TLCREATE" },	\
-			 { P9_RLCREATE,		"P9_RLCREATE" },	\
-			 { P9_TSYMLINK,		"P9_TSYMLINK" },	\
-			 { P9_RSYMLINK,		"P9_RSYMLINK" },	\
-			 { P9_TMKNOD,		"P9_TMKNOD" },		\
-			 { P9_RMKNOD,		"P9_RMKNOD" },		\
-			 { P9_TRENAME,		"P9_TRENAME" },		\
-			 { P9_RRENAME,		"P9_RRENAME" },		\
-			 { P9_TREADLINK,	"P9_TREADLINK" },	\
-			 { P9_RREADLINK,	"P9_RREADLINK" },	\
-			 { P9_TGETATTR,		"P9_TGETATTR" },	\
-			 { P9_RGETATTR,		"P9_RGETATTR" },	\
-			 { P9_TSETATTR,		"P9_TSETATTR" },	\
-			 { P9_RSETATTR,		"P9_RSETATTR" },	\
-			 { P9_TXATTRWALK,	"P9_TXATTRWALK" },	\
-			 { P9_RXATTRWALK,	"P9_RXATTRWALK" },	\
-			 { P9_TXATTRCREATE,	"P9_TXATTRCREATE" },	\
-			 { P9_RXATTRCREATE,	"P9_RXATTRCREATE" },	\
-			 { P9_TREADDIR,		"P9_TREADDIR" },	\
-			 { P9_RREADDIR,		"P9_RREADDIR" },	\
-			 { P9_TFSYNC,		"P9_TFSYNC" },		\
-			 { P9_RFSYNC,		"P9_RFSYNC" },		\
-			 { P9_TLOCK,		"P9_TLOCK" },		\
-			 { P9_RLOCK,		"P9_RLOCK" },		\
-			 { P9_TGETLOCK,		"P9_TGETLOCK" },	\
-			 { P9_RGETLOCK,		"P9_RGETLOCK" },	\
-			 { P9_TLINK,		"P9_TLINK" },		\
-			 { P9_RLINK,		"P9_RLINK" },		\
-			 { P9_TMKDIR,		"P9_TMKDIR" },		\
-			 { P9_RMKDIR,		"P9_RMKDIR" },		\
-			 { P9_TRENAMEAT,	"P9_TRENAMEAT" },	\
-			 { P9_RRENAMEAT,	"P9_RRENAMEAT" },	\
-			 { P9_TUNLINKAT,	"P9_TUNLINKAT" },	\
-			 { P9_RUNLINKAT,	"P9_RUNLINKAT" },	\
-			 { P9_TVERSION,		"P9_TVERSION" },	\
-			 { P9_RVERSION,		"P9_RVERSION" },	\
-			 { P9_TAUTH,		"P9_TAUTH" },		\
-			 { P9_RAUTH,		"P9_RAUTH" },		\
-			 { P9_TATTACH,		"P9_TATTACH" },		\
-			 { P9_RATTACH,		"P9_RATTACH" },		\
-			 { P9_TERROR,		"P9_TERROR" },		\
-			 { P9_RERROR,		"P9_RERROR" },		\
-			 { P9_TFLUSH,		"P9_TFLUSH" },		\
-			 { P9_RFLUSH,		"P9_RFLUSH" },		\
-			 { P9_TWALK,		"P9_TWALK" },		\
-			 { P9_RWALK,		"P9_RWALK" },		\
-			 { P9_TOPEN,		"P9_TOPEN" },		\
-			 { P9_ROPEN,		"P9_ROPEN" },		\
-			 { P9_TCREATE,		"P9_TCREATE" },		\
-			 { P9_RCREATE,		"P9_RCREATE" },		\
-			 { P9_TREAD,		"P9_TREAD" },		\
-			 { P9_RREAD,		"P9_RREAD" },		\
-			 { P9_TWRITE,		"P9_TWRITE" },		\
-			 { P9_RWRITE,		"P9_RWRITE" },		\
-			 { P9_TCLUNK,		"P9_TCLUNK" },		\
-			 { P9_RCLUNK,		"P9_RCLUNK" },		\
-			 { P9_TREMOVE,		"P9_TREMOVE" },		\
-			 { P9_RREMOVE,		"P9_RREMOVE" },		\
-			 { P9_TSTAT,		"P9_TSTAT" },		\
-			 { P9_RSTAT,		"P9_RSTAT" },		\
-			 { P9_TWSTAT,		"P9_TWSTAT" },		\
-			 { P9_RWSTAT,		"P9_RWSTAT" })
+	__print_symbolic(type, P9_MSG_T)
 
