Re: Problem with cpu_rest() change

Kumar Gala
2005-01-26T05:45:52Z

Will these changes cause us to back out the patch already made to
arch/ppc/kernel/idle.c for systems that did not support powersavings?

- kumar

On Jan 25, 2005, at 5:49 PM, Benjamin Herrenschmidt wrote:

> On Tue, 2005-01-25 at 10:01 +0100, Ingo Molnar wrote:
>
> > it can be bad for the idle task to hold the BKL and to have
> preemption
> > enabled - in such a situation the scheduler will get confused if an
> > interrupt triggers a forced preemption in that small window. But
> it's
> > not necessary to keep IRQs disabled after the BKL has been dropped.
> In
> > fact i think IRQ-disabling doesnt have to be done at all, the patch
> > below ought to solve this scenario equally well, and should solve
> the
> > PPC side-effects too.
> >
> > Tested ontop of 2.6.11-rc2 on x86 PREEMPT+SMP and PREEMPT+!SMP (which
> > IIRC were the config variants that triggered the original problem),
> on
> > an SMP and on a UP system.
>
> Excellent, thanks.
>
> Ben.
>
>
>
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