perf: Convert perf_event to local_t
Since now all modification to event->count (and ->prev_count
and ->period_left) are local to a cpu, change then to local64_t so we
avoid the LOCK'ed ops.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/sh/kernel/perf_event.c b/arch/sh/kernel/perf_event.c
index 81b6de4..7a3dc35 100644
--- a/arch/sh/kernel/perf_event.c
+++ b/arch/sh/kernel/perf_event.c
@@ -185,10 +185,10 @@
* this is the simplest approach for maintaining consistency.
*/
again:
- prev_raw_count = atomic64_read(&hwc->prev_count);
+ prev_raw_count = local64_read(&hwc->prev_count);
new_raw_count = sh_pmu->read(idx);
- if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count,
+ if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
new_raw_count) != prev_raw_count)
goto again;
@@ -203,7 +203,7 @@
delta = (new_raw_count << shift) - (prev_raw_count << shift);
delta >>= shift;
- atomic64_add(delta, &event->count);
+ local64_add(delta, &event->count);
}
static void sh_pmu_disable(struct perf_event *event)