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>
This commit is contained in:
Gleb Natapov 2011-10-23 19:10:33 +02:00 коммит произвёл Ingo Molnar
Родитель 57d1c0c03c
Коммит 1d5f003f5a
1 изменённых файлов: 2 добавлений и 1 удалений

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@ -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);