* [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] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 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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