diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 77641ae6b23fa1f581e833b28af3a8d5a31fb2c3..94e1b28333aed85c62513a6bce62d73bc12f4588 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);
 }