From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f179.google.com (mail-lb0-f179.google.com [209.85.217.179]) by kanga.kvack.org (Postfix) with ESMTP id 9F9076B006C for ; Mon, 2 Dec 2013 06:20:02 -0500 (EST) Received: by mail-lb0-f179.google.com with SMTP id l4so8215902lbv.24 for ; Mon, 02 Dec 2013 03:20:01 -0800 (PST) Received: from relay.parallels.com (relay.parallels.com. [195.214.232.42]) by mx.google.com with ESMTPS id yf5si18900181lab.107.2013.12.02.03.20.01 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 02 Dec 2013 03:20:01 -0800 (PST) From: Vladimir Davydov Subject: [PATCH v12 02/18] memcg: consolidate callers of memcg_cache_id Date: Mon, 2 Dec 2013 15:19:37 +0400 Message-ID: <1fc239729f563958c3200920af4e7845e2a6c798.1385974612.git.vdavydov@parallels.com> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: hannes@cmpxchg.org, mhocko@suse.cz, dchinner@redhat.com, akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, devel@openvz.org, glommer@openvz.org, vdavydov@parallels.com, Balbir Singh , 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 Signed-off-by: Vladimir Davydov Cc: Johannes Weiner Cc: Michal Hocko Cc: Balbir Singh 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 02b5176..144cb4c 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2960,6 +2960,30 @@ 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. */ @@ -2969,7 +2993,7 @@ 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 cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg)); + return cache_from_memcg_idx(cachep, memcg_cache_idx(p->memcg)); } #ifdef CONFIG_SLABINFO @@ -3067,18 +3091,6 @@ 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. * @@ -3240,7 +3252,7 @@ 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; @@ -3403,9 +3415,7 @@ 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 = cache_from_memcg_idx(cachep, idx); @@ -3578,10 +3588,9 @@ 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) + goto out; /* * 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