Messages in this thread | | | Subject | Re: [PATCH] Make sure timers have migrated before killing migration_thread | From | Peter Zijlstra <> | Date | Tue, 25 May 2010 13:31:35 +0200 |
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On Mon, 2010-05-24 at 15:29 +0530, Amit K. Arora wrote: > > Thus, since above race can never happen, is there any other issue with > this patch ?
It doesn't seem to apply nicely...
> > Signed-off-by: Amit Arora <aarora@in.ibm.com> > Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> > --- > diff -Nuarp linux-2.6.34.org/kernel/sched.c linux-2.6.34/kernel/sched.c > --- linux-2.6.34.org/kernel/sched.c 2010-05-18 22:56:21.000000000 -0700 > +++ linux-2.6.34/kernel/sched.c 2010-05-18 22:58:31.000000000 -0700 > @@ -5942,14 +5942,26 @@ migration_call(struct notifier_block *nf > cpu_rq(cpu)->migration_thread = NULL; > break; > > + case CPU_POST_DEAD: > + /* > + * Bring the migration thread down in CPU_POST_DEAD event, > + * since the timers should have got migrated by now and thus > + * we should not see a deadlock between trying to kill the > + * migration thread and the sched_rt_period_timer. > + */ > + cpuset_lock(); > + rq = cpu_rq(cpu); > + kthread_stop(rq->migration_thread); > + put_task_struct(rq->migration_thread); > + rq->migration_thread = NULL; > + cpuset_unlock(); > + break; > + > case CPU_DEAD: > case CPU_DEAD_FROZEN: > cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */ > migrate_live_tasks(cpu); > rq = cpu_rq(cpu); > - kthread_stop(rq->migration_thread); > - put_task_struct(rq->migration_thread); > - rq->migration_thread = NULL; > /* Idle task back to normal (off runqueue, low prio) */ > raw_spin_lock_irq(&rq->lock); > update_rq_clock(rq); > >
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