Re: [PATCH 5/6] mm: page_alloc: Abort fair zone allocation policy when remotes nodes are encountered

From: Johannes Weiner
Date: Thu Jul 10 2014 - 08:14:31 EST

On Wed, Jul 09, 2014 at 09:13:07AM +0100, Mel Gorman wrote:
> The purpose of numa_zonelist_order=zone is to preserve lower zones
> for use with 32-bit devices. If locality is preferred then the
> numa_zonelist_order=node policy should be used. Unfortunately, the fair
> zone allocation policy overrides this by skipping zones on remote nodes
> until the lower one is found. While this makes sense from a page aging
> and performance perspective, it breaks the expected zonelist policy. This
> patch restores the expected behaviour for zone-list ordering.
> Signed-off-by: Mel Gorman <mgorman@xxxxxxx>

32-bit NUMA? :-) Anyway, this change also cuts down the fair pass
overhead on bigger NUMA machines, so I'm all for it.

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
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