Re: [PATCH] Remove RCU abuse in cpu_idle()

From: Zwane Mwaikambo
Date: Mon Dec 13 2004 - 01:25:27 EST


On Sun, 12 Dec 2004, Andrew Morton wrote:

> > void cpu_idle (void)
> > {
> > + int cpu = smp_processor_id();
> > +
> > /* endless idle loop with no priority at all */
>
> This gives me scadzillions of "using smp_procesor_id() in preemptible"
> warnings.
>
> I'll shut that up with _smp_processor_id() but one does wonder what happens
> if we get preempted and `cpu' refers to some other CPU?

The idle thread is special in the sense that it can't get migrated so the
cached values of smp_processor_id are fine.
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