kernel/watchdog.c: add comment to watchdog() exit path

Revelation from Peter.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@tglx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index a01cb03b045a..df30ee08bdd4 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -349,6 +349,10 @@ static int watchdog(void *unused)
 
                 set_current_state(TASK_INTERRUPTIBLE);
         }
+        /*
+         * Drop the policy/priority elevation during thread exit to avoid a
+         * scheduling latency spike.
+         */
         __set_current_state(TASK_RUNNING);
         sched_setscheduler(current, SCHED_NORMAL, &param);
         return 0;