vmscan: per memory cgroup slab shrinkers

This patch adds SHRINKER_MEMCG_AWARE flag.  If a shrinker has this flag
set, it will be called per memory cgroup.  The memory cgroup to scan
objects from is passed in shrink_control->memcg.  If the memory cgroup
is NULL, a memcg aware shrinker is supposed to scan objects from the
global list.  Unaware shrinkers are only called on global pressure with
memcg=NULL.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Greg Thelen <gthelen@google.com>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 14 deletions

diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 2bc2c87f35e7..5718cb9f7273 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -37,20 +37,6 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
         iput(toput_inode);
 }
 
-static void drop_slab(void)
-{
-        int nr_objects;
-
-        do {
-                int nid;
-
-                nr_objects = 0;
-                for_each_online_node(nid)
-                        nr_objects += shrink_node_slabs(GFP_KERNEL, nid,
-                                                        1000, 1000);
-        } while (nr_objects > 10);
-}
-
 int drop_caches_sysctl_handler(struct ctl_table *table, int write,
         void __user *buffer, size_t *length, loff_t *ppos)
 {