Re: idle issues running sembench on 128 cpus

[Thomas Gleixner]

On Thu, 5 May 2011, Thomas Gleixner wrote:
> On Thu, 5 May 2011, Andi Kleen wrote:
> > > No, it does not even need refcounting. We can access it outside of the
> > 
> > Ok.
> > 
> > > lock as this is atomic context called on the cpu which is about to go
> > > idle and therefor the device cannot go away. Easy and straightforward
> > > fix.
> > 
> > Ok. Patch appended. Looks good?
> 
> Mostly. See below.
>  
> > BTW why must the lock be irqsave?
> 
> Good question. Probably safety frist paranoia :)
> 
> Indeed that code should only be called from irq disabled regions, so
> we could avoid the irqsave there. Otherwise that needs to be irqsave
> for obvious reasons.

Just looked through all the call sites. Both intel_idle and
processor_idle notify ENTER with interrups disabled, but EXIT with
interrupts enabled. So when we want to remove irqsave from the
spinlock that needs to be fixed as well.

Thanks,

        tglx
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