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authorVlastimil Babka <vbabka@suse.cz>2014-12-10 15:43:28 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-10 17:41:06 -0800
commitf86697953976b465a55e175ac999d43495a1dacc (patch)
tree93028cbcd7fe01b9f607e7016d9fc6bfd96760a3
parent97d47a65be1e513edd02325ae828c9997878b578 (diff)
mm, compaction: defer only on COMPACT_COMPLETE
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> Acked-by: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/compaction.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index 75f4c1206d00..eaf0a925ff26 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1362,7 +1362,7 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
goto break_loop;
}
- if (mode != MIGRATE_ASYNC) {
+ if (mode != MIGRATE_ASYNC && status == COMPACT_COMPLETE) {
/*
* We think that allocation won't succeed in this zone
* so we defer compaction there. If it ends up