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ARM: 6902/1: perf: Remove erroneous check on active_events 

When initialising a PMU, there is a check to protect against races with
other CPUs filling all of the available event slots. Since armpmu_add
checks that an event can be scheduled, we do not need to do this at
initialisation time. Furthermore the current code is broken because it
assumes that atomic_inc_not_zero will unconditionally increment
active_counts and then tries to decrement it again on failure.

This patch removes the broken, redundant code.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Mark Rutland 2011-05-17 09:15:38 +01:00 committed by Russell King
parent 31bee4cf0e
commit 57ce9bb39b
1 changed files with 0 additions and 5 deletions
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5
arch/arm/kernel/perf_event.c
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@ -560,11 +560,6 @@ static int armpmu_event_init(struct perf_event *event)
event->destroy = hw_perf_event_destroy;
if (!atomic_inc_not_zero(&active_events)) {
if (atomic_read(&active_events) > armpmu->num_events) {
atomic_dec(&active_events);
return -ENOSPC;
}
mutex_lock(&pmu_reserve_mutex);
if (atomic_read(&active_events) == 0) {
err = armpmu_reserve_hardware();