[v2 PATCH 7/9] mm: vmscan: don't need allocate shrinker->nr_deferred for memcg aware shrinkers

[Yang Shi]

Now nr_deferred is available on per memcg level for memcg aware shrinkers, so 
don't need
allocate shrinker->nr_deferred for such shrinkers anymore.

Signed-off-by: Yang Shi <shy828...@gmail.com>
---
 mm/vmscan.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index bce8cf44eca2..8d5bfd818acd 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -420,7 +420,15 @@ unsigned long lruvec_lru_size(struct lruvec *lruvec, enum 
lru_list lru, int zone
  */
 int prealloc_shrinker(struct shrinker *shrinker)
 {
-       unsigned int size = sizeof(*shrinker->nr_deferred);
+       unsigned int size;
+
+       if (is_deferred_memcg_aware(shrinker)) {
+               if (prealloc_memcg_shrinker(shrinker))
+                       return -ENOMEM;
+               return 0;
+       }
+
+       size = sizeof(*shrinker->nr_deferred);
 
        if (shrinker->flags & SHRINKER_NUMA_AWARE)
                size *= nr_node_ids;
@@ -429,26 +437,18 @@ int prealloc_shrinker(struct shrinker *shrinker)
        if (!shrinker->nr_deferred)
                return -ENOMEM;
 
-       if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
-               if (prealloc_memcg_shrinker(shrinker))
-                       goto free_deferred;
-       }
-
        return 0;
-
-free_deferred:
-       kfree(shrinker->nr_deferred);
-       shrinker->nr_deferred = NULL;
-       return -ENOMEM;
 }
 
 void free_prealloced_shrinker(struct shrinker *shrinker)
 {
-       if (!shrinker->nr_deferred)
+       if (is_deferred_memcg_aware(shrinker)) {
+               unregister_memcg_shrinker(shrinker);
                return;
+       }
 
-       if (shrinker->flags & SHRINKER_MEMCG_AWARE)
-               unregister_memcg_shrinker(shrinker);
+       if (!shrinker->nr_deferred)
+               return;
 
        kfree(shrinker->nr_deferred);
        shrinker->nr_deferred = NULL;
-- 
2.26.2