diff options
| author | Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> | 2009-12-09 04:30:36 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-12-09 09:56:27 +0100 |
| commit | ec89a06fd4e12301f11ab039ee07d2353a18addc (patch) | |
| tree | 507d33bda6504dd8422b9952156d338b0200fb2b /kernel | |
| parent | perf_event: Allocate children's perf_event_ctxp at the right time (diff) | |
| download | linux-ec89a06fd4e12301f11ab039ee07d2353a18addc.tar.xz linux-ec89a06fd4e12301f11ab039ee07d2353a18addc.zip | |
perf_event: Cleanup for cpu_clock_perf_event_update()
Using atomic64_xchg() instead of atomic64_read() and
atomic64_set().
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <4B1F19DC.90204@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/perf_event.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 77641ae6b23f..94e1b28333ae 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -4079,8 +4079,7 @@ static void cpu_clock_perf_event_update(struct perf_event *event) u64 now; now = cpu_clock(cpu); - prev = atomic64_read(&event->hw.prev_count); - atomic64_set(&event->hw.prev_count, now); + prev = atomic64_xchg(&event->hw.prev_count, now); atomic64_add(now - prev, &event->count); } |