From 794b1248be4e7e157f5535c3ee49168aa4643349 Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Mon, 7 Apr 2014 15:39:26 -0700 Subject: [PATCH] memcg, slab: separate memcg vs root cache creation paths Memcg-awareness turned kmem_cache_create() into a dirty interweaving of memcg-only and except-for-memcg calls. To clean this up, let's move the code responsible for memcg cache creation to a separate function. 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 | 6 -- include/linux/slab.h | 6 +- mm/memcontrol.c | 7 +- mm/slab_common.c | 191 +++++++++++++++++++++---------------- 4 files changed, 113 insertions(+), 97 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index ab7f02884983..02d3072841e9 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -638,12 +638,6 @@ 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/include/linux/slab.h b/include/linux/slab.h index b5b2df60299e..3dd389aa91c7 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -115,9 +115,9 @@ int slab_is_available(void); struct kmem_cache *kmem_cache_create(const char *, size_t, size_t, unsigned long, void (*)(void *)); -struct kmem_cache * -kmem_cache_create_memcg(struct mem_cgroup *, const char *, size_t, size_t, - unsigned long, void (*)(void *), struct kmem_cache *); +#ifdef CONFIG_MEMCG_KMEM +void kmem_cache_create_memcg(struct mem_cgroup *, struct kmem_cache *); +#endif void kmem_cache_destroy(struct kmem_cache *); int kmem_cache_shrink(struct kmem_cache *); void kmem_cache_free(struct kmem_cache *, void *); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 32c7342df4bf..451523c3bd4e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3395,13 +3395,8 @@ static void memcg_create_cache_work_func(struct work_struct *w) 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; - 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; + kmem_cache_create_memcg(memcg, cachep); css_put(&memcg->css); kfree(cw); } diff --git a/mm/slab_common.c b/mm/slab_common.c index 11857abf7057..ccc012f00126 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -29,8 +29,7 @@ DEFINE_MUTEX(slab_mutex); struct kmem_cache *kmem_cache; #ifdef CONFIG_DEBUG_VM -static int kmem_cache_sanity_check(struct mem_cgroup *memcg, const char *name, - size_t size) +static int kmem_cache_sanity_check(const char *name, size_t size) { struct kmem_cache *s = NULL; @@ -57,13 +56,7 @@ static int kmem_cache_sanity_check(struct mem_cgroup *memcg, const char *name, } #if !defined(CONFIG_SLUB) || !defined(CONFIG_SLUB_DEBUG_ON) - /* - * For simplicity, we won't check this in the list of memcg - * caches. We have control over memcg naming, and if there - * aren't duplicates in the global list, there won't be any - * duplicates in the memcg lists as well. - */ - if (!memcg && !strcmp(s->name, name)) { + if (!strcmp(s->name, name)) { pr_err("%s (%s): Cache name already exists.\n", __func__, name); dump_stack(); @@ -77,8 +70,7 @@ static int kmem_cache_sanity_check(struct mem_cgroup *memcg, const char *name, return 0; } #else -static inline int kmem_cache_sanity_check(struct mem_cgroup *memcg, - const char *name, size_t size) +static inline int kmem_cache_sanity_check(const char *name, size_t size) { return 0; } @@ -139,6 +131,46 @@ unsigned long calculate_alignment(unsigned long flags, return ALIGN(align, sizeof(void *)); } +static struct kmem_cache * +do_kmem_cache_create(char *name, size_t object_size, size_t size, size_t align, + unsigned long flags, void (*ctor)(void *), + struct mem_cgroup *memcg, struct kmem_cache *root_cache) +{ + struct kmem_cache *s; + int err; + + err = -ENOMEM; + s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); + if (!s) + goto out; + + s->name = name; + s->object_size = object_size; + s->size = size; + s->align = align; + s->ctor = ctor; + + err = memcg_alloc_cache_params(memcg, s, root_cache); + if (err) + goto out_free_cache; + + err = __kmem_cache_create(s, flags); + if (err) + goto out_free_cache; + + s->refcount = 1; + list_add(&s->list, &slab_caches); + memcg_register_cache(s); +out: + if (err) + return ERR_PTR(err); + return s; + +out_free_cache: + memcg_free_cache_params(s); + kfree(s); + goto out; +} /* * kmem_cache_create - Create a cache. @@ -164,34 +196,21 @@ unsigned long calculate_alignment(unsigned long flags, * cacheline. This can be beneficial if you're counting cycles as closely * as davem. */ - struct kmem_cache * -kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size, - size_t