Commit 073ee1c6 authored by Vladimir Davydov's avatar Vladimir Davydov Committed by Linus Torvalds
Browse files

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: default avatarVladimir Davydov <vdavydov@parallels.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b5ffc856

include/linux/memcontrol.h

+0 −2
Original line number Diff line number Diff line
@@ -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);

include/linux/slab.h

+2 −1
Original line number Diff line number Diff line
@@ -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 *);

mm/memcontrol.c

+9 −24
Original line number Diff line number Diff line
@@ -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

mm/slab_common.c

+5 −2
Original line number Diff line number Diff line
@@ -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;

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