The patch titled
Subject: mm, compaction: don't isolate PageWriteback pages in MIGRATE_SYNC_LIGHT mode
has been added to the -mm tree. Its filename is
mm-compaction-dont-isolate-pagewriteback-pages-in-migrate_sync_light-mode.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-compaction-dont-isolate-pagewriteback-pages-in-migrate_sync_light-mode.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-compaction-dont-isolate-pagewriteback-pages-in-migrate_sync_light-mode.patch
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: mm, compaction: don't isolate PageWriteback pages in MIGRATE_SYNC_LIGHT mode
At present MIGRATE_SYNC_LIGHT is allowing __isolate_lru_page() to isolate
a PageWriteback page, which __unmap_and_move() then rejects with -EBUSY:
of course the writeback might complete in between, but that's not what we
usually expect, so probably better not to isolate it.
When tested by stress-highalloc from mmtests, this has reduced the number
of page migrate failures by 60-70%.
Link: http://lkml.kernel.org/r/20160721073614.24395-2-vbabka@xxxxxxx
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Acked-by: 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-dont-isolate-pagewriteback-pages-in-migrate_sync_light-mode mm/compaction.c
--- a/mm/compaction.c~mm-compaction-dont-isolate-pagewriteback-pages-in-migrate_sync_light-mode
+++ a/mm/compaction.c
@@ -1200,7 +1200,7 @@ static isolate_migrate_t isolate_migrate
struct page *page;
const isolate_mode_t isolate_mode =
(sysctl_compact_unevictable_allowed ? ISOLATE_UNEVICTABLE : 0) |
- (cc->mode == MIGRATE_ASYNC ? ISOLATE_ASYNC_MIGRATE : 0);
+ (cc->mode != MIGRATE_SYNC ? ISOLATE_ASYNC_MIGRATE : 0);
/*
* Start at where we last stopped, or beginning of the zone as
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
shmem-get_unmapped_area-align-huge-page.patch
mm-compaction-dont-isolate-pagewriteback-pages-in-migrate_sync_light-mode.patch
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