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authorVladimir Davydov <vdavydov@parallels.com>2014-01-24 00:53:03 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-24 01:36:51 +0100
commit842e2873697e023d140a8905a41fcf39d4e546f1 (patch)
tree5ba705288c9cc5cee0e22a3c55166e8982c994db /mm/memcontrol.c
parentmemcg, slab: fix races in per-memcg cache creation/destruction (diff)
downloadlinux-842e2873697e023d140a8905a41fcf39d4e546f1.tar.xz
linux-842e2873697e023d140a8905a41fcf39d4e546f1.zip
memcg: get rid of kmem_cache_dup()
kmem_cache_dup() is only called from memcg_create_kmem_cache(). The latter, in fact, does nothing besides this, so let's fold kmem_cache_dup() into memcg_create_kmem_cache(). This patch also makes the memcg_cache_mutex private to memcg_create_kmem_cache(), because it is not used anywhere else. 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> 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.c39
1 files changed, 8 insertions, 31 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d2da65c4cd84..80197e544764 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3427,27 +3427,16 @@ void mem_cgroup_destroy_cache(struct kmem_cache *cachep)
schedule_work(&cachep->memcg_params->destroy);
}
-/*
- * This lock protects updaters, not readers. We want readers to be as fast as
- * they can, and they will either see NULL or a valid cache value. Our model
- * allow them to see NULL, in which case the root memcg will be selected.
- *
- * We need this lock because multiple allocations to the same cache from a non
- * will span more than one worker. Only one of them can create the cache.
- */
-static DEFINE_MUTEX(memcg_cache_mutex);
-
-/*
- * Called with memcg_cache_mutex held
- */
-static struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
- struct kmem_cache *s)
+static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
+ struct kmem_cache *s)
{
struct kmem_cache *new;
static char *tmp_name = NULL;
+ static DEFINE_MUTEX(mutex); /* protects tmp_name */
- lockdep_assert_held(&memcg_cache_mutex);
+ BUG_ON(!memcg_can_account_kmem(memcg));
+ mutex_lock(&mutex);
/*
* kmem_cache_create_memcg duplicates the given name and
* cgroup_name for this name requires RCU context.
@@ -3470,25 +3459,13 @@ static struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
if (new)
new->allocflags |= __GFP_KMEMCG;
+ else
+ new = s;
+ mutex_unlock(&mutex);
return new;
}
-static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
- struct kmem_cache *cachep)
-{
- struct kmem_cache *new_cachep;
-
- BUG_ON(!memcg_can_account_kmem(memcg));
-
- mutex_lock(&memcg_cache_mutex);
- new_cachep = kmem_cache_dup(memcg, cachep);
- if (new_cachep == NULL)
- new_cachep = cachep;
- mutex_unlock(&memcg_cache_mutex);
- return new_cachep;
-}
-
void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
{
struct kmem_cache *c;