* [PATCH] perf: do not set task_ctx pointer in cpuctx if there is no events in the context
@ 2011-10-23 17:10 Gleb Natapov
2011-11-03 7:41 ` Gleb Natapov
2011-11-18 23:32 ` [tip:perf/urgent] perf: Do not set task_ctx pointer in cpuctx if there are " tip-bot for Gleb Natapov
0 siblings, 2 replies; 6+ messages in thread
From: Gleb Natapov @ 2011-10-23 17:10 UTC (permalink / raw)
To: linux-kernel
Cc: Peter Zijlstra, Paul Mackerras, Ingo Molnar,
Arnaldo Carvalho de Melo
Do not set task_ctx pointer during sched_in if there is no
events associated with the context. Otherwise if during task
execution total number of events in the system will become zero
perf_event_context_sched_out() will not be called and cpuctx->task_ctx
will be left with a stale value.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 0f85778..68b13ee 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2172,7 +2172,8 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
perf_event_sched_in(cpuctx, ctx, task);
- cpuctx->task_ctx = ctx;
+ if (ctx->nr_events)
+ cpuctx->task_ctx = ctx;
perf_pmu_enable(ctx->pmu);
perf_ctx_unlock(cpuctx, ctx);
--
Gleb.
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] perf: do not set task_ctx pointer in cpuctx if there is no events in the context
2011-10-23 17:10 [PATCH] perf: do not set task_ctx pointer in cpuctx if there is no events in the context Gleb Natapov
@ 2011-11-03 7:41 ` Gleb Natapov
2011-11-07 13:00 ` Peter Zijlstra
2011-11-18 23:32 ` [tip:perf/urgent] perf: Do not set task_ctx pointer in cpuctx if there are " tip-bot for Gleb Natapov
1 sibling, 1 reply; 6+ messages in thread
From: Gleb Natapov @ 2011-11-03 7:41 UTC (permalink / raw)
To: linux-kernel
Cc: Peter Zijlstra, Paul Mackerras, Ingo Molnar,
Arnaldo Carvalho de Melo
Ingo, Peter can you look into this please.
On Sun, Oct 23, 2011 at 07:10:33PM +0200, Gleb Natapov wrote:
> Do not set task_ctx pointer during sched_in if there is no
> events associated with the context. Otherwise if during task
> execution total number of events in the system will become zero
> perf_event_context_sched_out() will not be called and cpuctx->task_ctx
> will be left with a stale value.
>
> Signed-off-by: Gleb Natapov <gleb@redhat.com>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 0f85778..68b13ee 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -2172,7 +2172,8 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
>
> perf_event_sched_in(cpuctx, ctx, task);
>
> - cpuctx->task_ctx = ctx;
> + if (ctx->nr_events)
> + cpuctx->task_ctx = ctx;
>
> perf_pmu_enable(ctx->pmu);
> perf_ctx_unlock(cpuctx, ctx);
> --
> Gleb.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
Gleb.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] perf: do not set task_ctx pointer in cpuctx if there is no events in the context
2011-11-03 7:41 ` Gleb Natapov
@ 2011-11-07 13:00 ` Peter Zijlstra
2011-11-13 16:06 ` Gleb Natapov
0 siblings, 1 reply; 6+ messages in thread
From: Peter Zijlstra @ 2011-11-07 13:00 UTC (permalink / raw)
To: Gleb Natapov
Cc: linux-kernel, Paul Mackerras, Ingo Molnar,
Arnaldo Carvalho de Melo
On Thu, 2011-11-03 at 09:41 +0200, Gleb Natapov wrote:
> Ingo, Peter can you look into this please.
queued it and the jump_label thing.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] perf: do not set task_ctx pointer in cpuctx if there is no events in the context
2011-11-07 13:00 ` Peter Zijlstra
@ 2011-11-13 16:06 ` Gleb Natapov
2011-11-14 10:50 ` Peter Zijlstra
0 siblings, 1 reply; 6+ messages in thread
From: Gleb Natapov @ 2011-11-13 16:06 UTC (permalink / raw)
To: Peter Zijlstra
Cc: linux-kernel, Paul Mackerras, Ingo Molnar,
Arnaldo Carvalho de Melo
On Mon, Nov 07, 2011 at 02:00:11PM +0100, Peter Zijlstra wrote:
> On Thu, 2011-11-03 at 09:41 +0200, Gleb Natapov wrote:
> > Ingo, Peter can you look into this please.
>
> queued it and the jump_label thing.
I see jump_label thing in tip/perf/core but not this one yet. This is
good because this one needs amendment :) See below.
