linux-kernel - [PATCH -mm] memcg: zap memcg_name argument of memcg_create_kmem

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Date:	Tue, 9 Dec 2014 20:11:44 +0300
From:	Vladimir Davydov <vdavydov@...allels.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	Johannes Weiner <hannes@...xchg.org>,
	Michal Hocko <mhocko@...e.cz>, <linux-mm@...ck.org>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH -mm] memcg: zap memcg_name argument of memcg_create_kmem_cache

Instead of passing the name of the memory cgroup which the cache is
created for in the memcg_name_argument, let's obtain it immediately in
memcg_create_kmem_cache.

Signed-off-by: Vladimir Davydov <vdavydov@...allels.com>
---
 include/linux/slab.h |    3 +--
 mm/memcontrol.c      |    5 +----
 mm/slab_common.c     |    9 +++++----
 3 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 9a139b637069..eca9ed303a1b 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -117,8 +117,7 @@ struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
 			void (*)(void *));
 #ifdef CONFIG_MEMCG_KMEM
 struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *,
-					   struct kmem_cache *,
-					   const char *);
+					   struct kmem_cache *);
 #endif
 void kmem_cache_destroy(struct kmem_cache *);
 int kmem_cache_shrink(struct kmem_cache *);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e9086513a42f..e4263e10456c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2606,8 +2606,6 @@ void memcg_update_array_size(int num)
 static void memcg_register_cache(struct mem_cgroup *memcg,
 				 struct kmem_cache *root_cache)
 {
-	static char memcg_name_buf[NAME_MAX + 1]; /* protected by
-						     memcg_slab_mutex */
 	struct kmem_cache *cachep;
 	int id;
 
@@ -2623,8 +2621,7 @@ static void memcg_register_cache(struct mem_cgroup *memcg,
 	if (cache_from_memcg_idx(root_cache, id))
 		return;
 
-	cgroup_name(memcg->css.cgroup, memcg_name_buf, NAME_MAX + 1);
-	cachep = memcg_create_kmem_cache(memcg, root_cache, memcg_name_buf);
+	cachep = memcg_create_kmem_cache(memcg, root_cache);
 	/*
 	 * If we could not create a memcg cache, do not complain, because
 	 * that's not critical at all as we can always proceed with the root
diff --git a/mm/slab_common.c b/mm/slab_common.c
index e03dd6f2a272..b958f27d1833 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -430,16 +430,15 @@ EXPORT_SYMBOL(kmem_cache_create);
  * memcg_create_kmem_cache - Create a cache for a memory cgroup.
  * @memcg: The memory cgroup the new cache is for.
  * @root_cache: The parent of the new cache.
- * @memcg_name: The name of the memory cgroup (used for naming the new cache).
  *
  * This function attempts to create a kmem cache that will serve allocation
  * requests going from @memcg to @root_cache. The new cache inherits properties
  * from its parent.
  */
 struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
-					   struct kmem_cache *root_cache,
-					   const char *memcg_name)
+					   struct kmem_cache *root_cache)
 {
+	static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */
 	struct kmem_cache *s = NULL;
 	char *cache_name;
 
@@ -448,8 +447,10 @@ struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
 
 	mutex_lock(&slab_mutex);
 
+	cgroup_name(mem_cgroup_css(memcg)->cgroup,
+		    memcg_name_buf, sizeof(memcg_name_buf));
 	cache_name = kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name,
-			       memcg_cache_id(memcg), memcg_name);
+			       memcg_cache_id(memcg), memcg_name_buf);
 	if (!cache_name)
 		goto out_unlock;
 
-- 
1.7.10.4

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