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Re: [Xen-devel] [PATCH 2/6] xen: Add NUMA support to Xen

To: Ryan Harper <ryanh@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH 2/6] xen: Add NUMA support to Xen
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Tue, 2 May 2006 15:17:47 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, Ryan Grimm <grimm@xxxxxxxxxx>
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On 1 May 2006, at 22:57, Ryan Harper wrote:

This patch introduces a per-node layer to the buddy allocator. Xen currently defines the heap as a two-dimensional array, [zone][order]. This patch adds a node layer between zone and order. This allows Xen to hand memory out in the proper zone while preferring local memory allocation, but can fall-back on
non-local to satisfy a zone request.

Loops over every memory chunk structure on the alloc/free paths aren't going to get merged. There's no need for it -- in most cases memory chunks are probably aligned on a MAX_ORDER boundary (or they will be when I reduce MAX_ORDER, which requires me to fix up our Linux swiotlb a bit first). When that isn't the case you can simply reserve guard pages at the start and end of such chunks to avoid cross-chunk merging.

 -- Keir

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