Re: [PATCH UPDATED#3 04/16] x86: setup_local_APIC() must always becalled with preemption disabled

From: Thomas Gleixner
Date: Fri Dec 10 2010 - 06:10:50 EST


On Fri, 10 Dec 2010, Tejun Heo wrote:

> On 12/09/2010 10:56 PM, Thomas Gleixner wrote:
> > On Thu, 9 Dec 2010, Tejun Heo wrote:
> >
> >> setup_local_APIC() is used to setup local APIC early during CPU
> >> initialization and already assumes that preemption is disabled on
> >> entry. However, The function unnecessarily disables and enables
> >> preemption and uses smp_processor_id() multiple times in and out of
> >> the nested preemption disabled section. This gives the wrong
> >> impression that the function might be able to handle being called with
> >> preemption enabled and/or migrated to another processor in the middle.
> >>
> >> Make it clear that the function is always called with preemption
> >> disabled, drop the confusing preemption disable block and call
> >> smp_processor_id() once at the beginning of the function.
> >
> > AFAICT, this one is completely unrelated to that NUMA cleanup, right ?
> >
> > So this can be applied independent and should never have been part of
> > that NUMA series in the first place.
>
> Originally, it was a trivial prep patch. Anyways, I'll push it
> to the top of the series so that it can be taken separately.

I pick it up from mail.

Thanks,

tglx
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