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[Xen-devel] Re: [PATCH] Fixed legacy issues when extends number of vcpus

To: "Zhang, Xiantao" <xiantao.zhang@xxxxxxxxx>
Subject: [Xen-devel] Re: [PATCH] Fixed legacy issues when extends number of vcpus > 32
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Sun, 16 Aug 2009 10:55:47 +0100
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On 16/08/2009 09:55, "Zhang, Xiantao" <xiantao.zhang@xxxxxxxxx> wrote:

> Keir Fraser wrote:
>> Let me think about these. For patch 1 I think we can perhaps do more
>> work in the loop which matches vlapic identifiers, and thus avoid
>> needing a "temporary cpumask" to remember matches. For patch 2 I've
>> been intending to throw away the VMX VPID logic and share the SVM
>> logic, as it flushes TLBs no more than the VMX logic and doesn't
>> suffer the same problems with VPID/ASID exhaustion.
> We have 2^16 vpids after removing the limit, so it should support 65535 vcpus
> runing concurrently in a system, so we don't need to consider the exhaustion
> case from this point of view ?

Why have two sets of logic when one is superior to the other? It doesn't
make sense. I'll take a look at your patch and apply it for now, however.

 -- Keir

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