---
Do not set task_ctx pointer during sched_in if there is no
events associated with the context. Otherwise if during task
execution total number of events in the system will become zero
perf_event_context_sched_out() will not be called and cpuctx->task_ctx
will be left with a stale value. Also perf_event_sched_in() shouldn't try
to schedule task events in this case otherwise cpuctx->task_ctx->is_active
will not be cleared during sched_out and will become incorrect.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d1a1bee..7210657 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2171,9 +2171,10 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
*/
cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
- perf_event_sched_in(cpuctx, ctx, task);
+ if (ctx->nr_events)
+ cpuctx->task_ctx = ctx;
- cpuctx->task_ctx = ctx;
+ perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
perf_pmu_enable(ctx->pmu);
perf_ctx_unlock(cpuctx, ctx);
--
Gleb.
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] perf: do not set task_ctx pointer in cpuctx if there is no events in the context
2011-11-13 16:06 ` Gleb Natapov
@ 2011-11-14 10:50 ` Peter Zijlstra
0 siblings, 0 replies; 6+ messages in thread
From: Peter Zijlstra @ 2011-11-14 10:50 UTC (permalink / raw)
To: Gleb Natapov
Cc: linux-kernel, Paul Mackerras, Ingo Molnar,
Arnaldo Carvalho de Melo
On Sun, 2011-11-13 at 18:06 +0200, Gleb Natapov wrote:
> On Mon, Nov 07, 2011 at 02:00:11PM +0100, Peter Zijlstra wrote:
> > On Thu, 2011-11-03 at 09:41 +0200, Gleb Natapov wrote:
> > > Ingo, Peter can you look into this please.
> >
> > queued it and the jump_label thing.
> I see jump_label thing in tip/perf/core but not this one yet. This is
> good because this one needs amendment :) See below.
Weird ass stuff, because my copy still applies to tip/master. Ingo, wtf
is up?
> ---
>
> Do not set task_ctx pointer during sched_in if there is no
> events associated with the context. Otherwise if during task
> execution total number of events in the system will become zero
> perf_event_context_sched_out() will not be called and cpuctx->task_ctx
> will be left with a stale value. Also perf_event_sched_in() shouldn't try
> to schedule task events in this case otherwise cpuctx->task_ctx->is_active
> will not be cleared during sched_out and will become incorrect.
>
> Signed-off-by: Gleb Natapov <gleb@redhat.com>
--- missing right there
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index d1a1bee..7210657 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -2171,9 +2171,10 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
> */
> cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
>
> - perf_event_sched_in(cpuctx, ctx, task);
> + if (ctx->nr_events)
> + cpuctx->task_ctx = ctx;
>
> - cpuctx->task_ctx = ctx;
> + perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
>
> perf_pmu_enable(ctx->pmu);
> perf_ctx_unlock(cpuctx, ctx);
> --
> Gleb.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [tip:perf/urgent] perf: Do not set task_ctx pointer in cpuctx if there are no events in the context
2011-10-23 17:10 [PATCH] perf: do not set task_ctx pointer in cpuctx if there is no events in the context Gleb Natapov
2011-11-03 7:41 ` Gleb Natapov
@ 2011-11-18 23:32 ` tip-bot for Gleb Natapov
1 sibling, 0 replies; 6+ messages in thread
From: tip-bot for Gleb Natapov @ 2011-11-18 23:32 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, gleb, hpa, mingo, a.p.zijlstra, tglx, mingo
Commit-ID: 1d5f003f5a964711853514b04ddc872eec0fdc7b
Gitweb: http://git.kernel.org/tip/1d5f003f5a964711853514b04ddc872eec0fdc7b
Author: Gleb Natapov <gleb@redhat.com>
AuthorDate: Sun, 23 Oct 2011 19:10:33 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Mon, 14 Nov 2011 13:01:21 +0100
perf: Do not set task_ctx pointer in cpuctx if there are no events in the context
Do not set task_ctx pointer during sched_in if there are no
events associated with the context. Otherwise if during task
execution total number of events in the system will become zero
perf_event_context_sched_out() will not be called and cpuctx->task_ctx
will be left with a stale value.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111023171033.GI17571@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/events/core.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 0e8457d..b0c1186 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2173,7 +2173,8 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
perf_event_sched_in(cpuctx, ctx, task);
- cpuctx->task_ctx = ctx;
+ if (ctx->nr_events)
+ cpuctx->task_ctx = ctx;
perf_pmu_enable(ctx->pmu);
perf_ctx_unlock(cpuctx, ctx);
^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2011-11-18 23:33 UTC | newest]
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2011-10-23 17:10 [PATCH] perf: do not set task_ctx pointer in cpuctx if there is no events in the context Gleb Natapov
2011-11-03 7:41 ` Gleb Natapov
2011-11-07 13:00 ` Peter Zijlstra
2011-11-13 16:06 ` Gleb Natapov
2011-11-14 10:50 ` Peter Zijlstra
2011-11-18 23:32 ` [tip:perf/urgent] perf: Do not set task_ctx pointer in cpuctx if there are " tip-bot for Gleb Natapov
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