 TRACE_EVENT(9p_client_req,
 	    TP_PROTO(struct p9_client *clnt, int8_t type, int tag),
-- 
2.1.4

[RFC][PATCH 12/17 v2] f2fs: Export the enums in the tracepoints to userspace

[Steven Rostedt]

[-- Attachment #1: 0012-f2fs-Export-the-enums-in-the-tracepoints-to-userspac.patch --]
[-- Type: text/plain, Size: 2099 bytes --]

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

The tracepoints that use __print_symbolic() use enums as the value
to convert to strings. Unfortunately, the format files for these
tracepoints show the enum name and not their value. This causes some
userspace tools not to know how to convert __print_symbolic() to
their strings.

Add TRACE_DEFINE_ENUM() macros to export the enums used to userspace
to let those tools know what those enum values are.

Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Pankaj Kumar <pankaj.km@samsung.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/f2fs.h | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index 5422dbfaf97d..36f4536b6149 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -9,6 +9,36 @@
 #define show_dev(entry)		MAJOR(entry->dev), MINOR(entry->dev)
 #define show_dev_ino(entry)	show_dev(entry), (unsigned long)entry->ino
 
+TRACE_DEFINE_ENUM(NODE);
+TRACE_DEFINE_ENUM(DATA);
+TRACE_DEFINE_ENUM(META);
+TRACE_DEFINE_ENUM(META_FLUSH);
+TRACE_DEFINE_ENUM(CURSEG_HOT_DATA);
+TRACE_DEFINE_ENUM(CURSEG_WARM_DATA);
+TRACE_DEFINE_ENUM(CURSEG_COLD_DATA);
+TRACE_DEFINE_ENUM(CURSEG_HOT_NODE);
+TRACE_DEFINE_ENUM(CURSEG_WARM_NODE);
+TRACE_DEFINE_ENUM(CURSEG_COLD_NODE);
+TRACE_DEFINE_ENUM(NO_CHECK_TYPE);
+TRACE_DEFINE_ENUM(GC_GREEDY);
+TRACE_DEFINE_ENUM(GC_CB);
+TRACE_DEFINE_ENUM(FG_GC);
+TRACE_DEFINE_ENUM(BG_GC);
+TRACE_DEFINE_ENUM(LFS);
+TRACE_DEFINE_ENUM(SSR);
+TRACE_DEFINE_ENUM(__REQ_RAHEAD);
+TRACE_DEFINE_ENUM(__REQ_WRITE);
+TRACE_DEFINE_ENUM(__REQ_SYNC);
+TRACE_DEFINE_ENUM(__REQ_NOIDLE);
+TRACE_DEFINE_ENUM(__REQ_FLUSH);
+TRACE_DEFINE_ENUM(__REQ_FUA);
+TRACE_DEFINE_ENUM(__REQ_PRIO);
+TRACE_DEFINE_ENUM(__REQ_META);
+TRACE_DEFINE_ENUM(CP_UMOUNT);
+TRACE_DEFINE_ENUM(CP_FASTBOOT);
+TRACE_DEFINE_ENUM(CP_SYNC);
+TRACE_DEFINE_ENUM(CP_DISCARD);
+
 #define show_block_type(type)						\
 	__print_symbolic(type,						\
 		{ NODE,		"NODE" },				\
-- 
2.1.4

[RFC][PATCH 13/17 v2] irq/tracing: Export enums in tracepoints to user space

[Steven Rostedt]

[-- Attachment #1: 0013-irq-tracing-Export-enums-in-tracepoints-to-user-spac.patch --]
[-- Type: text/plain, Size: 2074 bytes --]

