softlockup: fix watchdog task wakeup frequency

Updating the timestamp more often is pointless as we print the warnings
only if we exceed the threshold.  And the check for hung tasks relies on
the last timestamp, so it will keep working correctly, too.

Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 97977ecc317164ab866dcb8f48495499d03892f7..d53ab702a7dbaaf9304eb9e7137f5a66138180e5 100644 (file)
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -130,8 +130,11 @@ void softlockup_tick(void)
 
        now = get_timestamp(this_cpu);
 
-       /* Wake up the high-prio watchdog task every second: */
-       if (now > (touch_timestamp + 1))
+       /*
+        * Wake up the high-prio watchdog task twice per
+        * threshold timespan.
+        */
+       if (now > touch_timestamp + softlockup_thresh/2)
                wake_up_process(per_cpu(watchdog_task, this_cpu));
 
        /* Warn about unreasonable delays: */