[PATCH -mm] memcg: zap memcg_name argument of memcg_create_kmem_cache

From: Vladimir Davydov
Date: Tue Dec 09 2014 - 12:11:57 EST


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@xxxxxxxxxxxxx>
---
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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