Re: [PATCH 1 of 6] x86, UV: smp_processor_id in a preemptable region

From: Cliff Wickman
Date: Wed Jun 15 2011 - 14:56:57 EST


On Wed, Jun 15, 2011 at 10:21:42AM -0700, H. Peter Anvin wrote:
> On 06/15/2011 09:40 AM, Cliff Wickman wrote:
> >
> > So would you say I should really widen the scope of the non-preemptible
> > region to include everything done with the results of that call to
> > smp_processor_id()?
> > Which in this case is the call to parse_tunables_write().
> > Like this:
> >
> > preempt_disable();
> > bcp = &per_cpu(bau_control, smp_processor_id());
> >
> > ret = parse_tunables_write(bcp, instr, count);
> > preempt_enable_no_resched();
> >
>
> Funny enough, this is such a common pattern that we have helpers for it.
> We call this get_cpu() ... put_cpu().
>
> -hpa

OK thanks. I'll use them.


I'll fix that patch (1 of 8) and refresh/resend the whole series after a
little time to allow for more reviews of the others.

-Cliff
--
Cliff Wickman
SGI
cpw@xxxxxxx
(651) 683-3824
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