memcg: get rid of memcg_create_cache_name
Instead of calling back to memcontrol.c from kmem_cache_create_memcg in
order to just create the name of a per memcg cache, let's allocate it in
place. We only need to pass the memcg name to kmem_cache_create_memcg for
that - everything else can be done in slab_common.c.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 1fa2324..dfc2929 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -492,8 +492,6 @@
int memcg_cache_id(struct mem_cgroup *memcg);
-char *memcg_create_cache_name(struct mem_cgroup *memcg,
- struct kmem_cache *root_cache);
int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
struct kmem_cache *root_cache);
void memcg_free_cache_params(struct kmem_cache *s);
diff --git a/include/linux/slab.h b/include/linux/slab.h
index ecbec9c..86e5b26 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -117,7 +117,8 @@
void (*)(void *));
#ifdef CONFIG_MEMCG_KMEM
struct kmem_cache *kmem_cache_create_memcg(struct mem_cgroup *,
- struct kmem_cache *);
+ struct kmem_cache *,
+ const char *);
#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 971d7b6..7df7f59 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3095,29 +3095,6 @@
return 0;
}
-char *memcg_create_cache_name(struct mem_cgroup *memcg,
- struct kmem_cache *root_cache)
-{
- static char *buf;
-
- /*
- * We need a mutex here to protect the shared buffer. Since this is
- * expected to be called only on cache creation, we can employ the
- * slab_mutex for that purpose.
- */
- lockdep_assert_held(&slab_mutex);
-
- if (!buf) {
- buf = kmalloc(NAME_MAX + 1, GFP_KERNEL);
- if (!buf)
- return NULL;
- }
-
- cgroup_name(memcg->css.cgroup, buf, NAME_MAX + 1);
- return kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name,
- memcg_cache_id(memcg), buf);
-}
-
int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
struct kmem_cache *root_cache)
{
@@ -3158,6 +3135,7 @@
static void memcg_kmem_create_cache(struct mem_cgroup *memcg,
struct kmem_cache *root_cache)
{
+ static char *memcg_name_buf; /* protected by memcg_slab_mutex */
struct kmem_cache *cachep;
int id;
@@ -3173,7 +3151,14 @@
if (cache_from_memcg_idx(root_cache, id))
return;
- cachep = kmem_cache_create_memcg(memcg, root_cache);
+ if (!memcg_name_buf) {
+ memcg_name_buf = kmalloc(NAME_MAX + 1, GFP_KERNEL);
+ if (!memcg_name_buf)
+ return;
+ }
+
+ cgroup_name(memcg->css.cgroup, memcg_name_buf, NAME_MAX + 1);
+ cachep = kmem_cache_create_memcg(memcg, root_cache, memcg_name_buf);
/*
* 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 7e348cf..3217561 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -264,13 +264,15 @@
* kmem_cache_create_memcg - 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 *kmem_cache_create_memcg(struct mem_cgroup *memcg,
- struct kmem_cache *root_cache)
+ struct kmem_cache *root_cache,
+ const char *memcg_name)
{
struct kmem_cache *s = NULL;
char *cache_name;
@@ -280,7 +282,8 @@
mutex_lock(&slab_mutex);
- cache_name = memcg_create_cache_name(memcg, root_cache);
+ cache_name = kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name,
+ memcg_cache_id(memcg), memcg_name);
if (!cache_name)
goto out_unlock;