* [PATCH v2 0/3] TLB flush counters
@ 2019-04-29 19:57 Atish Patra
2019-04-29 19:57 ` [PATCH v2 1/3] x86: Move DEBUG_TLBFLUSH option Atish Patra
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Atish Patra @ 2019-04-29 19:57 UTC (permalink / raw)
To: linux-kernel
Cc: Atish Patra, Albert Ou, Andrew Morton, Anup Patel,
Borislav Petkov, Changbin Du, Gary Guo, H. Peter Anvin,
Ingo Molnar, Kees Cook, linux-mm, linux-riscv,
Luc Van Oostenryck, Palmer Dabbelt, Thomas Gleixner,
Vlastimil Babka, maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
Christoph Hellwig
The RISC-V patch (2/3) is based on Gary's TLB flush patch series
https://patchwork.kernel.org/project/linux-riscv/list/?series=97315
The x86 kconfig fix patch(1/3) can be applied separately.
Changes from v1->v2:
1. Move the arch specific config option to a common one as it touches
generic code.
2. Introduced another config that architectures can select to enable
tlbflush option.
Atish Patra (3):
x86: Move DEBUG_TLBFLUSH option.
RISC-V: Enable TLBFLUSH counters for debug kernel.
RISC-V: Update tlb flush counters
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/tlbflush.h | 5 +++++
arch/riscv/mm/tlbflush.c | 12 ++++++++++++
arch/x86/Kconfig | 1 +
arch/x86/Kconfig.debug | 19 -------------------
mm/Kconfig.debug | 13 +++++++++++++
6 files changed, 32 insertions(+), 19 deletions(-)
--
2.21.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2 1/3] x86: Move DEBUG_TLBFLUSH option.
2019-04-29 19:57 [PATCH v2 0/3] TLB flush counters Atish Patra
@ 2019-04-29 19:57 ` Atish Patra
2019-04-29 20:05 ` Ingo Molnar
2019-04-29 19:57 ` [PATCH v2 2/3] RISC-V: Enable TLBFLUSH counters for debug kernel Atish Patra
2019-04-29 19:57 ` [PATCH v2 3/3] RISC-V: Update tlb flush counters Atish Patra
2 siblings, 1 reply; 6+ messages in thread
From: Atish Patra @ 2019-04-29 19:57 UTC (permalink / raw)
To: linux-kernel
Cc: Atish Patra, Albert Ou, Andrew Morton, Anup Patel,
Borislav Petkov, Changbin Du, Gary Guo, H. Peter Anvin,
Ingo Molnar, Kees Cook, linux-mm, linux-riscv,
Luc Van Oostenryck, Palmer Dabbelt, Thomas Gleixner,
Vlastimil Babka, maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
Christoph Hellwig
CONFIG_DEBUG_TLBFLUSH was added in 'commit 3df3212f9722 ("x86/tlb: add
tlb_flushall_shift knob into debugfs")' to support tlb_flushall_shift
knob. The knob was removed in 'commit e9f4e0a9fe27 ("x86/mm: Rip out
complicated, out-of-date, buggy TLB flushing")'. However, the debug
option was never removed from Kconfig. It was reused in commit
'9824cf9753ec ("mm: vmstats: tlb flush counters")' but the commit text
was never updated accordingly.
Update the Kconfig option description as per its current usage.
Take this opprtunity to make this kconfig option a common option as it
touches the common vmstat code. Introduce another arch specific config
HAVE_ARCH_DEBUG_TLBFLUSH that can be selected to enable this config.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
---
arch/x86/Kconfig | 1 +
arch/x86/Kconfig.debug | 19 -------------------
mm/Kconfig.debug | 13 +++++++++++++
3 files changed, 14 insertions(+), 19 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 62fc3fda1a05..4c59f59e9491 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -132,6 +132,7 @@ config X86
select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
select HAVE_ARCH_VMAP_STACK if X86_64
select HAVE_ARCH_WITHIN_STACK_FRAMES
+ select HAVE_ARCH_DEBUG_TLBFLUSH if DEBUG_KERNEL
select HAVE_CMPXCHG_DOUBLE
select HAVE_CMPXCHG_LOCAL
select HAVE_CONTEXT_TRACKING if X86_64
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 15d0fbe27872..0c8f9931e901 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -124,25 +124,6 @@ config DOUBLEFAULT
option saves about 4k and might cause you much additional grey
hair.
-config DEBUG_TLBFLUSH
- bool "Set upper limit of TLB entries to flush one-by-one"
- depends on DEBUG_KERNEL
- ---help---
-
- X86-only for now.
