slab: use css id for naming per memcg caches

Currently, we use mem_cgroup->kmemcg_id to guarantee kmem_cache->name
uniqueness.  This is correct, because kmemcg_id is only released on css
free after destroying all per memcg caches.

However, I am going to change that and release kmemcg_id on css offline,
because it is not wise to keep it for so long, wasting valuable entries of
memcg_cache_params->memcg_caches arrays.  Therefore, to preserve cache
name uniqueness, let us switch to css->id.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Chinner <david@fromorbit.com>
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 2015-02-12 14:59:29 -08:00 committed by Linus Torvalds
parent 01e586598b
commit f1008365bb

View File

@ -488,6 +488,7 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg,
struct kmem_cache *root_cache)
{
static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */
struct cgroup_subsys_state *css = mem_cgroup_css(memcg);
struct memcg_cache_array *arr;
struct kmem_cache *s = NULL;
char *cache_name;
@ -510,10 +511,9 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg,
if (arr->entries[idx])
goto out_unlock;
cgroup_name(mem_cgroup_css(memcg)->cgroup,
memcg_name_buf, sizeof(memcg_name_buf));
cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf));
cache_name = kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name,
idx, memcg_name_buf);
css->id, memcg_name_buf);
if (!cache_name)
goto out_unlock;