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

The enums used by the softirq mapping is what is shown in the output
of the __print_symbolic() and not their values, that are needed
to map them to their strings. Export them to userspace with the
TRACE_DEFINE_ENUM() macro so that user space tools can map the enums
with their values.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/irq.h | 39 +++++++++++++++++++++++++++------------
 1 file changed, 27 insertions(+), 12 deletions(-)

diff --git a/include/trace/events/irq.h b/include/trace/events/irq.h
index 3608bebd3d9c..ff8f6c091a15 100644
--- a/include/trace/events/irq.h
+++ b/include/trace/events/irq.h
@@ -9,19 +9,34 @@
 struct irqaction;
 struct softirq_action;
 
-#define softirq_name(sirq) { sirq##_SOFTIRQ, #sirq }
+#define SOFTIRQ_NAME_LIST				\
+			 softirq_name(HI)		\
+			 softirq_name(TIMER)		\
+			 softirq_name(NET_TX)		\
+			 softirq_name(NET_RX)		\
+			 softirq_name(BLOCK)		\
+			 softirq_name(BLOCK_IOPOLL)	\
+			 softirq_name(TASKLET)		\
+			 softirq_name(SCHED)		\
+			 softirq_name(HRTIMER)		\
+			 softirq_name_end(RCU)
+
+#undef softirq_name
+#undef softirq_name_end
+
+#define softirq_name(sirq) TRACE_DEFINE_ENUM(sirq##_SOFTIRQ);
+#define softirq_name_end(sirq)  TRACE_DEFINE_ENUM(sirq##_SOFTIRQ);
+
+SOFTIRQ_NAME_LIST
+
+#undef softirq_name
+#undef softirq_name_end
+
+#define softirq_name(sirq) { sirq##_SOFTIRQ, #sirq },
+#define softirq_name_end(sirq) { sirq##_SOFTIRQ, #sirq }
+
 #define show_softirq_name(val)				\
-	__print_symbolic(val,				\
-			 softirq_name(HI),		\
-			 softirq_name(TIMER),		\
-			 softirq_name(NET_TX),		\
-			 softirq_name(NET_RX),		\
-			 softirq_name(BLOCK),		\
-			 softirq_name(BLOCK_IOPOLL),	\
-			 softirq_name(TASKLET),		\
-			 softirq_name(SCHED),		\
-			 softirq_name(HRTIMER),		\
-			 softirq_name(RCU))
+	__print_symbolic(val, SOFTIRQ_NAME_LIST)
 
 /**
  * irq_handler_entry - called immediately before the irq action handler
-- 
2.1.4

[RFC][PATCH 14/17 v2] mm: tracing: Export enums in tracepoints to user space

[Steven Rostedt]

[-- Attachment #1: 0014-mm-tracing-Export-enums-in-tracepoints-to-user-space.patch --]
[-- Type: text/plain, Size: 2260 bytes --]

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

The enums used in tracepoints with __print_symbolic() have their
names shown in the tracepoint format files and not their values.
This makes it difficult for user space tools to convert the binary
data to the strings as user space does not know what those enums
are about.

By having them use TRACE_DEFINE_ENUM(), the names of the enums will
be mapped to the values and shown to user space.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/migrate.h | 42 ++++++++++++++++++++++++++++++++----------
 1 file changed, 32 insertions(+), 10 deletions(-)

diff --git a/include/trace/events/migrate.h b/include/trace/events/migrate.h
index dd2b5467d905..539b25a76111 100644
--- a/include/trace/events/migrate.h
+++ b/include/trace/events/migrate.h
@@ -7,18 +7,40 @@
 #include <linux/tracepoint.h>
 
 #define MIGRATE_MODE						\
-	{MIGRATE_ASYNC,		"MIGRATE_ASYNC"},		\
-	{MIGRATE_SYNC_LIGHT,	"MIGRATE_SYNC_LIGHT"},		\
-	{MIGRATE_SYNC,		"MIGRATE_SYNC"}		
+	EM( MIGRATE_ASYNC,	"MIGRATE_ASYNC")		\
+	EM( MIGRATE_SYNC_LIGHT,	"MIGRATE_SYNC_LIGHT")		\
+	EMe(MIGRATE_SYNC,	"MIGRATE_SYNC")
+
 
