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@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Glauber Costa <glommer@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Balbir Singh <bsingharora@xxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 39 ++++++++-------------------------------
1 file changed, 8 insertions(+), 31 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 56fc410..ce25f77 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3391,27 +3391,16 @@ 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.
@@ -3434,25 +3423,13 @@ 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;
--
1.7.10.4
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