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| author | Peter Zijlstra <peterz@infradead.org> | 2016-02-24 17:45:48 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-02-25 07:43:34 (GMT) |
| commit | 7fce250915efca0f8f51dddee3ae89bf30d86ca5 (patch) | |
| tree | 06c281db7bfe6140b3eca7102c92f3b7692193e6 /kernel | |
| parent | 3cbaa59069677920186dcf502632ca1df4329f80 (diff) | |
| download | linux-7fce250915efca0f8f51dddee3ae89bf30d86ca5.tar.xz | |
perf: Fix scaling vs. perf_event_enable_on_exec()
The recent commit 3e349507d12d ("perf: Fix perf_enable_on_exec() event
scheduling") caused this by moving task_ctx_sched_out() from before
__perf_event_mask_enable() to after it.
The overlooked consequence of that change is that task_ctx_sched_out()
would update the ctx time fields, and now __perf_event_mask_enable()
uses stale time.
In order to fix this, explicitly stop our context's time before
enabling the event(s).
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dvyukov@google.com
Cc: eranian@google.com
Cc: panand@redhat.com
Cc: sasha.levin@oracle.com
Cc: vince@deater.net
Fixes: 3e349507d12d ("perf: Fix perf_enable_on_exec() event scheduling")
Link: http://lkml.kernel.org/r/20160224174948.159242158@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 75bde93..d003088 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3143,6 +3143,7 @@ static void perf_event_enable_on_exec(int ctxn) cpuctx = __get_cpu_context(ctx); perf_ctx_lock(cpuctx, ctx); + ctx_sched_out(ctx, cpuctx, EVENT_TIME); list_for_each_entry(event, &ctx->event_list, event_entry) enabled |= event_enable_on_exec(event, ctx); |