 #define MIGRATE_REASON						\
-	{MR_COMPACTION,		"compaction"},			\
-	{MR_MEMORY_FAILURE,	"memory_failure"},		\
-	{MR_MEMORY_HOTPLUG,	"memory_hotplug"},		\
-	{MR_SYSCALL,		"syscall_or_cpuset"},		\
-	{MR_MEMPOLICY_MBIND,	"mempolicy_mbind"},		\
-	{MR_NUMA_MISPLACED,	"numa_misplaced"},		\
-	{MR_CMA,		"cma"}
+	EM( MR_COMPACTION,	"compaction")			\
+	EM( MR_MEMORY_FAILURE,	"memory_failure")		\
+	EM( MR_MEMORY_HOTPLUG,	"memory_hotplug")		\
+	EM( MR_SYSCALL,		"syscall_or_cpuset")		\
+	EM( MR_MEMPOLICY_MBIND,	"mempolicy_mbind")		\
+	EM( MR_NUMA_MISPLACED,	"numa_misplaced")		\
+	EMe(MR_CMA,		"cma")
+
+/*
+ * First define the enums in the above macros to be exported to userspace
+ * via TRACE_DEFINE_ENUM().
+ */
+#undef EM
+#undef EMe
+#define EM(a, b)	TRACE_DEFINE_ENUM(a);
+#define EMe(a, b)	TRACE_DEFINE_ENUM(a);
+
+MIGRATE_MODE
+MIGRATE_REASON
+
+/*
+ * Now redefine the EM() and EMe() macros to map the enums to the strings
+ * that will be printed in the output.
+ */
+#undef EM
+#undef EMe
+#define EM(a, b)	{a, b},
+#define EMe(a, b)	{a, b}
 
 TRACE_EVENT(mm_migrate_pages,
 
-- 
2.1.4

[RFC][PATCH 15/17 v2] SUNRPC: Export enums in tracepoints to user space

[Steven Rostedt]

[-- Attachment #1: 0015-SUNRPC-Export-enums-in-tracepoints-to-user-space.patch --]
[-- Type: text/plain, Size: 2834 bytes --]

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

The enums used in the tracepoints for __print_symbolic() have their
names shown in the tracepoint format files. User space tools do not know
how to convert those names into their values to be able to convert the
binary data.

Use TRACE_DEFINE_ENUM() to export the enum names to their values for
userspace to do the parsing correctly.

Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/sunrpc.h | 62 ++++++++++++++++++++++++++++++-------------
 1 file changed, 44 insertions(+), 18 deletions(-)

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index b9c1dc6c825a..fd1a02cb3c82 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -179,27 +179,53 @@ DEFINE_EVENT(rpc_task_queued, rpc_task_wakeup,
 
 );
 
+/*
+ * First define the enums in the below macros to be exported to userspace
+ * via TRACE_DEFINE_ENUM().
+ */
+#undef EM
+#undef EMe
+#define EM(a, b)	TRACE_DEFINE_ENUM(a);
+#define EMe(a, b)	TRACE_DEFINE_ENUM(a);
+
+#define RPC_SHOW_SOCKET				\
+	EM( SS_FREE, "FREE" )			\
+	EM( SS_UNCONNECTED, "UNCONNECTED" )	\
+	EM( SS_CONNECTING, "CONNECTING," )	\
+	EM( SS_CONNECTED, "CONNECTED," )	\
+	EMe(SS_DISCONNECTING, "DISCONNECTING" )
+
 #define rpc_show_socket_state(state) \
-	__print_symbolic(state, \
-		{ SS_FREE, "FREE" }, \
-		{ SS_UNCONNECTED, "UNCONNECTED" }, \
-		{ SS_CONNECTING, "CONNECTING," }, \
-		{ SS_CONNECTED, "CONNECTED," }, \
-		{ SS_DISCONNECTING, "DISCONNECTING" })
+	__print_symbolic(state, RPC_SHOW_SOCKET)
+
+RPC_SHOW_SOCKET
+
+#define RPC_SHOW_SOCK				\
+	EM( TCP_ESTABLISHED, "ESTABLISHED" )	\
+	EM( TCP_SYN_SENT, "SYN_SENT" )		\
+	EM( TCP_SYN_RECV, "SYN_RECV" )		\
+	EM( TCP_FIN_WAIT1, "FIN_WAIT1" )	\
+	EM( TCP_FIN_WAIT2, "FIN_WAIT2" )	\
+	EM( TCP_TIME_WAIT, "TIME_WAIT" )	\
+	EM( TCP_CLOSE, "CLOSE" )		\
+	EM( TCP_CLOSE_WAIT, "CLOSE_WAIT" )	\
+	EM( TCP_LAST_ACK, "LAST_ACK" )		\
+	EM( TCP_LISTEN, "LISTEN" )		\
+	EMe( TCP_CLOSING, "CLOSING" )
 
