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>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 45c1cf61cbed8c8747df1d5dd845a4f98daff6c5..90c4075d8d75af6358ba6c789bc0747f53460a4d 100644 (file)
--- 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);
 
                }
        }