On Wed, 2011-02-09 at 17:14 +1100, Benjamin Herrenschmidt wrote: > On Mon, 2011-02-07 at 14:54 +0100, Peter Zijlstra wrote: > > On Mon, 2011-02-07 at 10:26 +1100, Benjamin Herrenschmidt wrote: > > > You missed: > > > > > > diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c > > > index 9813605..467d122 100644 > > > --- a/arch/powerpc/kernel/smp.c > > > +++ b/arch/powerpc/kernel/smp.c > > > @@ -98,6 +98,7 @@ void smp_message_recv(int msg) > > > break; > > > case PPC_MSG_RESCHEDULE: > > > /* we notice need_resched on exit */ > > > + scheduler_ipi(); > > > break; > > > case PPC_MSG_CALL_FUNC_SINGLE: > > > generic_smp_call_function_single_interrupt(); > > > > > > Fold that in and add: > > > > > > Acked-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> > > > > Thanks Ben! > > BTW. I we lurking at some of our CPU hotplug code and I think I cannot > totally guarantee that this won't be called on an offline CPU. If that's > a problem, you may want to add a test for that. > > IE. The call function IPIs are normally not going to be sent to an > offlined CPU, and stop_machine should be a good enough fence here, but > we do abuse reschedule for a number of things (including in some case > to wake up a sleeping CPU that was pseudo-offlined :-) Hmm, I _think_ that should all work out nicely, but we'll see, if when this stuff hits the tree powerpc machines start falling over we'd better put that check in ;-) Meanwhile I'm going to preserve this comment in the changelog of this patch so we don't forget.
