From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f69.google.com (mail-oi0-f69.google.com [209.85.218.69]) by kanga.kvack.org (Postfix) with ESMTP id B5B3A6B0253 for ; Tue, 2 Aug 2016 11:01:04 -0400 (EDT) Received: by mail-oi0-f69.google.com with SMTP id w207so368835026oiw.1 for ; Tue, 02 Aug 2016 08:01:04 -0700 (PDT) Received: from EUR01-HE1-obe.outbound.protection.outlook.com (mail-he1eur01on0120.outbound.protection.outlook.com. [104.47.0.120]) by mx.google.com with ESMTPS id h197si2110350oic.68.2016.08.02.08.01.02 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 02 Aug 2016 08:01:03 -0700 (PDT) From: Vladimir Davydov Subject: [PATCH v2 2/3] mm: memcontrol: fix memcg id ref counter on swap charge move Date: Tue, 2 Aug 2016 18:00:49 +0300 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: stable@vger.kernel.org, Johannes Weiner , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org Since commit 73f576c04b941 swap entries do not pin memcg->css.refcnt directly. Instead, they pin memcg->id.ref. So we should adjust the reference counters accordingly when moving swap charges between cgroups. Fixes: 73f576c04b941 ("mm: memcontrol: fix cgroup creation failure after many small jobs") Signed-off-by: Vladimir Davydov Acked-by: Michal Hocko Cc: [3.19+] --- mm/memcontrol.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4ae12effe347..67109d556a4a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4031,9 +4031,9 @@ static struct cftype mem_cgroup_legacy_files[] = { static DEFINE_IDR(mem_cgroup_idr); -static void mem_cgroup_id_get(struct mem_cgroup *memcg) +static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n) { - atomic_inc(&memcg->id.ref); + atomic_add(n, &memcg->id.ref); } static struct mem_cgroup *mem_cgroup_id_get_active(struct mem_cgroup *memcg) @@ -4054,9 +4054,9 @@ static struct mem_cgroup *mem_cgroup_id_get_active(struct mem_cgroup *memcg) return memcg; } -static void mem_cgroup_id_put(struct mem_cgroup *memcg) +static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n) { - if (atomic_dec_and_test(&memcg->id.ref)) { + if (atomic_sub_and_test(n, &memcg->id.ref)) { idr_remove(&mem_cgroup_idr, memcg->id.id); memcg->id.id = 0; @@ -4065,6 +4065,16 @@ static void mem_cgroup_id_put(struct mem_cgroup *memcg) } } +static inline void mem_cgroup_id_get(struct mem_cgroup *memcg) +{ + mem_cgroup_id_get_many(memcg, 1); +} + +static inline void mem_cgroup_id_put(struct mem_cgroup *memcg) +{ + mem_cgroup_id_put_many(memcg, 1); +} + /** * mem_cgroup_from_id - look up a memcg from a memcg id * @id: the memcg id to look up @@ -4699,6 +4709,8 @@ static void __mem_cgroup_clear_mc(void) if (!mem_cgroup_is_root(mc.from)) page_counter_uncharge(&mc.from->memsw, mc.moved_swap); + mem_cgroup_id_put_many(mc.from, mc.moved_swap); + /* * we charged both to->memory and to->memsw, so we * should uncharge to->memory. @@ -4706,9 +4718,9 @@ static void __mem_cgroup_clear_mc(void) if (!mem_cgroup_is_root(mc.to)) page_counter_uncharge(&mc.to->memory, mc.moved_swap); - css_put_many(&mc.from->css, mc.moved_swap); + mem_cgroup_id_get_many(mc.to, mc.moved_swap); + css_put_many(&mc.to->css, mc.moved_swap); - /* we've already done css_get(mc.to) */ mc.moved_swap = 0; } memcg_oom_recover(from); -- 2.1.4 -- 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