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Date: Sat, 23 Feb 2008 00:05:57 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       linux-kernel@vger.kernel.org, linux-mm@kvack.org,
       netdev@vger.kernel.org, trond.myklebust@fys.uio.no
Subject: Re: [PATCH 08/28] mm: system wide ALLOC_NO_WATERMARK
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	<20080220150306.297640000@chello.nl>
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On Wed, 20 Feb 2008 15:46:18 +0100 Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:

> Change ALLOC_NO_WATERMARK page allocation such that the reserves are system
> wide - which they are per setup_per_zone_pages_min(), when we scrape the
> barrel, do it properly.
> 

The changelog is fairly incomprehensible.

>  mm/page_alloc.c |    6 ++++++
>  1 file changed, 6 insertions(+)
> 
> Index: linux-2.6/mm/page_alloc.c
> ===================================================================
> --- linux-2.6.orig/mm/page_alloc.c
> +++ linux-2.6/mm/page_alloc.c
> @@ -1552,6 +1552,12 @@ restart:
>  rebalance:
>  	if (alloc_flags & ALLOC_NO_WATERMARKS) {
>  nofail_alloc:
> +		/*
> +		 * break out of mempolicy boundaries
> +		 */
> +		zonelist = NODE_DATA(numa_node_id())->node_zonelists +
> +			gfp_zone(gfp_mask);
> +
>  		/* go through the zonelist yet again, ignoring mins */
>  		page = get_page_from_freelist(gfp_mask, order, zonelist,
>  				ALLOC_NO_WATERMARKS);

As is the patch.  People who care about mempolicies will want a better
explanation, please, so they can check that we're not busting their stuff.