Currently, we use memcg_cache_id as a part of a per memcg cache name. Since memcg_cache_id is released only on css free, this guarantees cache name uniqueness.
However, it's a bad practice to keep memcg_cache_id till css free, because it occupies a slot in kmem_cache->memcg_params->memcg_caches arrays. So I'm going to make memcg release memcg_cache_id on css offline. As a result, memcg_cache_id won't guarantee cache name uniqueness any more. Signed-off-by: Vladimir Davydov <[email protected]> --- include/linux/slab.h | 2 +- mm/memcontrol.c | 13 +++++++++++-- mm/slab_common.c | 15 +++------------ 3 files changed, 15 insertions(+), 15 deletions(-) diff --git a/include/linux/slab.h b/include/linux/slab.h index c265bec6a57d..f4d489aee6cb 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -118,7 +118,7 @@ struct kmem_cache *kmem_cache_create(const char *, size_t, size_t, #ifdef CONFIG_MEMCG_KMEM struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *, struct kmem_cache *, - const char *); + 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 7361bd8b720a..16fcdbef1b7d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2995,6 +2995,7 @@ static void memcg_register_cache(struct mem_cgroup *memcg, static char memcg_name_buf[NAME_MAX + 1]; /* protected by memcg_slab_mutex */ struct kmem_cache *cachep; + char *cache_name; int id; lockdep_assert_held(&memcg_slab_mutex); @@ -3010,14 +3011,22 @@ static void memcg_register_cache(struct mem_cgroup *memcg, return; cgroup_name(memcg->css.cgroup, memcg_name_buf, NAME_MAX + 1); - cachep = memcg_create_kmem_cache(memcg, root_cache, memcg_name_buf); + + cache_name = kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name, + mem_cgroup_id(memcg), memcg_name_buf); + if (!cache_name) + return; + + cachep = memcg_create_kmem_cache(memcg, root_cache, cache_name); /* * 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 * cache. */ - if (!cachep) + if (!cachep) { + kfree(cache_name); return; + } css_get(&memcg->css); list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches); diff --git a/mm/slab_common.c b/mm/slab_common.c index 800314e2a075..8b486f05c414 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -345,7 +345,7 @@ 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). + * @cache_name: The string to be used as the new cache name. * * This function attempts to create a kmem cache that will serve allocation * requests going from @memcg to @root_cache. The new cache inherits properties @@ -353,31 +353,22 @@ EXPORT_SYMBOL(kmem_cache_create); */ struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, struct kmem_cache *root_cache, - const char *memcg_name) + char *cache_name) { struct kmem_cache *s = NULL; - char *cache_name; get_online_cpus(); get_online_mems(); mutex_lock(&slab_mutex); - cache_name = kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name, - memcg_cache_id(memcg), memcg_name); - if (!cache_name) - goto out_unlock; - s = do_kmem_cache_create(cache_name, root_cache->object_size, root_cache->size, root_cache->align, root_cache->flags, root_cache->ctor, memcg, root_cache); - if (IS_ERR(s)) { - kfree(cache_name); + if (IS_ERR(s)) s = NULL; - } -out_unlock: mutex_unlock(&slab_mutex); put_online_mems(); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