-
- This option allows the user to tune the amount of TLB entries the
- kernel flushes one-by-one instead of doing a full TLB flush. In
- certain situations, the former is cheaper. This is controlled by the
- tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it
- to -1, the code flushes the whole TLB unconditionally. Otherwise,
- for positive values of it, the kernel will use single TLB entry
- invalidating instructions according to the following formula:
-
- flush_entries <= active_tlb_entries / 2^tlb_flushall_shift
-
- If in doubt, say "N".
-
config IOMMU_DEBUG
bool "Enable IOMMU debugging"
depends on GART_IOMMU && DEBUG_KERNEL
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index e3df921208c0..760c3fda8b57 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -111,3 +111,16 @@ config DEBUG_RODATA_TEST
depends on STRICT_KERNEL_RWX
---help---
This option enables a testcase for the setting rodata read-only.
+
+config HAVE_ARCH_DEBUG_TLBFLUSH
+ bool
+ depends on DEBUG_KERNEL
+
+config DEBUG_TLBFLUSH
+ bool "Save tlb flush statstics to vmstat"
+ depends on HAVE_ARCH_DEBUG_TLBFLUSH
+ help
+
+ Add tlbflush statstics to vmstat. It is really helpful understand tlbflush
+ performance and behavior. It should be enabled only for debugging purpose
+ by individual architectures explicitly by selecting HAVE_ARCH_DEBUG_TLBFLUSH.
--
2.21.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 2/3] RISC-V: Enable TLBFLUSH counters for debug kernel.
2019-04-29 19:57 [PATCH v2 0/3] TLB flush counters Atish Patra
2019-04-29 19:57 ` [PATCH v2 1/3] x86: Move DEBUG_TLBFLUSH option Atish Patra
@ 2019-04-29 19:57 ` Atish Patra
2019-04-29 19:57 ` [PATCH v2 3/3] RISC-V: Update tlb flush counters Atish Patra
2 siblings, 0 replies; 6+ messages in thread
From: Atish Patra @ 2019-04-29 19:57 UTC (permalink / raw)
To: linux-kernel
Cc: Atish Patra, Albert Ou, Andrew Morton, Anup Patel,
Borislav Petkov, Changbin Du, Gary Guo, H. Peter Anvin,
Ingo Molnar, Kees Cook, linux-mm, linux-riscv,
Luc Van Oostenryck, Palmer Dabbelt, Thomas Gleixner,
Vlastimil Babka, maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
Christoph Hellwig
The TLB flush counters under vmstat seems to be very helpful while
debugging TLB flush performance in RISC-V.
Add the Kconfig option only for debug kernels.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
---
arch/riscv/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index eb56c82d8aa1..c1ee876d1e7f 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -49,6 +49,7 @@ config RISCV
select GENERIC_IRQ_MULTI_HANDLER
select ARCH_HAS_PTE_SPECIAL
select HAVE_EBPF_JIT if 64BIT
+ select HAVE_ARCH_DEBUG_TLBFLUSH if DEBUG_KERNEL
config MMU
def_bool y
--
2.21.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 3/3] RISC-V: Update tlb flush counters
2019-04-29 19:57 [PATCH v2 0/3] TLB flush counters Atish Patra
2019-04-29 19:57 ` [PATCH v2 1/3] x86: Move DEBUG_TLBFLUSH option Atish Patra
2019-04-29 19:57 ` [PATCH v2 2/3] RISC-V: Enable TLBFLUSH counters for debug kernel Atish Patra
@ 2019-04-29 19:57 ` Atish Patra
2 siblings, 0 replies; 6+ messages in thread
From: Atish Patra @ 2019-04-29 19:57 UTC (permalink / raw)
To: linux-kernel
Cc: Atish Patra, Albert Ou, Andrew Morton, Anup Patel,
Borislav Petkov, Changbin Du, Gary Guo, H. Peter Anvin,
Ingo Molnar, Kees Cook, linux-mm, linux-riscv,
Luc Van Oostenryck, Palmer Dabbelt, Thomas Gleixner,
Vlastimil Babka, maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
Christoph Hellwig
The TLB flush counters under vmstat seems to be very helpful while
debugging TLB flush performance in RISC-V.