 #define rpc_show_sock_state(state) \
-	__print_symbolic(state, \
-		{ TCP_ESTABLISHED, "ESTABLISHED" }, \
-		{ TCP_SYN_SENT, "SYN_SENT" }, \
-		{ TCP_SYN_RECV, "SYN_RECV" }, \
-		{ TCP_FIN_WAIT1, "FIN_WAIT1" }, \
-		{ TCP_FIN_WAIT2, "FIN_WAIT2" }, \
-		{ TCP_TIME_WAIT, "TIME_WAIT" }, \
-		{ TCP_CLOSE, "CLOSE" }, \
-		{ TCP_CLOSE_WAIT, "CLOSE_WAIT" }, \
-		{ TCP_LAST_ACK, "LAST_ACK" }, \
-		{ TCP_LISTEN, "LISTEN" }, \
-		{ TCP_CLOSING, "CLOSING" })
+	__print_symbolic(state, RPC_SHOW_SOCK)
+
+RPC_SHOW_SOCK
+
+/*
+ * Now redefine the EM() and EMe() macros to map the enums to the strings
+ * that will be printed in the output.
+ */
+#undef EM
+#undef EMe
+#define EM(a, b)	{a, b},
+#define EMe(a, b)	{a, b}
 
 DECLARE_EVENT_CLASS(xs_socket_event,
 
-- 
2.1.4

[RFC][PATCH 16/17 v2] v4l: Export enums used by tracepoints to user space

[Steven Rostedt]

[-- Attachment #1: 0016-v4l-Export-enums-used-by-tracepoints-to-user-space.patch --]
[-- Type: text/plain, Size: 4177 bytes --]

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

Enums used by tracepoints for __print_symbolic() are shown in the
tracepoint format files with just their names and not their values.
This makes it difficult for user space tools to know how to convert the
binary data into their string representations.

By adding the use of TRACE_DEFINE_ENUM(), the enum names will be mapped
to their values and shown in the tracing file system to let tools
convert the data as necessary.

Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/v4l2.h | 75 ++++++++++++++++++++++++++++++---------------
 1 file changed, 50 insertions(+), 25 deletions(-)

diff --git a/include/trace/events/v4l2.h b/include/trace/events/v4l2.h
index b9bb1f204693..20112170ff11 100644
--- a/include/trace/events/v4l2.h
+++ b/include/trace/events/v4l2.h
@@ -6,33 +6,58 @@
 
