From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f46.google.com (mail-pb0-f46.google.com [209.85.160.46]) by kanga.kvack.org (Postfix) with ESMTP id AD3A46B00DF for ; Thu, 24 Oct 2013 08:05:22 -0400 (EDT) Received: by mail-pb0-f46.google.com with SMTP id un1so2509487pbc.33 for ; Thu, 24 Oct 2013 05:05:22 -0700 (PDT) Received: from psmtp.com ([74.125.245.169]) by mx.google.com with SMTP id it5si802707pbc.185.2013.10.24.05.05.20 for ; Thu, 24 Oct 2013 05:05:21 -0700 (PDT) From: Vladimir Davydov Subject: [PATCH v11 02/15] memcg: consolidate callers of memcg_cache_id Date: Thu, 24 Oct 2013 16:04:53 +0400 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: glommer@openvz.org, khorenko@parallels.com, devel@openvz.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Johannes Weiner , Michal Hocko , Kamezawa Hiroyuki From: Glauber Costa Each caller of memcg_cache_id ends up sanitizing its parameters in its own way. Now that the memcg_cache_id itself is more robust, we can consolidate this. Also, as suggested by Michal, a special helper memcg_cache_idx is used when the result is expected to be used directly as an array index to make sure we never accesses in a negative index. Signed-off-by: Glauber Costa Cc: Johannes Weiner Cc: Michal Hocko Cc: Kamezawa Hiroyuki --- mm/memcontrol.c | 49 +++++++++++++++++++++++++++++-------------------- 1 file changed, 29 insertions(+), 20 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 0712277..0a5cc30 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2937,6 +2937,30 @@ static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg) } /* + * helper for acessing a memcg's index. It will be used as an index in the + * child cache array in kmem_cache, and also to derive its name. This function + * will return -1 when this is not a kmem-limited memcg. + */ +int memcg_cache_id(struct mem_cgroup *memcg) +{ + if (!memcg || !memcg_can_account_kmem(memcg)) + return -1; + return memcg->kmemcg_id; +} + +/* + * This helper around memcg_cache_id is not intented for use outside memcg + * core. It is meant for places where the cache id is used directly as an array + * index + */ +static int memcg_cache_idx(struct mem_cgroup *memcg) +{ + int ret = memcg_cache_id(memcg); + BUG_ON(ret < 0); + return ret; +} + +/* * This is a bit cumbersome, but it is rarely used and avoids a backpointer * in the memcg_cache_params struct. */ @@ -2946,7 +2970,7 @@ static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p) VM_BUG_ON(p->is_root_cache); cachep = p->root_cache; - return cachep->memcg_params->memcg_caches[memcg_cache_id(p->memcg)]; + return cachep->memcg_params->memcg_caches[memcg_cache_idx(p->memcg)]; } #ifdef CONFIG_SLABINFO @@ -3051,18 +3075,6 @@ void memcg_cache_list_add(struct mem_cgroup *memcg, struct kmem_cache *cachep) } /* - * helper for acessing a memcg's index. It will be used as an index in the - * child cache array in kmem_cache, and also to derive its name. This function - * will return -1 when this is not a kmem-limited memcg. - */ -int memcg_cache_id(struct mem_cgroup *memcg) -{ - if (!memcg || !memcg_can_account_kmem(memcg)) - return -1; - return memcg->kmemcg_id; -} - -/* * This ends up being protected by the set_limit mutex, during normal * operation, because that is its main call site. * @@ -3224,7 +3236,7 @@ void memcg_release_cache(struct kmem_cache *s) goto out; memcg = s->memcg_params->memcg; - id = memcg_cache_id(memcg); + id = memcg_cache_idx(memcg); root = s->memcg_params->root_cache; root->memcg_params->memcg_caches[id] = NULL; @@ -3387,9 +3399,7 @@ static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, struct kmem_cache *new_cachep; int idx; - BUG_ON(!memcg_can_account_kmem(memcg)); - - idx = memcg_cache_id(memcg); + idx = memcg_cache_idx(memcg); mutex_lock(&memcg_cache_mutex); new_cachep = cachep->memcg_params->memcg_caches[idx]; @@ -3562,10 +3572,9 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, rcu_read_lock(); memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner)); - if (!memcg_can_account_kmem(memcg)) - goto out; - idx = memcg_cache_id(memcg); + if (idx < 0) + return cachep; /* * barrier to mare sure we're always seeing the up to date value. The -- 1.7.10.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org