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| author | Michal Hocko <mhocko@suse.com> | 2016-05-21 02:56:44 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-21 03:58:30 +0300 |
| commit | 1d4746d395975e0ff5103e20ab169d1a95b4ef9e (patch) | |
| tree | a5890a92a5059dde4f5746c544f3defcb2a80c88 /mm | |
| parent | c46649deae3f00aa8ba8716f0ddb8eef2dc9532f (diff) | |
| download | linux-1d4746d395975e0ff5103e20ab169d1a95b4ef9e.tar.xz | |
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 <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/compaction.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 455ecd87f48d..b2b94474dd28 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1578,7 +1578,7 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order, int may_perform_io = gfp_mask & __GFP_IO; struct zoneref *z; struct zone *zone; - enum compact_result rc = COMPACT_DEFERRED; + enum compact_result rc = COMPACT_SKIPPED; int all_zones_contended = COMPACT_CONTENDED_LOCK; /* init for &= op */ *contended = COMPACT_CONTENDED_NONE; @@ -1595,8 +1595,10 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order, enum compact_result status; int zone_contended; - if (compaction_deferred(zone, order)) + if (compaction_deferred(zone, order)) { + rc = max_t(enum compact_result, COMPACT_DEFERRED, rc); continue; + } status = compact_zone_order(zone, order, gfp_mask, mode, &zone_contended, alloc_flags, @@ -1667,7 +1669,7 @@ break_loop: * If at least one zone wasn't deferred or skipped, we report if all * zones that were tried were lock contended. */ - if (rc > COMPACT_SKIPPED && all_zones_contended) + if (rc > COMPACT_INACTIVE && all_zones_contended) *contended = COMPACT_CONTENDED_LOCK; return rc; |