Re: RFC: large system support - 128 CPUs

[Bill Burns <bburns@redhat.com>]

Keir Fraser wrote:
> On 13/8/08 09:22, "Tim Deegan" <Tim.Deegan@citrix.com> wrote:
> 
>> At 09:21 +0100 on 13 Aug (1218619274), Jan Beulich wrote:
>>> Both seem to be hacks to get to 128 CPUs, without consideration of how
>>> to go beyond that
>> I think the shadow_page_info one is a general fix for my implicit
>> assumption that sizeof(cpumask_t) == sizeof (long).
> 
> Do some fields after the cpumask need to line up in both structures? Placing
> a dummy cpumask in the shadow_page structure might make most sense.

Yes, there is a check that a field of page_info and a
field of the shadow_page_info are at the same offset.
Both compile time checks are in private.h

> 
> For the other one I'll have to think a bit. The need for GDT entries per CPU
> currently obviously means scaling much past a few hundred CPUs is going to
> be difficult.

Yes, would like something better here. And as I said, we
don't know yet that just adding the additional page solves
anything.

 Bill


> 
>  -- Keir
> 
>