From 842e2873697e023d140a8905a41fcf39d4e546f1 Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Thu, 23 Jan 2014 15:53:03 -0800 Subject: [PATCH] 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 Cc: Michal Hocko Cc: Glauber Costa Cc: Johannes Weiner Cc: Balbir Singh Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 39 ++++++++------------------------------- 1 file 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; -- 2.20.1