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Re: [Xen-devel] [PATCH] Fix domheap structure allocation when NUMA=on

To: Jan Beulich <jbeulich@xxxxxxxxxx>, Xiaowei Yang <xiaowei.yang@xxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Fix domheap structure allocation when NUMA=on
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Fri, 20 Mar 2009 08:56:18 +0000
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On 20/03/2009 08:47, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:

> virt_to_mfn(DIRECTMAP_VIRT_END - 1) is equal to
> Depending on whether DIRECTMAP_VIRT_END is the last byte or the first
> following byte. Using "- 1" avoids such a dependency.
>> virt_to_mfn(DIRECTMAP_VIRT_END - PAGE_SIZE). Why +1? We use '<=' here.
> Because on the left side of the comparison we also calculate the first
> following mfn, not the last included one.

Since DIRECTMAP_VIRT_END is always the following byte not the last byte, it
sounds like you think the page_alloc.c chunk is not needed at all. I'll just
check in the header fix for now.

 -- Keir

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