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Fix possible lockup with new scheduler idle balance code.

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Chuck Ebbert 2010-09-22 08:40:20 -04:00
parent 027325ab53
commit 69a476baa9
2 changed files with 44 additions and 0 deletions
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5
kernel.spec
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@ -748,6 +748,7 @@ Patch12570: sched-10-change-nohz-idle-load-balancing-logic-to-push-model.patch
Patch12575: sched-15-update-rq-clock-for-nohz-balanced-cpus.patch
Patch12580: sched-20-fix-rq-clock-synchronization-when-migrating-tasks.patch
Patch12585: sched-25-move-sched_avg_update-to-update_cpu_load.patch
Patch12590: sched-30-sched-fix-nohz-balance-kick.patch
Patch13600: btusb-macbookpro-6-2.patch
Patch13601: btusb-macbookpro-7-1.patch
@ -1388,6 +1389,7 @@ ApplyPatch sched-10-change-nohz-idle-load-balancing-logic-to-push-model.patch
ApplyPatch sched-15-update-rq-clock-for-nohz-balanced-cpus.patch
ApplyPatch sched-20-fix-rq-clock-synchronization-when-migrating-tasks.patch
ApplyPatch sched-25-move-sched_avg_update-to-update_cpu_load.patch
ApplyPatch sched-30-sched-fix-nohz-balance-kick.patch
ApplyPatch btusb-macbookpro-7-1.patch
ApplyPatch btusb-macbookpro-6-2.patch
@ -1978,6 +1980,9 @@ fi
# and build.
%changelog
* Wed Sep 22 2010 Chuck Ebbert <cebbert@redhat.com>
- Fix possible lockup with new scheduler idle balance code.
* Tue Sep 21 2010 Kyle McMartin <kyle@redhat.com>
- Add new btusb ids for MacBookPro from wwoods@.

39
sched-30-sched-fix-nohz-balance-kick.patch Normal file
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@ -0,0 +1,39 @@
From: Suresh Siddha <suresh.b.siddha@intel.com>
Date: Mon, 13 Sep 2010 18:02:21 +0000 (-0700)
Subject: sched: Fix nohz balance kick
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=f6c3f1686e7ec1dd8725a9a3dcb857dfd0c7a5bf
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>
---
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index a171138..db3f674 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);