perf: Make ctx->is_active and cpuctx->task_ctx consistent
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>
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 935aefd..89b4705 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2329,6 +2329,12 @@
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 @@
return;
ctx_sched_out(ctx, cpuctx, EVENT_ALL);
- cpuctx->task_ctx = NULL;
}
/*
@@ -2712,6 +2717,13 @@
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 @@
* 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);
}