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

[Ryan Harper <ryanh@us.ibm.com>]

* Keir Fraser <Keir.Fraser@cl.cam.ac.uk> [2006-05-02 09:18]:
> 
> 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.

I'll toss page_spans_chunk() and the user in the free path, use some
guard pages and resubmit.  page_to_node still uses the chunk array to
determine which node a struct page_info belongs to, which is used in the
free path.  Is that acceptable?

-- 
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
(512) 838-9253   T/L: 678-9253
ryanh@us.ibm.com