| Date | Tue, 06 May 2014 13:25:13 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH 07/17] mm: page_alloc: Take the ALLOC_NO_WATERMARK check out of the fast path |
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On 05/01/2014 04:44 AM, Mel Gorman wrote: > ALLOC_NO_WATERMARK is set in a few cases. Always by kswapd, always for > __GFP_MEMALLOC, sometimes for swap-over-nfs, tasks etc. Each of these cases > are relatively rare events but the ALLOC_NO_WATERMARK check is an unlikely > branch in the fast path. This patch moves the check out of the fast path > and after it has been determined that the watermarks have not been met. This > helps the common fast path at the cost of making the slow path slower and > hitting kswapd with a performance cost. It's a reasonable tradeoff. > > Signed-off-by: Mel Gorman <mgorman@suse.de> > Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
-- All rights reversed
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