From 5722d094ad2b56fa2c1cb3adaf40071a55bbf242 Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Mon, 7 Apr 2014 15:39:24 -0700 Subject: [PATCH] memcg, slab: cleanup memcg cache creation This patch cleans up the memcg cache creation path as follows: - Move memcg cache name creation to a separate function to be called from kmem_cache_create_memcg(). This allows us to get rid of the mutex protecting the temporary buffer used for the name formatting, because the whole cache creation path is protected by the slab_mutex. - Get rid of memcg_create_kmem_cache(). This function serves as a proxy to kmem_cache_create_memcg(). After separating the cache name creation path, it would be reduced to a function call, so let's inline it. Signed-off-by: Vladimir Davydov Cc: Michal Hocko Cc: Johannes Weiner Cc: David Rientjes Cc: Pekka Enberg Cc: Glauber Costa Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 9 ++++ mm/memcontrol.c | 89 +++++++++++++++++--------------------- mm/slab_common.c | 5 ++- 3 files changed, 52 insertions(+), 51 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 96f3fc87ab96..ab7f02884983 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -491,6 +491,9 @@ void __memcg_kmem_commit_charge(struct page *page, void __memcg_kmem_uncharge_pages(struct page *page, int order); int memcg_cache_id(struct mem_cgroup *memcg); + +char *memcg_create_cache_name(struct mem_cgroup *memcg, + struct kmem_cache *root_cache); int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s, struct kmem_cache *root_cache); void memcg_free_cache_params(struct kmem_cache *s); @@ -635,6 +638,12 @@ static inline int memcg_cache_id(struct mem_cgroup *memcg) return -1; } +static inline char *memcg_create_cache_name(struct mem_cgroup *memcg, + struct kmem_cache *root_cache) +{ + return NULL; +} + static inline int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s, struct kmem_cache *root_cache) { diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e33b1d09eb1f..32c7342df4bf 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3094,6 +3094,29 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups) return 0; } +char *memcg_create_cache_name(struct mem_cgroup *memcg, + struct kmem_cache *root_cache) +{ + static char *buf = NULL; + + /* + * We need a mutex here to protect the shared buffer. Since this is + * expected to be called only on cache creation, we can employ the + * slab_mutex for that purpose. + */ + lockdep_assert_held(&slab_mutex); + + if (!buf) { + buf = kmalloc(NAME_MAX + 1, GFP_KERNEL); + if (!buf) + return NULL; + } + + cgroup_name(memcg->css.cgroup, buf, NAME_MAX + 1); + return kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name, + memcg_cache_id(memcg), buf); +} + int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s, struct kmem_cache *root_cache) { @@ -3298,46 +3321,6 @@ void mem_cgroup_destroy_cache(struct kmem_cache *cachep) schedule_work(&cachep->memcg_params->destroy); } -static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, - struct kmem_cache *s) -{ - struct kmem_cache *new = NULL; - static char *tmp_path = NULL, *tmp_name = NULL; - static DEFINE_MUTEX(mutex); /* protects tmp_name */ - - 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. - * This static temporary buffer is used to prevent from - * pointless shortliving allocation. - */ - if (!tmp_path || !tmp_name) { - if (!tmp_path) - tmp_path = kmalloc(PATH_MAX, GFP_KERNEL); - if (!tmp_name) - tmp_name = kmalloc(NAME_MAX + 1, GFP_KERNEL); - if (!tmp_path || !tmp_name) - goto out; - } - - cgroup_name(memcg->css.cgroup, tmp_name, NAME_MAX + 1); - snprintf(tmp_path, PATH_MAX, "%s(%d:%s)", s->name, - memcg_cache_id(memcg), tmp_name); - - new = kmem_cache_create_memcg(memcg, tmp_path, s->object_size, s->align, - (s->flags & ~SLAB_PANIC), s->ctor, s); - if (new) - new->allocflags |= __GFP_KMEMCG; - else - new = s; -out: - mutex_unlock(&mutex); - return new; -} - void kmem_cache_destroy_memcg_children(struct kmem_cache *s) { struct kmem_cache *c; @@ -3384,12 +3367,6 @@ void kmem_cache_destroy_memcg_children(struct kmem_cache *s) mutex_unlock(&activate_kmem_mutex); } -struct create_work { - struct mem_cgroup *memcg; - struct kmem_cache *cachep; - struct work_struct work; -}; - static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) { struct kmem_cache *cachep; @@ -3407,13 +3384,25 @@ static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) mutex_unlock(&memcg->slab_caches_mutex); } +struct create_work { + struct mem_cgroup *memcg; + struct kmem_cache *cachep; + struct work_struct work; +}; + static void memcg_create_cache_work_func(struct work_struct *w) { - struct create_work *cw; + struct create_work *cw = container_of(w, struct create_work, work); + struct mem_cgroup *memcg = cw->memcg; + struct kmem_cache *cachep = cw->cachep; + struct kmem_cache *new; - cw = container_of(w, struct create_work, work); - memcg_create_kmem_cache(cw->memcg, cw->cachep); - css_put(&cw->memcg->css); + new = kmem_cache_create_memcg(memcg, cachep->name, + cachep->object_size, cachep->align, + cachep->flags & ~SLAB_PANIC, cachep->ctor, cachep); + if (new) + new->allocflags |= __GFP_KMEMCG; + css_put(&memcg->css); kfree(cw); } diff --git a/mm/slab_common.c b/mm/slab_common.c index e77b51eb7347..11857abf7057 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -215,7 +215,10 @@ kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size, s->align = calculate_alignment(flags, align, size); s->ctor = ctor; - s->name = kstrdup(name, GFP_KERNEL); + if (memcg) + s->name = memcg_create_cache_name(memcg, parent_cache); + else + s->name = kstrdup(name, GFP_KERNEL); if (!s->name) goto out_free_cache; -- 2.30.2