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| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2010-09-13 11:02:21 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-09-21 13:50:50 +0200 |
| commit | f6c3f1686e7ec1dd8725a9a3dcb857dfd0c7a5bf (patch) | |
| tree | fb0179d1f071dbb857e0ab7f2aace4579deb62c1 /kernel/sched_fair.c | |
| parent | e75e863dd5c7d96b91ebbd241da5328fc38a78cc (diff) | |
| download | lwn-f6c3f1686e7ec1dd8725a9a3dcb857dfd0c7a5bf.tar.gz lwn-f6c3f1686e7ec1dd8725a9a3dcb857dfd0c7a5bf.zip | |
sched: Fix nohz balance kick
There's a situation where the nohz balancer will try to wake itself:
cpu-x is idle which is also ilb_cpu
got a scheduler tick during idle
and the nohz_kick_needed() in trigger_load_balance() checks for
rq_x->nr_running which might not be zero (because of someone waking a
task on this rq etc) and this leads to the situation of the cpu-x
sending a kick to itself.
And this can cause a lockup.
Avoid this by not marking ourself eligible for kicking.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1284400941.2684.19.camel@sbsiddha-MOBL3.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_fair.c')
| -rw-r--r-- | kernel/sched_fair.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index a171138a9402..db3f674ca49d 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -3630,7 +3630,7 @@ static inline int nohz_kick_needed(struct rq *rq, int cpu) if (time_before(now, nohz.next_balance)) return 0; - if (!rq->nr_running) + if (rq->idle_at_tick) return 0; first_pick_cpu = atomic_read(&nohz.first_pick_cpu); |