memcg: aggregate memcg cache values in slabinfo

When we create caches in memcgs, we need to display their usage
information somewhere.  We'll adopt a scheme similar to /proc/meminfo,
with aggregate totals shown in the global file, and per-group information
stored in the group itself.

For the time being, only reads are allowed in the per-group cache.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.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>

2 files changed, 12 insertions, 0 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e119f3ef793c..8dc7c746b44f 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -420,6 +420,11 @@ static inline void sock_release_memcg(struct sock *sk)
 
 #ifdef CONFIG_MEMCG_KMEM
 extern struct static_key memcg_kmem_enabled_key;
+
+extern int memcg_limited_groups_array_size;
+#define for_each_memcg_cache_index(_idx)        \
+        for ((_idx) = 0; i < memcg_limited_groups_array_size; (_idx)++)
+
 static inline bool memcg_kmem_enabled(void)
 {
         return static_key_false(&memcg_kmem_enabled_key);
@@ -557,6 +562,9 @@ memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
         return __memcg_kmem_get_cache(cachep, gfp);
 }
 #else
+#define for_each_memcg_cache_index(_idx)        \
+        for (; NULL; )
+
 static inline bool memcg_kmem_enabled(void)
 {
         return false;
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 869efb8d2377..b9278663f22a 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -220,6 +220,10 @@ struct memcg_cache_params {
 
 int memcg_update_all_caches(int num_memcgs);
 
+struct seq_file;
+int cache_show(struct kmem_cache *s, struct seq_file *m);
+void print_slabinfo_header(struct seq_file *m);
+
 /*
  * Common kmalloc functions provided by all allocators
  */