Re: [PATCH -v2 5/5] x86: use dmi check to treat disabled cpus ashotplug cpus.

From: Suresh Siddha
Date: Wed Jan 13 2010 - 17:50:34 EST


On Wed, 2010-01-13 at 14:36 -0800, H. Peter Anvin wrote:
> On 01/13/2010 02:29 PM, Suresh Siddha wrote:
> >>
> >> Well, that *is* working around broken code, in this case the broken code
> >> is the percpu allocation strategy.
> >
> > Andi, Recently percpu folks changed the per-cpu static first chunk to
> > PMD SIZE right. I think that is what causing all this issue.
> >
>
> Please don't tell me we're allocating 2 MB per CPU and throwing away
> most of it...

Looking at the percpu code, they do seem to free the unused memory in
that hole.

Yinghai, what are the configurations that need MB's of per cpu area?

thanks,
suresh

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