 #include <linux/tracepoint.h>
 
-#define show_type(type)							       \
-	__print_symbolic(type,						       \
-		{ V4L2_BUF_TYPE_VIDEO_CAPTURE,	      "VIDEO_CAPTURE" },       \
-		{ V4L2_BUF_TYPE_VIDEO_OUTPUT,	      "VIDEO_OUTPUT" },	       \
-		{ V4L2_BUF_TYPE_VIDEO_OVERLAY,	      "VIDEO_OVERLAY" },       \
-		{ V4L2_BUF_TYPE_VBI_CAPTURE,	      "VBI_CAPTURE" },	       \
-		{ V4L2_BUF_TYPE_VBI_OUTPUT,	      "VBI_OUTPUT" },	       \
-		{ V4L2_BUF_TYPE_SLICED_VBI_CAPTURE,   "SLICED_VBI_CAPTURE" },  \
-		{ V4L2_BUF_TYPE_SLICED_VBI_OUTPUT,    "SLICED_VBI_OUTPUT" },   \
-		{ V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY, "VIDEO_OUTPUT_OVERLAY" },\
-		{ V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE, "VIDEO_CAPTURE_MPLANE" },\
-		{ V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE,  "VIDEO_OUTPUT_MPLANE" }, \
-		{ V4L2_BUF_TYPE_SDR_CAPTURE,          "SDR_CAPTURE" },         \
-		{ V4L2_BUF_TYPE_PRIVATE,	      "PRIVATE" })
+/* Enums require being exported to userspace, for user tool parsing */
+#undef EM
+#undef EMe
+#define EM(a, b)	TRACE_DEFINE_ENUM(a);
+#define EMe(a, b)	TRACE_DEFINE_ENUM(a);
+
+#define show_type(type)							\
+	__print_symbolic(type, SHOW_TYPE)
+
+#define SHOW_TYPE							\
+	EM( V4L2_BUF_TYPE_VIDEO_CAPTURE,	"VIDEO_CAPTURE" )	\
+	EM( V4L2_BUF_TYPE_VIDEO_OUTPUT,		"VIDEO_OUTPUT" )	\
+	EM( V4L2_BUF_TYPE_VIDEO_OVERLAY,	"VIDEO_OVERLAY" )	\
+	EM( V4L2_BUF_TYPE_VBI_CAPTURE,		"VBI_CAPTURE" )		\
+	EM( V4L2_BUF_TYPE_VBI_OUTPUT,		"VBI_OUTPUT" )		\
+	EM( V4L2_BUF_TYPE_SLICED_VBI_CAPTURE,   "SLICED_VBI_CAPTURE" )	\
+	EM( V4L2_BUF_TYPE_SLICED_VBI_OUTPUT,    "SLICED_VBI_OUTPUT" )	\
+	EM( V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY, "VIDEO_OUTPUT_OVERLAY" ) \
+	EM( V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE, "VIDEO_CAPTURE_MPLANE" ) \
+	EM( V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE,  "VIDEO_OUTPUT_MPLANE" )	\
+	EM( V4L2_BUF_TYPE_SDR_CAPTURE,          "SDR_CAPTURE" )		\
+	EMe(V4L2_BUF_TYPE_PRIVATE,		"PRIVATE" )
+
+SHOW_TYPE
 
 #define show_field(field)						\
-	__print_symbolic(field,						\
-		{ V4L2_FIELD_ANY,		"ANY" },		\
-		{ V4L2_FIELD_NONE,		"NONE" },		\
-		{ V4L2_FIELD_TOP,		"TOP" },		\
-		{ V4L2_FIELD_BOTTOM,		"BOTTOM" },		\
-		{ V4L2_FIELD_INTERLACED,	"INTERLACED" },		\
-		{ V4L2_FIELD_SEQ_TB,		"SEQ_TB" },		\
-		{ V4L2_FIELD_SEQ_BT,		"SEQ_BT" },		\
-		{ V4L2_FIELD_ALTERNATE,		"ALTERNATE" },		\
-		{ V4L2_FIELD_INTERLACED_TB,	"INTERLACED_TB" },      \
-		{ V4L2_FIELD_INTERLACED_BT,	"INTERLACED_BT" })
+	__print_symbolic(field, SHOW_FIELD)
+
+#define SHOW_FIELD							\
+	EM( V4L2_FIELD_ANY,		"ANY" )				\
+	EM( V4L2_FIELD_NONE,		"NONE" )			\
+	EM( V4L2_FIELD_TOP,		"TOP" )				\
+	EM( V4L2_FIELD_BOTTOM,		"BOTTOM" )			\
+	EM( V4L2_FIELD_INTERLACED,	"INTERLACED" )			\
+	EM( V4L2_FIELD_SEQ_TB,		"SEQ_TB" )			\
+	EM( V4L2_FIELD_SEQ_BT,		"SEQ_BT" )			\
+	EM( V4L2_FIELD_ALTERNATE,	"ALTERNATE" )			\
+	EM( V4L2_FIELD_INTERLACED_TB,	"INTERLACED_TB" )		\
+	EMe( V4L2_FIELD_INTERLACED_BT,	"INTERLACED_BT" )
+
+SHOW_FIELD
+
+/*
+ * Now redefine the EM() and EMe() macros to map the enums to the strings
+ * that will be printed in the output.
+ */
+#undef EM
+#undef EMe
+#define EM(a, b)	{a, b},
+#define EMe(a, b)	{a, b}
+
+/* V4L2_TC_TYPE_* are macros, not defines, they do not need processing */
 
