1 files changed, 14 insertions, 7 deletions

diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
index 6794490f25b2..9443cafd1969 100644
--- a/include/linux/shrinker.h
+++ b/include/linux/shrinker.h
@@ -12,6 +12,9 @@
 struct shrink_control {
         gfp_t gfp_mask;
 
+        /* current node being shrunk (for NUMA aware shrinkers) */
+        int nid;
+
         /*
          * How many objects scan_objects should scan and try to reclaim.
          * This is reset before every call, so it is safe for callees
@@ -26,20 +29,20 @@ struct shrink_control {
          */
         unsigned long nr_scanned;
 
-        /* current node being shrunk (for NUMA aware shrinkers) */
-        int nid;
-
         /* current memcg being shrunk (for memcg aware shrinkers) */
         struct mem_cgroup *memcg;
 };
 
 #define SHRINK_STOP (~0UL)
+#define SHRINK_EMPTY (~0UL - 1)
 /*
  * A callback you can register to apply pressure to ageable caches.
  *
  * @count_objects should return the number of freeable items in the cache. If
- * there are no objects to free or the number of freeable items cannot be
- * determined, it should return 0. No deadlock checks should be done during the
+ * there are no objects to free, it should return SHRINK_EMPTY, while 0 is
+ * returned in cases of the number of freeable items cannot be determined
+ * or shrinker should skip this cache for this time (e.g., their number
+ * is below shrinkable limit). No deadlock checks should be done during the
  * count callback - the shrinker relies on aggregating scan counts that couldn't
  * be executed due to potential deadlocks to be run at a later call when the
  * deadlock condition is no longer pending.
@@ -60,12 +63,16 @@ struct shrinker {
         unsigned long (*scan_objects)(struct shrinker *,
                                       struct shrink_control *sc);
 
-        int seeks;      /* seeks to recreate an obj */
         long batch;     /* reclaim batch size, 0 = default */
-        unsigned long flags;
+        int seeks;      /* seeks to recreate an obj */
+        unsigned flags;
 
         /* These are for internal use */
         struct list_head list;
+#ifdef CONFIG_MEMCG_KMEM
+        /* ID in shrinker_idr */
+        int id;
+#endif
         /* objs pending delete, per node */
         atomic_long_t *nr_deferred;
 };