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| author | Ingo Molnar <mingo@elte.hu> | 2008-04-25 00:25:08 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-04-25 00:25:08 +0200 |
| commit | 126e01bf92dfc5f0ba91e88be02c473e1506d7d9 (patch) | |
| tree | fe883f07319193bfbec244becc43e64a22e64f95 /kernel/time/tick-sched.c | |
| parent | seqlock: livelock fix (diff) | |
| download | linux-126e01bf92dfc5f0ba91e88be02c473e1506d7d9.tar.xz linux-126e01bf92dfc5f0ba91e88be02c473e1506d7d9.zip | |
softlockup: fix NOHZ wakeup
David Miller reported:
|--------------->
the following commit:
| commit 27ec4407790d075c325e1f4da0a19c56953cce23
| Author: Ingo Molnar <mingo@elte.hu>
| Date: Thu Feb 28 21:00:21 2008 +0100
|
| sched: make cpu_clock() globally synchronous
|
| Alexey Zaytsev reported (and bisected) that the introduction of
| cpu_clock() in printk made the timestamps jump back and forth.
|
| Make cpu_clock() more reliable while still keeping it fast when it's
| called frequently.
|
| Signed-off-by: Ingo Molnar <mingo@elte.hu>
causes watchdog triggers when a cpu exits NOHZ state when it has been
there for >= the soft lockup threshold, for example here are some
messages from a 128 cpu Niagara2 box:
[ 168.106406] BUG: soft lockup - CPU#11 stuck for 128s! [dd:3239]
[ 168.989592] BUG: soft lockup - CPU#21 stuck for 86s! [swapper:0]
[ 168.999587] BUG: soft lockup - CPU#29 stuck for 91s! [make:4511]
[ 168.999615] BUG: soft lockup - CPU#2 stuck for 85s! [swapper:0]
[ 169.020514] BUG: soft lockup - CPU#37 stuck for 91s! [swapper:0]
[ 169.020514] BUG: soft lockup - CPU#45 stuck for 91s! [sh:4515]
[ 169.020515] BUG: soft lockup - CPU#69 stuck for 92s! [swapper:0]
[ 169.020515] BUG: soft lockup - CPU#77 stuck for 92s! [swapper:0]
[ 169.020515] BUG: soft lockup - CPU#61 stuck for 92s! [swapper:0]
[ 169.112554] BUG: soft lockup - CPU#85 stuck for 92s! [swapper:0]
[ 169.112554] BUG: soft lockup - CPU#101 stuck for 92s! [swapper:0]
[ 169.112554] BUG: soft lockup - CPU#109 stuck for 92s! [swapper:0]
[ 169.112554] BUG: soft lockup - CPU#117 stuck for 92s! [swapper:0]
[ 169.171483] BUG: soft lockup - CPU#40 stuck for 80s! [dd:3239]
[ 169.331483] BUG: soft lockup - CPU#13 stuck for 86s! [swapper:0]
[ 169.351500] BUG: soft lockup - CPU#43 stuck for 101s! [dd:3239]
[ 169.531482] BUG: soft lockup - CPU#9 stuck for 129s! [mkdir:4565]
[ 169.595754] BUG: soft lockup - CPU#20 stuck for 93s! [swapper:0]
[ 169.626787] BUG: soft lockup - CPU#52 stuck for 93s! [swapper:0]
[ 169.626787] BUG: soft lockup - CPU#84 stuck for 92s! [swapper:0]
[ 169.636812] BUG: soft lockup - CPU#116 stuck for 94s! [swapper:0]
It's simple enough to trigger this by doing a 10 minute sleep after a
fresh bootup then starting a parallel kernel build.
I suspect this might be reintroducing a problem we've had and fixed
before, see the thread:
http://marc.info/?l=linux-kernel&m=119546414004065&w=2
<---------------|
touch the softlockup watchdog when exiting NOHZ state - we are
obviously not locked up.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/time/tick-sched.c')
| -rw-r--r-- | kernel/time/tick-sched.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index d358d4e3a958..b854a895591e 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -393,6 +393,7 @@ void tick_nohz_restart_sched_tick(void) sub_preempt_count(HARDIRQ_OFFSET); } + touch_softlockup_watchdog(); /* * Cancel the scheduled timer and restore the tick */ |