From: Vladimir Davydov <vdavy...@parallels.com>

commit ec97097bca147d5718a5d2c024d1ec740b10096d upstream.

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 <vdavy...@parallels.com>
Reported-by: Dave Chinner <dchin...@redhat.com>
Cc: Mel Gorman <mgor...@suse.de>
Cc: Michal Hocko <mho...@suse.cz>
Cc: Johannes Weiner <han...@cmpxchg.org>
Cc: Rik van Riel <r...@redhat.com>
Cc: Glauber Costa <glom...@gmail.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Mel Gorman <mgor...@suse.de>
---
 mm/vmscan.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 0506995..e36294b 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);
 
                }
        }
-- 
1.8.4.5

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