* [PATCH] percpu: make this_cpu_generic_read notrace
@ 2016-09-10 8:45 Chunyan Zhang
2016-09-16 8:42 ` Chunyan Zhang
0 siblings, 1 reply; 6+ messages in thread
From: Chunyan Zhang @ 2016-09-10 8:45 UTC (permalink / raw)
To: arnd; +Cc: linux-arch, linux-kernel, zhang.lyra
When debug preempt or preempt tracer is enabled, preempt_count_add/sub()
can be traced by function and function graph tracing, and
preempt_disable/enable() would call preempt_count_add/sub(), so
we should use preempt_disable/enable_notrace in Ftrace subsystem.
The function this_cpu_read() started being used by function graph tracing
after the commit 345ddcc882d8 ("ftrace: Have set_ftrace_pid use the
bitmap like events do"), so it has to use preempt_disable/enable_notrace
instead now.
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
---
include/asm-generic/percpu.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index 4d9f233..70fefec 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -108,9 +108,9 @@ do { \
#define this_cpu_generic_read(pcp) \
({ \
typeof(pcp) __ret; \
- preempt_disable(); \
+ preempt_disable_notrace(); \
__ret = *this_cpu_ptr(&(pcp)); \
- preempt_enable(); \
+ preempt_enable_notrace(); \
__ret; \
})
--
2.7.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] percpu: make this_cpu_generic_read notrace
2016-09-10 8:45 [PATCH] percpu: make this_cpu_generic_read notrace Chunyan Zhang
@ 2016-09-16 8:42 ` Chunyan Zhang
2016-09-16 9:53 ` Will Deacon
0 siblings, 1 reply; 6+ messages in thread
From: Chunyan Zhang @ 2016-09-16 8:42 UTC (permalink / raw)
To: Arnd Bergmann, Will Deacon, Steven Rostedt
Cc: linux-arch, linux-kernel, Lyra Zhang
Hi Will and Steven,
May I have a review or an acked-by from you on this patch so that Arnd
can pick it up.
I have tested this patch on arm qemu, I'm sure it can solve the
problem described in commit message.
Thanks,
Chunyan
On 10 September 2016 at 16:45, Chunyan Zhang <zhang.chunyan@linaro.org> wrote:
> When debug preempt or preempt tracer is enabled, preempt_count_add/sub()
> can be traced by function and function graph tracing, and
> preempt_disable/enable() would call preempt_count_add/sub(), so
> we should use preempt_disable/enable_notrace in Ftrace subsystem.
>
> The function this_cpu_read() started being used by function graph tracing
> after the commit 345ddcc882d8 ("ftrace: Have set_ftrace_pid use the
> bitmap like events do"), so it has to use preempt_disable/enable_notrace
> instead now.
>
> Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
> ---
> include/asm-generic/percpu.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
> index 4d9f233..70fefec 100644
> --- a/include/asm-generic/percpu.h
> +++ b/include/asm-generic/percpu.h
> @@ -108,9 +108,9 @@ do { \
> #define this_cpu_generic_read(pcp) \
> ({ \
> typeof(pcp) __ret; \
> - preempt_disable(); \
> + preempt_disable_notrace(); \
> __ret = *this_cpu_ptr(&(pcp)); \
> - preempt_enable(); \
> + preempt_enable_notrace(); \
> __ret; \
> })
>
> --
> 2.7.4
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] percpu: make this_cpu_generic_read notrace
2016-09-16 8:42 ` Chunyan Zhang
@ 2016-09-16 9:53 ` Will Deacon
2016-09-16 10:08 ` Chunyan Zhang
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Will Deacon @ 2016-09-16 9:53 UTC (permalink / raw)
To: Chunyan Zhang
Cc: Arnd Bergmann, Steven Rostedt, linux-arch, linux-kernel, Lyra Zhang
On Fri, Sep 16, 2016 at 04:42:44PM +0800, Chunyan Zhang wrote:
> Hi Will and Steven,
>
> May I have a review or an acked-by from you on this patch so that Arnd
> can pick it up.
>
> I have tested this patch on arm qemu, I'm sure it can solve the
> problem described in commit message.
It looks fine to me; we took your equivalent patch for arm64 already, so:
Acked-by: Will Deacon <will.deacon@arm.com>
Will
> On 10 September 2016 at 16:45, Chunyan Zhang <zhang.chunyan@linaro.org> wrote:
> > When debug preempt or preempt tracer is enabled, preempt_count_add/sub()
> > can be traced by function and function graph tracing, and
> > preempt_disable/enable() would call preempt_count_add/sub(), so
> > we should use preempt_disable/enable_notrace in Ftrace subsystem.
> >
> > The function this_cpu_read() started being used by function graph tracing
> > after the commit 345ddcc882d8 ("ftrace: Have set_ftrace_pid use the
> > bitmap like events do"), so it has to use preempt_disable/enable_notrace
> > instead now.
