mm: vmscan: fix memcg-aware shrinkers not called on global reclaim

We must call shrink_slab() for each memory cgroup on both global and
memcg reclaim in shrink_node_memcg().  Commit d71df22b55099 accidentally
changed that so that now shrink_slab() is only called with memcg != NULL
on memcg reclaim.  As a result, memcg-aware shrinkers (including
dentry/inode) are never invoked on global reclaim.  Fix that.

Fixes: b2e18757f2c9 ("mm, vmscan: begin reclaiming pages on a per-node basis")
Link: http://lkml.kernel.org/r/1470056590-7177-1-git-send-email-vdavydov@virtuozzo.com
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 650d26832569a9c41399f3a5da49c6eb56015d46..374d95d0417856b096d902d40ff7cc29d4021b2e 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2561,7 +2561,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
                        shrink_node_memcg(pgdat, memcg, sc, &lru_pages);
                        node_lru_pages += lru_pages;
 
-                       if (!global_reclaim(sc))
+                       if (memcg)
                                shrink_slab(sc->gfp_mask, pgdat->node_id,
                                            memcg, sc->nr_scanned - scanned,
                                            lru_pages);