luck/tmp_suning_uos_patched
1
0
Fork 1
Code Issues Pull Requests Packages Projects Releases Wiki Activity

perf/core: Remove WARN from perf_event_read()

Browse Source 
This effectively reverts commit:

  71e7bc2bab ("perf/core: Check return value of the perf_event_read() IPI")

... and puts in a comment explaining why we ignore the return value.

Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Carrillo-Cisneros <davidcc@google.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>
Fixes: 71e7bc2bab ("perf/core: Check return value of the perf_event_read() IPI")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2016-08-30 10:15:03 +02:00 committed by Ingo Molnar
parent c6935931c1
commit 5876314875
1 changed files with 12 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
kernel/events/core.c
View File

@ -3549,10 +3549,18 @@ static int perf_event_read(struct perf_event *event, bool group)
.group = group, .group = group,
.ret = 0, .ret = 0,
}; };
ret = smp_call_function_single(event->oncpu, __perf_event_read, &data, 1); /*
/* The event must have been read from an online CPU: */ * Purposely ignore the smp_call_function_single() return
WARN_ON_ONCE(ret); * value.
ret = ret ? : data.ret; *
* If event->oncpu isn't a valid CPU it means the event got
* scheduled out and that will have updated the event count.
*
* Therefore, either way, we'll have an up-to-date event count
* after this.
*/
(void)smp_call_function_single(event->oncpu, __perf_event_read, &data, 1);
ret = data.ret;
} else if (event->state == PERF_EVENT_STATE_INACTIVE) { } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
struct perf_event_context *ctx = event->ctx; struct perf_event_context *ctx = event->ctx;
unsigned long flags; unsigned long flags;