The patch titled
Subject: mm, compaction: defer only on COMPACT_COMPLETE
has been added to the -mm tree. Its filename is
mm-compaction-defer-only-on-compact_complete.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-compaction-defer-only-on-compact_complete.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-compaction-defer-only-on-compact_complete.patch
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From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: 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@xxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Michal Nazarewicz <mina86@xxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/compaction.c~mm-compaction-defer-only-on-compact_complete mm/compaction.c
--- a/mm/compaction.c~mm-compaction-defer-only-on-compact_complete
+++ a/mm/compaction.c
@@ -1343,7 +1343,7 @@ unsigned long try_to_compact_pages(struc
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
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
origin.patch
mm-compaction-avoid-premature-range-skip-in-isolate_migratepages_range.patch
mm-introduce-single-zone-pcplists-drain.patch
mm-page_isolation-drain-single-zone-pcplists.patch
mm-cma-drain-single-zone-pcplists.patch
mm-memory_hotplug-failure-drain-single-zone-pcplists.patch
mm-compaction-pass-classzone_idx-and-alloc_flags-to-watermark-checking.patch
mm-compaction-simplify-deferred-compaction.patch
mm-compaction-defer-only-on-compact_complete.patch
mm-compaction-always-update-cached-scanner-positions.patch
mm-compaction-more-focused-lru-and-pcplists-draining.patch
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