Update the counters in every TLB flush methods respectively.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
---
arch/riscv/include/asm/tlbflush.h | 5 +++++
arch/riscv/mm/tlbflush.c | 12 ++++++++++++
2 files changed, 17 insertions(+)
diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
index 29a780ca232a..19779a083f52 100644
--- a/arch/riscv/include/asm/tlbflush.h
+++ b/arch/riscv/include/asm/tlbflush.h
@@ -9,6 +9,7 @@
#define _ASM_RISCV_TLBFLUSH_H
#include <linux/mm_types.h>
+#include <linux/vmstat.h>
/*
* Flush entire local TLB. 'sfence.vma' implicitly fences with the instruction
@@ -16,11 +17,13 @@
*/
static inline void local_flush_tlb_all(void)
{
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
__asm__ __volatile__ ("sfence.vma" : : : "memory");
}
static inline void local_flush_tlb_mm(struct mm_struct *mm)
{
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
/* Flush ASID 0 so that global mappings are not affected */
__asm__ __volatile__ ("sfence.vma x0, %0" : : "r" (0) : "memory");
}
@@ -28,6 +31,7 @@ static inline void local_flush_tlb_mm(struct mm_struct *mm)
static inline void local_flush_tlb_page(struct vm_area_struct *vma,
unsigned long addr)
{
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ONE);
__asm__ __volatile__ ("sfence.vma %0, %1"
: : "r" (addr), "r" (0)
: "memory");
@@ -35,6 +39,7 @@ static inline void local_flush_tlb_page(struct vm_area_struct *vma,
static inline void local_flush_tlb_kernel_page(unsigned long addr)
{
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ONE);
__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory");
}
diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
index ceee76f14a0a..8072d7da32bb 100644
--- a/arch/riscv/mm/tlbflush.c
+++ b/arch/riscv/mm/tlbflush.c
@@ -4,6 +4,8 @@
*/
#include <linux/mm.h>
+#include <linux/vmstat.h>
+#include <linux/cpumask.h>
#include <asm/sbi.h>
#define SFENCE_VMA_FLUSH_ALL ((unsigned long) -1)
@@ -110,6 +112,7 @@ static void ipi_remote_sfence_vma(void *info)
unsigned long size = data->size;
unsigned long i;
+ count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
if (size == SFENCE_VMA_FLUSH_ALL) {
local_flush_tlb_all();
}
@@ -129,6 +132,8 @@ static void ipi_remote_sfence_vma_asid(void *info)
unsigned long size = data->size;
unsigned long i;
+ count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
+ /* Flush entire MM context */
if (size == SFENCE_VMA_FLUSH_ALL) {
__asm__ __volatile__ ("sfence.vma x0, %0"
: : "r" (asid)
@@ -158,6 +163,13 @@ static void remote_sfence_vma(unsigned long start, unsigned long size)
static void remote_sfence_vma_asid(cpumask_t *mask, unsigned long start,
unsigned long size, unsigned long asid)
{
+ int cpuid = smp_processor_id();
+
+ if (cpumask_equal(mask, cpumask_of(cpuid)))
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
+ else
+ count_vm_tlb_event(NR_TLB_REMOTE_FLUSH);
+
if (tlbi_ipi) {
struct tlbi info = {
.start = start,
--
2.21.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2 1/3] x86: Move DEBUG_TLBFLUSH option.
2019-04-29 19:57 ` [PATCH v2 1/3] x86: Move DEBUG_TLBFLUSH option Atish Patra
@ 2019-04-29 20:05 ` Ingo Molnar
2019-04-29 21:29 ` Atish Patra
0 siblings, 1 reply; 6+ messages in thread
From: Ingo Molnar @ 2019-04-29 20:05 UTC (permalink / raw)
To: Atish Patra
Cc: linux-kernel, Albert Ou, Andrew Morton, Anup Patel,
Borislav Petkov, Changbin Du, Gary Guo, H. Peter Anvin,
Ingo Molnar, Kees Cook, linux-mm, linux-riscv,
Luc Van Oostenryck, Palmer Dabbelt, Thomas Gleixner,
Vlastimil Babka, maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
Christoph Hellwig
* Atish Patra <atish.patra@wdc.com> wrote:
> CONFIG_DEBUG_TLBFLUSH was added in 'commit 3df3212f9722 ("x86/tlb: add
> tlb_flushall_shift knob into debugfs")' to support tlb_flushall_shift
> knob. The knob was removed in 'commit e9f4e0a9fe27 ("x86/mm: Rip out
> complicated, out-of-date, buggy TLB flushing")'. However, the debug
> option was never removed from Kconfig. It was reused in commit
> '9824cf9753ec ("mm: vmstats: tlb flush counters")' but the commit text
> was never updated accordingly.