 #define show_timecode_type(type)					\
 	__print_symbolic(type,						\
-- 
2.1.4

[RFC][PATCH 17/17 v2] writeback: Export enums used by tracepoint to user space

[Steven Rostedt]

[-- Attachment #1: 0017-writeback-Export-enums-used-by-tracepoint-to-user-sp.patch --]
[-- Type: text/plain, Size: 2149 bytes --]

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

The enums used in tracepoints for __print_symbolic() do not have their
values shown in the tracepoint format files and this makes it difficult
for user space tools to convert the binary values to the strings they
are to represent.

Add TRACE_DEFINE_ENUM(x) macros to export the enum names to their values
to make the tracing output from user space tools more robust.

Cc: Dave Chinner <dchinner@redhat.com>
Cc: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/writeback.h | 33 +++++++++++++++++++++++++--------
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index 5a14ead59696..880dd7437172 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -23,15 +23,32 @@
 		{I_REFERENCED,		"I_REFERENCED"}		\
 	)
 
+/* enums need to be exported to user space */
+#undef EM
+#undef EMe
+#define EM(a,b) 	TRACE_DEFINE_ENUM(a);
+#define EMe(a,b)	TRACE_DEFINE_ENUM(a);
+
 #define WB_WORK_REASON							\
-		{WB_REASON_BACKGROUND,		"background"},		\
-		{WB_REASON_TRY_TO_FREE_PAGES,	"try_to_free_pages"},	\
-		{WB_REASON_SYNC,		"sync"},		\
-		{WB_REASON_PERIODIC,		"periodic"},		\
-		{WB_REASON_LAPTOP_TIMER,	"laptop_timer"},	\
-		{WB_REASON_FREE_MORE_MEM,	"free_more_memory"},	\
-		{WB_REASON_FS_FREE_SPACE,	"fs_free_space"},	\
-		{WB_REASON_FORKER_THREAD,	"forker_thread"}
+	EM( WB_REASON_BACKGROUND,		"background")		\
+	EM( WB_REASON_TRY_TO_FREE_PAGES,	"try_to_free_pages")	\
+	EM( WB_REASON_SYNC,			"sync")			\
+	EM( WB_REASON_PERIODIC,			"periodic")		\
+	EM( WB_REASON_LAPTOP_TIMER,		"laptop_timer")		\
+	EM( WB_REASON_FREE_MORE_MEM,		"free_more_memory")	\
+	EM( WB_REASON_FS_FREE_SPACE,		"fs_free_space")	\
+	EMe(WB_REASON_FORKER_THREAD,		"forker_thread")
+
+WB_WORK_REASON
+
+/*
+ * Now redefine the EM() and EMe() macros to map the enums to the strings
+ * that will be printed in the output.
+ */
+#undef EM
+#undef EMe
+#define EM(a,b)		{ a, b },
+#define EMe(a,b)	{ a, b }
 
 struct wb_writeback_work;
 
-- 
2.1.4

Re: [RFC][PATCH 00/17 v2] tracing: Use TRACE_DEFINE_ENUM() to show enum values

[Masami Hiramatsu]