align, unsigned long flags, void (*ctor)(void *), - struct kmem_cache *parent_cache) +kmem_cache_create(const char *name, size_t size, size_t align, + unsigned long flags, void (*ctor)(void *)) { - struct kmem_cache *s = NULL; + struct kmem_cache *s; + char *cache_name; int err; get_online_cpus(); mutex_lock(&slab_mutex); - err = kmem_cache_sanity_check(memcg, name, size); + err = kmem_cache_sanity_check(name, size); if (err) goto out_unlock; - if (memcg) { - /* - * Since per-memcg caches are created asynchronously on first - * allocation (see memcg_kmem_get_cache()), several threads can - * try to create the same cache, but only one of them may - * succeed. Therefore if we get here and see the cache has - * already been created, we silently return NULL. - */ - if (cache_from_memcg_idx(parent_cache, memcg_cache_id(memcg))) - goto out_unlock; - } - /* * Some allocators will constraint the set of valid flags to a subset * of all flags. We expect them to define CACHE_CREATE_MASK in this @@ -200,55 +219,29 @@ kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size, */ flags &= CACHE_CREATE_MASK; - if (!memcg) { - s = __kmem_cache_alias(name, size, align, flags, ctor); - if (s) - goto out_unlock; - } - - err = -ENOMEM; - s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); - if (!s) + s = __kmem_cache_alias(name, size, align, flags, ctor); + if (s) goto out_unlock; - s->object_size = s->size = size; - s->align = calculate_alignment(flags, align, size); - s->ctor = ctor; + cache_name = kstrdup(name, GFP_KERNEL); + if (!cache_name) { + err = -ENOMEM; + goto out_unlock; + } - 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; - - err = memcg_alloc_cache_params(memcg, s, parent_cache); - if (err) - goto out_free_cache; - - err = __kmem_cache_create(s, flags); - if (err) - goto out_free_cache; - - s->refcount = 1; - list_add(&s->list, &slab_caches); - memcg_register_cache(s); + s = do_kmem_cache_create(cache_name, size, size, + calculate_alignment(flags, align, size), + flags, ctor, NULL, NULL); + if (IS_ERR(s)) { + err = PTR_ERR(s); + kfree(cache_name); + } out_unlock: mutex_unlock(&slab_mutex); put_online_cpus(); if (err) { - /* - * There is no point in flooding logs with warnings or - * especially crashing the system if we fail to create a cache - * for a memcg. In this case we will be accounting the memcg - * allocation to the root cgroup until we succeed to create its - * own cache, but it isn't that critical. - */ - if (!memcg) - return NULL; - if (flags & SLAB_PANIC) panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n", name, err); @@ -260,22 +253,56 @@ out_unlock: return NULL; } return s; - -out_free_cache: - memcg_free_cache_params(s); - kfree(s->name); - kmem_cache_free(kmem_cache, s); - goto out_unlock; -} - -struct kmem_cache * -kmem_cache_create(const char *name, size_t size, size_t align, - unsigned long flags, void (*ctor)(void *)) -{ - return kmem_cache_create_memcg(NULL, name, size, align, flags, ctor, NULL); } EXPORT_SYMBOL(kmem_cache_create); +#ifdef CONFIG_MEMCG_KMEM +/* + * kmem_cache_create_memcg - Create a cache for a memory cgroup. + * @memcg: The memory cgroup the new cache is for. + * @root_cache: The parent of the new cache. + * + * This function attempts to create a kmem cache that will serve allocation + * requests going from @memcg to @root_cache. The new cache inherits properties + * from its parent. + */ +void kmem_cache_create_memcg(struct mem_cgroup *memcg, struct kmem_cache *root_cache) +{ + struct kmem_cache *s; + char *cache_name; + + get_online_cpus(); + mutex_lock(&slab_mutex); + + /* + * Since per-memcg caches are created asynchronously on first + * allocation (see memcg_kmem_get_cache()), several threads can try to + * create the same cache, but only one of them may succeed. + */ + if (cache_from_memcg_idx(root_cache, memcg_cache_id(memcg))) + goto out_unlock; + + cache_name = memcg_create_cache_name(memcg, root_cache); + if (!cache_name) + goto out_unlock; + + s = do_kmem_cache_create(cache_name, root_cache->object_size, + root_cache->size, root_cache->align, + root_cache->flags, root_cache->ctor, + memcg, root_cache); + if (IS_ERR(s)) { + kfree(cache_name); + goto out_unlock; + } + + s->allocflags |= __GFP_KMEMCG; + +out_unlock: + mutex_unlock(&slab_mutex); + put_online_cpus(); +} +#endif /* CONFIG_MEMCG_KMEM */ + void kmem_cache_destroy(struct kmem_cache *s) { /* Destroy all the children caches if we aren't a memcg cache */