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authorMel Gorman <mgorman@techsingularity.net>2019-03-05 15:44:50 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-05 21:07:16 -0800
commitfd1444b2729289ea3ef6b6096be604f8983e9f9f (patch)
tree871ef064d6a99b7b9bb664a6e1705ab082d75c57 /mm
parentefe771c7603bc524425070d651e70e9c56c57f28 (diff)
mm, compaction: ignore the fragmentation avoidance boost for isolation and compaction
When pageblocks get fragmented, watermarks are artifically boosted to reclaim pages to avoid further fragmentation events. However, compaction is often either fragmentation-neutral or moving movable pages away from unmovable/reclaimable pages. As the true watermarks are preserved, allow compaction to ignore the boost factor. The expected impact is very slight as the main benefit is that compaction is slightly more likely to succeed when the system has been fragmented very recently. On both 1-socket and 2-socket machines for THP-intensive allocation during fragmentation the success rate was increased by less than 1% which is marginal. However, detailed tracing indicated that failure of migration due to a premature ENOMEM triggered by watermark checks were eliminated. Link: http://lkml.kernel.org/r/20190118175136.31341-9-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: YueHaibing <yuehaibing@huawei.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/page_alloc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8afb6f007f68..2e132b9e7a93 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2962,7 +2962,7 @@ int __isolate_free_page(struct page *page, unsigned int order)
* watermark, because we already know our high-order page
* exists.
*/
- watermark = min_wmark_pages(zone) + (1UL << order);
+ watermark = zone->_watermark[WMARK_MIN] + (1UL << order);
if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
return 0;