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authorVlastimil Babka <vbabka@suse.cz>2016-10-08 02:57:47 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-08 04:46:27 +0300
commita8e025e55b35f7eaf6c6c011de1f98d47ddf0843 (patch)
treea57c771d8f826f64e6d92547e019166cdcf83853 /mm/compaction.c
parent7ceb009a22517297ae0e32863eb86ec766782263 (diff)
downloadlinux-a8e025e55b35f7eaf6c6c011de1f98d47ddf0843.tar.xz
mm, compaction: add the ultimate direct compaction priority
During reclaim/compaction loop, it's desirable to get a final answer from unsuccessful compaction so we can either fail the allocation or invoke the OOM killer. However, heuristics such as deferred compaction or pageblock skip bits can cause compaction to skip parts or whole zones and lead to premature OOM's, failures or excessive reclaim/compaction retries. To remedy this, we introduce a new direct compaction priority called COMPACT_PRIO_SYNC_FULL, which instructs direct compaction to: - ignore deferred compaction status for a zone - ignore pageblock skip hints - ignore cached scanner positions and scan the whole zone The new priority should get eventually picked up by should_compact_retry() and this should improve success rates for costly allocations using __GFP_REPEAT, such as hugetlbfs allocations, and reduce some corner-case OOM's for non-costly allocations. Link: http://lkml.kernel.org/r/20160810091226.6709-6-vbabka@suse.cz [vbabka@suse.cz: use the MIN_COMPACT_PRIORITY alias] Link: http://lkml.kernel.org/r/d443b884-87e7-1c93-8684-3a3a35759fb1@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.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.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index 2e1113ff7a03..21040304f4d2 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1644,6 +1644,8 @@ static enum compact_result compact_zone_order(struct zone *zone, int order,
.alloc_flags = alloc_flags,
.classzone_idx = classzone_idx,
.direct_compaction = true,
+ .whole_zone = (prio == MIN_COMPACT_PRIORITY),
+ .ignore_skip_hint = (prio == MIN_COMPACT_PRIORITY)
};
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
@@ -1689,7 +1691,8 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
ac->nodemask) {
enum compact_result status;
- if (compaction_deferred(zone, order)) {
+ if (prio > MIN_COMPACT_PRIORITY
+ && compaction_deferred(zone, order)) {
rc = max_t(enum compact_result, COMPACT_DEFERRED, rc);
continue;
}