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xen-devel
[Xen-devel] Re: Memory fragmentation, order>0 allocation, and 4.0 dynami
To: |
Keir Fraser <Keir.Fraser@xxxxxxxxxxxxx> |
Subject: |
[Xen-devel] Re: Memory fragmentation, order>0 allocation, and 4.0 dynamic RAM optimization features |
From: |
Tim Deegan <Tim.Deegan@xxxxxxxxxx> |
Date: |
Tue, 9 Feb 2010 10:50:10 +0000 |
Cc: |
Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, Ian Pratt <Ian.Pratt@xxxxxxxxxxxxx>, Jan Beulich <JBeulich@xxxxxxxxxx>, Patrick Colp <pjcolp@xxxxxxxxx>, Milos <gm281@xxxxxxxxx>, Grzegorz, Andrew Peace <Andrew.Peace@xxxxxxxxxxxxx> |
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Tue, 09 Feb 2010 02:50:26 -0800 |
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Mutt/1.5.18 (2008-05-17) |
At 19:11 +0000 on 08 Feb (1265656284), Keir Fraser wrote:
> I think everything but the shadow use of order-2 allocations is pretty easy
> to fix; just a case of logically carving up the multi-page structures.
>
> I'm not sure, but suspect that fragmenting the shadow allocations may
> require extra book-keeping space in the page_info structure, for example.
I think it can be done without expanding page_info, but it involves
pretty invasive changes to all the parts of the shadow code that deal
with guest<->shadow mappings and with iterating across shadows.
As I said in response to an earlier email, I think the right thing to do
here is to move pretty much all allocation in Xen to superpage
granularity (and not just because it makes this issue go away!).
Tim
--
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, XenServer Engineering
Citrix Systems UK Ltd. (Company #02937203, SL9 0BG)
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