From: Ingo Molnar <mingo@kernel.org>
Date: Mon, 5 Sep 2016 10:09:59 +0000 (+0200)
Subject: Merge branch 'perf/urgent' into perf/core, to pick up fixed and resolve conflicts
X-Git-Tag: v4.9-rc1~164^2~13
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=2cc538412a1ca103923ec400a339a5b3833e0280;p=linux.git

Merge branch 'perf/urgent' into perf/core, to pick up fixed and resolve conflicts

 Conflicts:
	kernel/events/core.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

2cc538412a1ca103923ec400a339a5b3833e0280
diff --cc kernel/events/core.c
index 3f07e6cfc1b6,07ac8596a728..dff00c787867
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@@ -3573,15 -3549,18 +3573,23 @@@ static int perf_event_read(struct perf_
  			.group = group,
  			.ret = 0,
  		};
 +
 +		local_cpu = get_cpu();
 +		cpu_to_read = find_cpu_to_read(event, local_cpu);
 +		put_cpu();
 +
- 		ret = smp_call_function_single(cpu_to_read, __perf_event_read, &data, 1);
- 		/* The event must have been read from an online CPU: */
- 		WARN_ON_ONCE(ret);
- 		ret = ret ? : data.ret;
+ 		/*
+ 		 * Purposely ignore the smp_call_function_single() return
+ 		 * value.
+ 		 *
+ 		 * 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);
++		(void)smp_call_function_single(cpu_to_read, __perf_event_read, &data, 1);
+ 		ret = data.ret;
  	} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
  		struct perf_event_context *ctx = event->ctx;
  		unsigned long flags;