Commit 7f0ec325 authored Sep 05, 2017 by Peter Zijlstra Committed by Ingo Molnar Oct 27, 2017

perf/core: Remove wrong barrier



The barrier and comment make no sense:

 - if what the barrier says is true, it should be wmb() but that
   should then be part of the arch driver, not the generic code.

 - if it is an SMP barrier, there must be a matching barrier, and
   there isn't one.

So kill it.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 8ca2bd41

kernel/events/core.c

+0 −5

Original line number	Original line	Diff line number	Diff line
	@@ -2097,11 +2097,6 @@ event_sched_in(struct perf_event *event,
	event->hw.interrupts = 0;		event->hw.interrupts = 0;
	}		}

	/*
	* The new state must be visible before we turn it on in the hardware:
	*/
	smp_wmb();

	perf_pmu_disable(event->pmu);		perf_pmu_disable(event->pmu);

	perf_set_shadow_time(event, ctx, tstamp);		perf_set_shadow_time(event, ctx, tstamp);

Admin message