mm: vmscan: call NUMA-unaware shrinkers irrespective of nodemask

If a shrinker is not NUMA-aware, shrink_slab() should call it exactly
once with nid=0, but currently it is not true: if node 0 is not set in
the nodemask or if it is not online, we will not call such shrinkers at
all.  As a result some slabs will be left untouched under some
circumstances.  Let us fix it.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Reported-by: Dave Chinner <dchinner@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Glauber Costa <glommer@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 9 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 45c1cf61cbed..90c4075d8d75 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -369,16 +369,17 @@ unsigned long shrink_slab(struct shrink_control *shrinkctl,
         }
 
         list_for_each_entry(shrinker, &shrinker_list, list) {
-                for_each_node_mask(shrinkctl->nid, shrinkctl->nodes_to_scan) {
-                        if (!node_online(shrinkctl->nid))
-                                continue;
-
-                        if (!(shrinker->flags & SHRINKER_NUMA_AWARE) &&
-                            (shrinkctl->nid != 0))
-                                break;
-
+                if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) {
+                        shrinkctl->nid = 0;
                         freed += shrink_slab_node(shrinkctl, shrinker,
-                                 nr_pages_scanned, lru_pages);
+                                        nr_pages_scanned, lru_pages);
+                        continue;
+                }
+
+                for_each_node_mask(shrinkctl->nid, shrinkctl->nodes_to_scan) {
+                        if (node_online(shrinkctl->nid))
+                                freed += shrink_slab_node(shrinkctl, shrinker,
+                                                nr_pages_scanned, lru_pages);
 
                 }
         }