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authorVladimir Davydov <vdavydov@parallels.com>2014-01-24 00:52:58 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-24 01:36:51 +0100
commit1aa13254259bdef0bca723849ab3bab308d2f0c3 (patch)
tree4d2207788bf99f908ffed696f9d58c96eaf0b8b0 /mm/memcontrol.c
parentmemcg, slab: kmem_cache_create_memcg(): fix memleak on fail path (diff)
downloadlinux-1aa13254259bdef0bca723849ab3bab308d2f0c3.tar.xz
linux-1aa13254259bdef0bca723849ab3bab308d2f0c3.zip
memcg, slab: clean up memcg cache initialization/destruction
Currently, we have rather a messy function set relating to per-memcg kmem cache initialization/destruction. Per-memcg caches are created in memcg_create_kmem_cache(). This function calls kmem_cache_create_memcg() to allocate and initialize a kmem cache and then "registers" the new cache in the memcg_params::memcg_caches array of the parent cache. During its work-flow, kmem_cache_create_memcg() executes the following memcg-related functions: - memcg_alloc_cache_params(), to initialize memcg_params of the newly created cache; - memcg_cache_list_add(), to add the new cache to the memcg_slab_caches list. On the other hand, kmem_cache_destroy() called on a cache destruction only calls memcg_release_cache(), which does all the work: it cleans the reference to the cache in its parent's memcg_params::memcg_caches, removes the cache from the memcg_slab_caches list, and frees memcg_params. Such an inconsistency between destruction and initialization paths make the code difficult to read, so let's clean this up a bit. This patch moves all the code relating to registration of per-memcg caches (adding to memcg list, setting the pointer to a cache from its parent) to the newly created memcg_register_cache() and memcg_unregister_cache() functions making the initialization and destruction paths look symmetrical. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c64
1 files changed, 30 insertions, 34 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b8ebe71f872d..739383cd3f70 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3095,16 +3095,6 @@ static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size)
css_put(&memcg->css);
}
-void memcg_cache_list_add(struct mem_cgroup *memcg, struct kmem_cache *cachep)
-{
- if (!memcg)
- return;
-
- mutex_lock(&memcg->slab_caches_mutex);
- list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches);
- mutex_unlock(&memcg->slab_caches_mutex);
-}
-
/*
* helper for acessing a memcg's index. It will be used as an index in the
* child cache array in kmem_cache, and also to derive its name. This function
@@ -3265,21 +3255,41 @@ void memcg_free_cache_params(struct kmem_cache *s)
kfree(s->memcg_params);
}
-void memcg_release_cache(struct kmem_cache *s)
+void memcg_register_cache(struct kmem_cache *s)
{
struct kmem_cache *root;
struct mem_cgroup *memcg;
int id;
+ if (is_root_cache(s))
+ return;
+
+ root = s->memcg_params->root_cache;
+ memcg = s->memcg_params->memcg;
+ id = memcg_cache_id(memcg);
+
+ css_get(&memcg->css);
+
+ mutex_lock(&memcg->slab_caches_mutex);
+ list_add(&s->memcg_params->list, &memcg->memcg_slab_caches);
+ mutex_unlock(&memcg->slab_caches_mutex);
+
+ root->memcg_params->memcg_caches[id] = s;
/*
- * This happens, for instance, when a root cache goes away before we
- * add any memcg.
+ * the readers won't lock, make sure everybody sees the updated value,
+ * so they won't put stuff in the queue again for no reason
*/
- if (!s->memcg_params)
- return;
+ wmb();
+}
- if (s->memcg_params->is_root_cache)
- goto out;
+void memcg_unregister_cache(struct kmem_cache *s)
+{
+ struct kmem_cache *root;
+ struct mem_cgroup *memcg;
+ int id;
+
+ if (is_root_cache(s))
+ return;
memcg = s->memcg_params->memcg;
id = memcg_cache_id(memcg);
@@ -3292,8 +3302,6 @@ void memcg_release_cache(struct kmem_cache *s)
mutex_unlock(&memcg->slab_caches_mutex);
css_put(&memcg->css);
-out:
- memcg_free_cache_params(s);
}
/*
@@ -3451,26 +3459,13 @@ static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
mutex_lock(&memcg_cache_mutex);
new_cachep = cache_from_memcg_idx(cachep, idx);
- if (new_cachep) {
- css_put(&memcg->css);
+ if (new_cachep)
goto out;
- }
new_cachep = kmem_cache_dup(memcg, cachep);
- if (new_cachep == NULL) {
+ if (new_cachep == NULL)
new_cachep = cachep;
- css_put(&memcg->css);
- goto out;
- }
-
- atomic_set(&new_cachep->memcg_params->nr_pages , 0);
- cachep->memcg_params->memcg_caches[idx] = new_cachep;
- /*
- * the readers won't lock, make sure everybody sees the updated value,
- * so they won't put stuff in the queue again for no reason
- */
- wmb();
out:
mutex_unlock(&memcg_cache_mutex);
return new_cachep;
@@ -3550,6 +3545,7 @@ static void memcg_create_cache_work_func(struct work_struct *w)
cw = container_of(w, struct create_work, work);
memcg_create_kmem_cache(cw->memcg, cw->cachep);
+ css_put(&cw->memcg->css);
kfree(cw);
}