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| author | Vlastimil Babka <vbabka@suse.cz> | 2014-12-10 15:43:28 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-10 17:41:06 -0800 |
| commit | f86697953976b465a55e175ac999d43495a1dacc (patch) | |
| tree | 93028cbcd7fe01b9f607e7016d9fc6bfd96760a3 /mm/compaction.c | |
| parent | 97d47a65be1e513edd02325ae828c9997878b578 (diff) | |
| download | linux-f86697953976b465a55e175ac999d43495a1dacc.tar.gz linux-f86697953976b465a55e175ac999d43495a1dacc.tar.bz2 linux-f86697953976b465a55e175ac999d43495a1dacc.zip | |
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>
Diffstat (limited to 'mm/compaction.c')
| -rw-r--r-- | mm/compaction.c | 2 |
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 |