Messages in this thread | | | Date | Mon, 20 Oct 2014 11:18:38 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH 3/5] mm, compaction: defer only on COMPACT_COMPLETE |
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On 10/07/2014 11:33 AM, Vlastimil Babka wrote: > Deferred compaction is employed to avoid compacting zone where sync direct > compaction has recently failed. As such, it makes sense to only defer when > a full zone was scanned, which is when compact_zone returns with > COMPACT_COMPLETE. It's less useful to defer when compact_zone returns with > apparent success (COMPACT_PARTIAL), followed by a watermark check failure, > which can happen due to parallel allocation activity. It also does not make > much sense to defer compaction which was completely skipped (COMPACT_SKIP) for > being unsuitable in the first place. > > This patch therefore makes deferred compaction trigger only when > COMPACT_COMPLETE is returned from compact_zone(). Results of stress-highalloc > becnmark show the difference is within measurement error, so the issue is > rather cosmetic. > > Signed-off-by: Vlastimil Babka <vbabka@suse.cz> > Cc: Minchan Kim <minchan@kernel.org> > Cc: Mel Gorman <mgorman@suse.de> > Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> > Cc: Michal Nazarewicz <mina86@mina86.com> > Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> > Cc: Christoph Lameter <cl@linux.com> > Cc: Rik van Riel <riel@redhat.com> > Cc: David Rientjes <rientjes@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
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