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memcg: get rid of memcg_create_cache_name

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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>
This commit is contained in:
Vladimir Davydov 2014-06-04 16:08:23 -07:00 • committed by Linus Torvalds
commit 073ee1c6cd
4 changed files with 16 additions and 29 deletions
Download patch file Download diff file Expand all files Collapse all files

2
include/linux/memcontrol.h
View file

@ -492,8 +492,6 @@ void __memcg_kmem_uncharge_pages(struct page *page, int order);
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);

3
include/linux/slab.h
View file

@ -117,7 +117,8 @@ struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
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 *);

33
mm/memcontrol.c
View file

@ -3095,29 +3095,6 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
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 @@ void memcg_free_cache_params(struct kmem_cache *s)
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 @@ static void memcg_kmem_create_cache(struct mem_cgroup *memcg,
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

7
mm/slab_common.c
View file

@ -264,13 +264,15 @@ EXPORT_SYMBOL(kmem_cache_create);
* 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 @@ struct kmem_cache *kmem_cache_create_memcg(struct mem_cgroup *memcg,
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;