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| author | Hugh Dickins <hughd@google.com> | 2016-05-05 16:22:15 -0700 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2016-05-17 13:43:02 -0400 |
| commit | c58ca6100b3d1b9890776d9fdd8aa12352d49bc8 (patch) | |
| tree | 7f87b7c8052a6ba1de4395066d24c10291305b29 /mm | |
| parent | c42d74f018b072b30570856dd43ff582c4e5117e (diff) | |
| download | lwn-c58ca6100b3d1b9890776d9fdd8aa12352d49bc8.tar.gz lwn-c58ca6100b3d1b9890776d9fdd8aa12352d49bc8.zip | |
mm, cma: prevent nr_isolated_* counters from going negative
[ Upstream commit 14af4a5e9b26ad251f81c174e8a43f3e179434a5 ]
/proc/sys/vm/stat_refresh warns nr_isolated_anon and nr_isolated_file go
increasingly negative under compaction: which would add delay when
should be none, or no delay when should delay. The bug in compaction
was due to a recent mmotm patch, but much older instance of the bug was
also noticed in isolate_migratepages_range() which is used for CMA and
gigantic hugepage allocations.
The bug is caused by putback_movable_pages() in an error path
decrementing the isolated counters without them being previously
incremented by acct_isolated(). Fix isolate_migratepages_range() by
removing the error-path putback, thus reaching acct_isolated() with
migratepages still isolated, and leaving putback to caller like most
other places do.
Fixes: edc2ca612496 ("mm, compaction: move pageblock checks up from isolate_migratepages_range()")
[vbabka@suse.cz: expanded the changelog]
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/compaction.c | 10 |
1 files changed, 1 insertions, 9 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 018f08da99a2..3dcf93cd622b 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -853,16 +853,8 @@ isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn, pfn = isolate_migratepages_block(cc, pfn, block_end_pfn, ISOLATE_UNEVICTABLE); - /* - * In case of fatal failure, release everything that might - * have been isolated in the previous iteration, and signal - * the failure back to caller. - */ - if (!pfn) { - putback_movable_pages(&cc->migratepages); - cc->nr_migratepages = 0; + if (!pfn) break; - } if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) break; |