perf: Update a stale comment

Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Michael Neuling <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: [email protected]
Cc: Vince Weaver <[email protected]>
Cc: Victor Kaplansky <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Anton Blanchard <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index c52a32fa5592c60ba8ebd26c58a73c2fe7e2e69e..e8b168af135ba3ec7d72c780746ce02f051be2e3 100644 (file)
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -85,8 +85,8 @@ again:
        rb->user_page->data_head = head;
 
        /*
-        * Now check if we missed an update, rely on the (compiler)
-        * barrier in atomic_dec_and_test() to re-read rb->head.
+        * Now check if we missed an update -- rely on previous implied
+        * compiler barriers to force a re-read.
         */
        if (unlikely(head != local_read(&rb->head))) {
                local_inc(&rb->nest);