> >
> > Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
> > ---
> > include/asm-generic/percpu.h | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
> > index 4d9f233..70fefec 100644
> > --- a/include/asm-generic/percpu.h
> > +++ b/include/asm-generic/percpu.h
> > @@ -108,9 +108,9 @@ do { \
> > #define this_cpu_generic_read(pcp) \
> > ({ \
> > typeof(pcp) __ret; \
> > - preempt_disable(); \
> > + preempt_disable_notrace(); \
> > __ret = *this_cpu_ptr(&(pcp)); \
> > - preempt_enable(); \
> > + preempt_enable_notrace(); \
> > __ret; \
> > })
> >
> > --
> > 2.7.4
> >
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] percpu: make this_cpu_generic_read notrace
2016-09-16 9:53 ` Will Deacon
@ 2016-09-16 10:08 ` Chunyan Zhang
2016-09-16 13:19 ` Steven Rostedt
2016-09-24 9:18 ` Arnd Bergmann
2 siblings, 0 replies; 6+ messages in thread
From: Chunyan Zhang @ 2016-09-16 10:08 UTC (permalink / raw)
To: Will Deacon
Cc: Arnd Bergmann, Steven Rostedt, linux-arch, linux-kernel, Lyra Zhang
On 16 September 2016 at 17:53, Will Deacon <will.deacon@arm.com> wrote:
> On Fri, Sep 16, 2016 at 04:42:44PM +0800, Chunyan Zhang wrote:
>> Hi Will and Steven,
>>
>> May I have a review or an acked-by from you on this patch so that Arnd
>> can pick it up.
>>
>> I have tested this patch on arm qemu, I'm sure it can solve the
>> problem described in commit message.
>
> It looks fine to me; we took your equivalent patch for arm64 already, so:
Yeah, I saw that.
>
> Acked-by: Will Deacon <will.deacon@arm.com>
Thanks,
Chunyan
>
> Will
>
>> On 10 September 2016 at 16:45, Chunyan Zhang <zhang.chunyan@linaro.org> wrote:
>> > When debug preempt or preempt tracer is enabled, preempt_count_add/sub()
>> > can be traced by function and function graph tracing, and
>> > preempt_disable/enable() would call preempt_count_add/sub(), so
>> > we should use preempt_disable/enable_notrace in Ftrace subsystem.
>> >
>> > The function this_cpu_read() started being used by function graph tracing
>> > after the commit 345ddcc882d8 ("ftrace: Have set_ftrace_pid use the
>> > bitmap like events do"), so it has to use preempt_disable/enable_notrace
>> > instead now.
>> >
>> > Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
>> > ---
>> > include/asm-generic/percpu.h | 4 ++--
>> > 1 file changed, 2 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
>> > index 4d9f233..70fefec 100644
>> > --- a/include/asm-generic/percpu.h
>> > +++ b/include/asm-generic/percpu.h
>> > @@ -108,9 +108,9 @@ do { \
>> > #define this_cpu_generic_read(pcp) \
>> > ({ \
>> > typeof(pcp) __ret; \
>> > - preempt_disable(); \
>> > + preempt_disable_notrace(); \
>> > __ret = *this_cpu_ptr(&(pcp)); \
>> > - preempt_enable(); \
>> > + preempt_enable_notrace(); \
>> > __ret; \
>> > })
>> >
>> > --
>> > 2.7.4
>> >
>>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] percpu: make this_cpu_generic_read notrace
2016-09-16 9:53 ` Will Deacon
2016-09-16 10:08 ` Chunyan Zhang
@ 2016-09-16 13:19 ` Steven Rostedt
2016-09-24 9:18 ` Arnd Bergmann
2 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2016-09-16 13:19 UTC (permalink / raw)
To: Will Deacon
Cc: Chunyan Zhang, Arnd Bergmann, linux-arch, linux-kernel, Lyra Zhang
On Fri, 16 Sep 2016 10:53:09 +0100
Will Deacon <will.deacon@arm.com> wrote:
> On Fri, Sep 16, 2016 at 04:42:44PM +0800, Chunyan Zhang wrote:
> > Hi Will and Steven,
> >
> > May I have a review or an acked-by from you on this patch so that Arnd
> > can pick it up.
> >
> > I have tested this patch on arm qemu, I'm sure it can solve the
> > problem described in commit message.
>
> It looks fine to me; we took your equivalent patch for arm64 already, so:
>
Looks good to me too.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
-- Steve
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] percpu: make this_cpu_generic_read notrace
2016-09-16 9:53 ` Will Deacon
2016-09-16 10:08 ` Chunyan Zhang
2016-09-16 13:19 ` Steven Rostedt
@ 2016-09-24 9:18 ` Arnd Bergmann
2 siblings, 0 replies; 6+ messages in thread
From: Arnd Bergmann @ 2016-09-24 9:18 UTC (permalink / raw)
To: Will Deacon
Cc: Chunyan Zhang, Steven Rostedt, linux-arch, linux-kernel, Lyra Zhang
On Friday, September 16, 2016 10:53:09 AM CEST Will Deacon wrote:
> On Fri, Sep 16, 2016 at 04:42:44PM +0800, Chunyan Zhang wrote:
> > Hi Will and Steven,
> >
> > May I have a review or an acked-by from you on this patch so that Arnd
> > can pick it up.
> >
> > I have tested this patch on arm qemu, I'm sure it can solve the
> > problem described in commit message.
>
> It looks fine to me; we took your equivalent patch for arm64 already, so:
>
> Acked-by: Will Deacon <will.deacon@arm.com>
>
Applied to my asm-generic tree now, sorry for the delay,
Arnd
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-09-24 9:19 UTC | newest]
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2016-09-10 8:45 [PATCH] percpu: make this_cpu_generic_read notrace Chunyan Zhang
2016-09-16 8:42 ` Chunyan Zhang
2016-09-16 9:53 ` Will Deacon
2016-09-16 10:08 ` Chunyan Zhang
2016-09-16 13:19 ` Steven Rostedt
2016-09-24 9:18 ` Arnd Bergmann
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