From 1d4746d395975e0ff5103e20ab169d1a95b4ef9e Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Fri, 20 May 2016 16:56:44 -0700 Subject: mm, compaction: distinguish COMPACT_DEFERRED from COMPACT_SKIPPED try_to_compact_pages() can currently return COMPACT_SKIPPED even when the compaction is defered for some zone just because zone DMA is skipped in 99% of cases due to watermark checks. This makes COMPACT_DEFERRED basically unusable for the page allocator as a feedback mechanism. Make sure we distinguish those two states properly and switch their ordering in the enum. This would mean that the COMPACT_SKIPPED will be returned only when all eligible zones are skipped. As a result COMPACT_DEFERRED handling for THP in __alloc_pages_slowpath will be more precise and we would bail out rather than reclaim. Signed-off-by: Michal Hocko Acked-by: Vlastimil Babka Acked-by: Hillf Danton Cc: David Rientjes Cc: Johannes Weiner Cc: Joonsoo Kim Cc: Mel Gorman Cc: Tetsuo Handa Cc: Vladimir Davydov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/compaction.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'include/linux/compaction.h') diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 706cbf00e919..11f228712ed5 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -4,13 +4,16 @@ /* Return values for compact_zone() and try_to_compact_pages() */ /* When adding new states, please adjust include/trace/events/compaction.h */ enum compact_result { - /* compaction didn't start as it was deferred due to past failures */ - COMPACT_DEFERRED, /* * compaction didn't start as it was not possible or direct reclaim * was more suitable */ COMPACT_SKIPPED, + /* compaction didn't start as it was deferred due to past failures */ + COMPACT_DEFERRED, + /* compaction not active last round */ + COMPACT_INACTIVE = COMPACT_DEFERRED, + /* compaction should continue to another pageblock */ COMPACT_CONTINUE, /* -- cgit v1.2.3