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perf: Make ctx->is_active and cpuctx->task_ctx consistent

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For no apparent reason and to great confusion the rules for
ctx->is_active and cpuctx->task_ctx are different. This means that its
not always possible to find all active (task) contexts.

Fix this such that if ctx->is_active gets set, we also set (or verify)
cpuctx->task_ctx.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2016-01-08 11:39:10 +01:00 committed by Ingo Molnar
parent 25432ae96a
commit 63e30d3e52
1 changed files with 14 additions and 7 deletions
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21
kernel/events/core.c
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@ -2329,6 +2329,12 @@ static void ctx_sched_out(struct perf_event_context *ctx,
lockdep_assert_held(&ctx->lock);
ctx->is_active &= ~event_type;
if (ctx->task) {
WARN_ON_ONCE(cpuctx->task_ctx != ctx);
if (!ctx->is_active)
cpuctx->task_ctx = NULL;
}
if (likely(!ctx->nr_events))
return;
@ -2629,7 +2635,6 @@ static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
return;
ctx_sched_out(ctx, cpuctx, EVENT_ALL);
cpuctx->task_ctx = NULL;
}
/*
@ -2712,6 +2717,13 @@ ctx_sched_in(struct perf_event_context *ctx,
lockdep_assert_held(&ctx->lock);
ctx->is_active |= event_type;
if (ctx->task) {
if (!is_active)
cpuctx->task_ctx = ctx;
else
WARN_ON_ONCE(cpuctx->task_ctx != ctx);
}
if (likely(!ctx->nr_events))
return;
@ -2756,12 +2768,7 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
* cpu flexible, task flexible.
*/
cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
if (ctx->nr_events)
cpuctx->task_ctx = ctx;
perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
perf_event_sched_in(cpuctx, ctx, task);
perf_pmu_enable(ctx->pmu);
perf_ctx_unlock(cpuctx, ctx);
}