Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH] keep rd->online and cpu_online_map in sync | Date | Mon, 10 Mar 2008 23:03:27 +0100 |
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On Monday, 10 of March 2008, Suresh Siddha wrote: > On Mon, Mar 10, 2008 at 09:39:34AM -0400, Gregory Haskins wrote: > > keep rd->online and cpu_online_map in sync > > > > It is possible to allow the root-domain cache of online cpus to > > become out of sync with the global cpu_online_map. This is because we > > currently trigger removal of cpus too early in the notifier chain. > > Other DOWN_PREPARE handlers may in fact run and reconfigure the > > root-domain topology, thereby stomping on our own offline handling. > > > > The end result is that rd->online may become out of sync with > > cpu_online_map, which results in potential task misrouting. > > > > So change the offline handling to be more tightly coupled with the > > global offline process by triggering on CPU_DYING intead of > > CPU_DOWN_PREPARE. > > > > Signed-off-by: Gregory Haskins <ghaskins@novell.com> > > --- > > > > kernel/sched.c | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > diff --git a/kernel/sched.c b/kernel/sched.c > > index 52b9867..a616fa1 100644 > > --- a/kernel/sched.c > > +++ b/kernel/sched.c > > @@ -5881,7 +5881,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) > > spin_unlock_irq(&rq->lock); > > break; > > > > - case CPU_DOWN_PREPARE: > > + case CPU_DYING: > > Don't we need to take care of CPU_DYING_FROZEN aswell?
Well, I'd say we do.
> > /* Update our root-domain */ > > rq = cpu_rq(cpu); > > spin_lock_irqsave(&rq->lock, flags); > >
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