(2015/04/02 10:56), Steven Rostedt wrote:
> As there are many tracepoints that use __print_symbolic() to translate
> numbers into ASCII strings, and several of these translate enums as
> well, it causes a problem for user space tools that read the tracepoint
> format files and have to translate the binary data to their associated
> strings.
> 
> For example, with the tlb_flush tracepoint, we have this in the format
> file:
> 
> print fmt: "pages:%ld reason:%s (%d)", REC->pages,
>  __print_symbolic(REC->reason,
>    { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" },
>    { TLB_REMOTE_SHOOTDOWN, "remote shootdown" },
>    { TLB_LOCAL_SHOOTDOWN, "local shootdown" },
>    { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }), REC->reason
> 
> Now, userspace does not know what the value of TLB_REMOTE_SHOOTDOWN is.
> To solve this, a new macro is created as a helper to allow tracepoints
> to export enums they use to userspace. This macro is called,
> TRACE_DEFINE_ENUM(), such that
> 
>  TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN);
> 
> will convert the "print fmt"s in the format files to its actual value
> and no longer display the enum name.
> 
> On boot up (or module load), the enums saved via TRACE_DEFINE_ENUM()
> will be searched for in the TP_printk()s of the tracepoints. Logic
> knows enough to ignore quoted text.
> 
> For debugging, a new file is still added in the tracing directory
> to show what enums were added, their values and the TRACE_SYSTEM that
> added them:
> 
>  # cat /sys/kernel/debug/tracing/enum_map
> TLB_LOCAL_MM_SHOOTDOWN 3 (tlb)
> TLB_LOCAL_SHOOTDOWN 2 (tlb)
> TLB_REMOTE_SHOOTDOWN 1 (tlb)
> TLB_FLUSH_ON_TASK_SWITCH 0 (tlb)
> 
> And the output of the tlb_flush format is now:
> 
> print fmt: "pages:%ld reason:%s (%d)", REC->pages,
>  __print_symbolic(REC->reason,
>    { 0, "flush on task switch" },
>    { 1, "remote shootdown" },
>    { 2, "local shootdown" },
>    { 3, "local mm shootdown" }), REC->reason
> 
> And userspace tools can easily parse that without special handling.

Great! :)
Thank you for updating the series :D
Now I'm OK for this series.

> 
> Local SHA1: a6862181206543b6493c73690f322868c86de0ea
> 
> 
> Steven Rostedt (Red Hat) (17):
>       tracing: Add TRACE_SYSTEM_VAR to intel-sst
>       tracing: Add TRACE_SYSTEM_VAR to kvm-s390
>       tracing: Add TRACE_SYSTEM_VAR to xhci-hcd
>       tracing: Give system name a pointer
>       tracing: Update trace-event-sample with TRACE_SYSTEM_VAR documentation
>       tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values
>       tracing: Allow for modules to export their trace enums as well
>       tracing/samples: Update the trace-event-sample.h with TRACE_DEFINE_ENUM()
>       tracing: Show the mapped enums in enum_map file
>       x86/tlb/trace: Export enums in used by tlb_flush tracepoint
>       net/9p/tracing: Export enums in tracepoints to userspace
>       f2fs: Export the enums in the tracepoints to userspace
>       irq/tracing: Export enums in tracepoints to user space
>       mm: tracing: Export enums in tracepoints to user space
>       SUNRPC: Export enums in tracepoints to user space
>       v4l: Export enums used by tracepoints to user space
>       writeback: Export enums used by tracepoint to user space
> 
> ----
>  arch/s390/kvm/trace-s390.h                 |   7 +
>  drivers/usb/host/xhci-trace.h              |   7 +
>  include/asm-generic/vmlinux.lds.h          |   5 +-
>  include/linux/ftrace_event.h               |   4 +-
>  include/linux/module.h                     |   2 +
>  include/linux/tracepoint.h                 |   8 +
>  include/trace/events/9p.h                  | 157 ++++++++--------
>  include/trace/events/f2fs.h                |  30 ++++
>  include/trace/events/intel-sst.h           |   7 +
>  include/trace/events/irq.h                 |  39 ++--
>  include/trace/events/migrate.h             |  42 +++--
>  include/trace/events/sunrpc.h              |  62 +++++--
>  include/trace/events/tlb.h                 |  30 +++-
>  include/trace/events/v4l2.h                |  75 +++++---
>  include/trace/events/writeback.h           |  33 +++-
>  include/trace/ftrace.h                     |  41 ++++-
>  kernel/module.c                            |   3 +
>  kernel/trace/trace.c                       | 276 ++++++++++++++++++++++++++++-
>  kernel/trace/trace.h                       |   2 +
>  kernel/trace/trace_events.c                |  98 +++++++++-
>  samples/trace_events/trace-events-sample.h |  84 ++++++++-
>  21 files changed, 853 insertions(+), 159 deletions(-)
> 
> 


-- 
Masami HIRAMATSU
Linux Technology Research Center, System Productivity Research Dept.
Center for Technology Innovation - Systems Engineering
Hitachi, Ltd., Research & Development Group
E-mail: masami.hiramatsu.pt@hitachi.com