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authorAmit K. Arora <aarora@linux.vnet.ibm.com>2010-05-25 18:53:46 +0530
committerIngo Molnar <mingo@elte.hu>2010-05-31 08:37:44 +0200
commit54e88fad223c4e1d94289611a90c7fe3ebe5631b (patch)
treec9c9f27bf4e1e9851ee75145960607f194b3313b
parent67a3e12b05e055c0415c556a315a3d3eb637e29e (diff)
downloadop-kernel-dev-54e88fad223c4e1d94289611a90c7fe3ebe5631b.zip
op-kernel-dev-54e88fad223c4e1d94289611a90c7fe3ebe5631b.tar.gz
sched: Make sure timers have migrated before killing the migration_thread
Problem: In a stress test where some heavy tests were running along with regular CPU offlining and onlining, a hang was observed. The system seems to be hung at a point where migration_call() tries to kill the migration_thread of the dying CPU, which just got moved to the current CPU. This migration thread does not get a chance to run (and die) since rt_throttled is set to 1 on current, and it doesn't get cleared as the hrtimer which is supposed to reset the rt bandwidth (sched_rt_period_timer) is tied to the CPU which we just marked dead! Solution: This patch pushes the killing of migration thread to "CPU_POST_DEAD" event. By then all the timers (including sched_rt_period_timer) should have got migrated (along with other callbacks). Signed-off-by: Amit Arora <aarora@in.ibm.com> Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <20100525132346.GA14986@amitarora.in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/stop_machine.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index b4e7431..70f8d90 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -321,7 +321,7 @@ static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb,
#ifdef CONFIG_HOTPLUG_CPU
case CPU_UP_CANCELED:
- case CPU_DEAD:
+ case CPU_POST_DEAD:
{
struct cpu_stop_work *work;
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