Commit 8f3b90b5 authored Jan 18, 2013 by Mark Rutland Committed by Will Deacon Jan 18, 2013

ARM: perf: remove unnecessary checks for idx < 0



We currently check for hwx->idx < 0 in armpmu_read and armpmu_del
unnecessarily. The only case where hwc->idx < 0 is when armpmu_add
fails, in which case the event's state is set to
PERF_EVENT_STATE_INACTIVE.

The perf core will not attempt to read from an event in
PERF_EVENT_STATE_INACTIVE, and so the check in armpmu_read is
unnecessary. Similarly, if perf core cannot add an event it will not
attempt to delete it, so the WARN_ON in armpmu_del is unnecessary.

This patch removes these two redundant checks.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

parent 76b8a0e4

arch/arm/kernel/perf_event.c

+0 −8

Original line number	Diff line number	Diff line
		@@ -149,12 +149,6 @@ u64 armpmu_event_update(struct perf_event *event)
		static void
		armpmu_read(struct perf_event *event)
		{
		struct hw_perf_event *hwc = &event->hw;

		/* Don't read disabled counters! */
		if (hwc->idx < 0)
		return;

		armpmu_event_update(event);
		}

		@@ -207,8 +201,6 @@ armpmu_del(struct perf_event *event, int flags)
		struct hw_perf_event *hwc = &event->hw;
		int idx = hwc->idx;

		WARN_ON(idx < 0);

		armpmu_stop(event, PERF_EF_UPDATE);
		hw_events->events[idx] = NULL;
		clear_bit(idx, hw_events->used_mask);