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Re: [Xen-devel] RFC: large system support - 128 CPUs

To: Tim Deegan <Tim.Deegan@xxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] RFC: large system support - 128 CPUs
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Wed, 13 Aug 2008 09:26:26 +0100
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Bill Burns <bburns@xxxxxxxxxx>
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On 13/8/08 09:22, "Tim Deegan" <Tim.Deegan@xxxxxxxxxx> 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.

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.

 -- Keir

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