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

To: "Li, Xin" <xin.li@xxxxxxxxx>, "Zhang, Xiantao" <xiantao.zhang@xxxxxxxxx>
Subject: Re: [Xen-devel] Re: [PATCH] Fixed legacy issues when extends number of vcpus > 32
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Mon, 17 Aug 2009 07:50:00 +0100
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Thread-topic: [Xen-devel] Re: [PATCH] Fixed legacy issues when extends number of vcpus > 32
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On 17/08/2009 07:40, "Li, Xin" <xin.li@xxxxxxxxx> wrote:

> I'd agree that as VPID space is per LP, it's not necessary to be globally
> managed.
> If we manage such a big VPID space using a bitmap on each LP, it will require
> quite
> a few memory and be inefficient on VPID allocation and reclaim. So probably we
> can apply the current ASID allocation approach to VPID assuming VPID
> exhaustion
> will be much less.
> On the other side, I can't understand why we need to consider the overflow of
> generations?

Well, the guy who developed it wanted to consider that case. But it is
pretty pointless of course since a 64-bit generation counter will never

Anyhow, your current patch is clearly an improvement on the existing VPID
code, so we'll go with that for the time being.


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