On Mon, Apr 25, 2016 at 03:35:48PM +0200, Vlastimil Babka wrote:
> From: Hugh Dickins <hu...@google.com>
>
> /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.
>
> [vba...@suse.cz: expanded the changelog]
> Fixes: edc2ca612496 ("mm, compaction: move pageblock checks up from
> isolate_migratepages_range()")
> Cc: sta...@vger.kernel.org
> Cc: Joonsoo Kim <iamjoonsoo....@lge.com>
> Signed-off-by: Hugh Dickins <hu...@google.com>
> Signed-off-by: Vlastimil Babka <vba...@suse.cz>
Acked-by: Joonsoo Kim <iamjoonsoo....@lge.com>
Thanks.