Please, when you mention several commits, put them into new lines to make
it readable, i.e.:
3df3212f9722 ("x86/tlb: add tlb_flushall_shift knob into debugfs")
etc.
> Update the Kconfig option description as per its current usage.
>
> Take this opprtunity to make this kconfig option a common option as it
> touches the common vmstat code. Introduce another arch specific config
> HAVE_ARCH_DEBUG_TLBFLUSH that can be selected to enable this config.
"opprtunity"?
> +config HAVE_ARCH_DEBUG_TLBFLUSH
> + bool
> + depends on DEBUG_KERNEL
> +
> +config DEBUG_TLBFLUSH
> + bool "Save tlb flush statstics to vmstat"
> + depends on HAVE_ARCH_DEBUG_TLBFLUSH
> + help
> +
> + Add tlbflush statstics to vmstat. It is really helpful understand tlbflush
> + performance and behavior. It should be enabled only for debugging purpose
> + by individual architectures explicitly by selecting HAVE_ARCH_DEBUG_TLBFLUSH.
"statstics"??
Please put a spell checker into your workflow or read what you are
writing ...
Thanks,
Ingo
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2 1/3] x86: Move DEBUG_TLBFLUSH option.
2019-04-29 20:05 ` Ingo Molnar
@ 2019-04-29 21:29 ` Atish Patra
0 siblings, 0 replies; 6+ messages in thread
From: Atish Patra @ 2019-04-29 21:29 UTC (permalink / raw)
To: Ingo Molnar
Cc: linux-kernel, Albert Ou, Andrew Morton, Anup Patel,
Borislav Petkov, Changbin Du, Gary Guo, H. Peter Anvin,
Ingo Molnar, Kees Cook, linux-mm, linux-riscv,
Luc Van Oostenryck, Palmer Dabbelt, Thomas Gleixner,
Vlastimil Babka, maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
Christoph Hellwig
On 4/29/19 1:06 PM, Ingo Molnar wrote:
>
> * Atish Patra <atish.patra@wdc.com> wrote:
>
>> CONFIG_DEBUG_TLBFLUSH was added in 'commit 3df3212f9722 ("x86/tlb: add
>> tlb_flushall_shift knob into debugfs")' to support tlb_flushall_shift
>> knob. The knob was removed in 'commit e9f4e0a9fe27 ("x86/mm: Rip out
>> complicated, out-of-date, buggy TLB flushing")'. However, the debug
>> option was never removed from Kconfig. It was reused in commit
>> '9824cf9753ec ("mm: vmstats: tlb flush counters")' but the commit text
>> was never updated accordingly.
>
> Please, when you mention several commits, put them into new lines to make
> it readable, i.e.:
>
> 3df3212f9722 ("x86/tlb: add tlb_flushall_shift knob into debugfs")
>
> etc.
>
Done.
>> Update the Kconfig option description as per its current usage.
>>
>> Take this opprtunity to make this kconfig option a common option as it
>> touches the common vmstat code. Introduce another arch specific config
>> HAVE_ARCH_DEBUG_TLBFLUSH that can be selected to enable this config.
>
> "opprtunity"?
>
>> +config HAVE_ARCH_DEBUG_TLBFLUSH
>> + bool
>> + depends on DEBUG_KERNEL
>> +
>> +config DEBUG_TLBFLUSH
>> + bool "Save tlb flush statstics to vmstat"
>> + depends on HAVE_ARCH_DEBUG_TLBFLUSH
>> + help
>> +
>> + Add tlbflush statstics to vmstat. It is really helpful understand tlbflush
>> + performance and behavior. It should be enabled only for debugging purpose
>> + by individual architectures explicitly by selecting HAVE_ARCH_DEBUG_TLBFLUSH.
>
> "statstics"??
>
> Please put a spell checker into your workflow or read what you are
> writing ...
>
Apologies for the typos. Fixed them.
Regards,
Atish
> Thanks,
>
> Ingo
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-04-29 21:29 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2019-04-29 19:57 [PATCH v2 0/3] TLB flush counters Atish Patra
2019-04-29 19:57 ` [PATCH v2 1/3] x86: Move DEBUG_TLBFLUSH option Atish Patra
2019-04-29 20:05 ` Ingo Molnar
2019-04-29 21:29 ` Atish Patra
2019-04-29 19:57 ` [PATCH v2 2/3] RISC-V: Enable TLBFLUSH counters for debug kernel Atish Patra
2019-04-29 19:57 ` [PATCH v2 3/3] RISC-V: Update tlb flush counters Atish Patra
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