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authorPeter Zijlstra <peterz@infradead.org>2016-02-24 17:45:48 (GMT)
committerIngo Molnar <mingo@kernel.org>2016-02-25 07:43:34 (GMT)
commit7fce250915efca0f8f51dddee3ae89bf30d86ca5 (patch)
tree06c281db7bfe6140b3eca7102c92f3b7692193e6 /kernel
parent3cbaa59069677920186dcf502632ca1df4329f80 (diff)
downloadlinux-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.c1
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);