From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f70.google.com (mail-wm0-f70.google.com [74.125.82.70]) by kanga.kvack.org (Postfix) with ESMTP id 835136B0260 for ; Fri, 12 Aug 2016 05:56:34 -0400 (EDT) Received: by mail-wm0-f70.google.com with SMTP id o80so2918219wme.1 for ; Fri, 12 Aug 2016 02:56:34 -0700 (PDT) Received: from mail-wm0-f66.google.com (mail-wm0-f66.google.com. [74.125.82.66]) by mx.google.com with ESMTPS id g19si1625645wmc.137.2016.08.12.02.56.29 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 12 Aug 2016 02:56:30 -0700 (PDT) Received: by mail-wm0-f66.google.com with SMTP id i138so1906777wmf.3 for ; Fri, 12 Aug 2016 02:56:29 -0700 (PDT) From: Michal Hocko Subject: [PATCH stable-4.4 3/3] mm: memcontrol: fix memcg id ref counter on swap charge move Date: Fri, 12 Aug 2016 11:56:19 +0200 Message-Id: <1470995779-10064-4-git-send-email-mhocko@kernel.org> In-Reply-To: <1470995779-10064-1-git-send-email-mhocko@kernel.org> References: <1470995779-10064-1-git-send-email-mhocko@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Stable tree , Johannes Weiner , Vladimir Davydov Cc: Andrew Morton , linux-mm@kvack.org, LKML , Vladimir Davydov , Linus Torvalds , Michal Hocko From: Vladimir Davydov commit 615d66c37c755c49ce022c9e5ac0875d27d2603d upstream. Since commit 73f576c04b94 ("mm: memcontrol: fix cgroup creation failure after many small jobs") 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") Link: http://lkml.kernel.org/r/9ce297c64954a42dc90b543bc76106c4a94f07e8.1470219853.git.vdavydov@virtuozzo.com Signed-off-by: Vladimir Davydov Acked-by: Michal Hocko Acked-by: Johannes Weiner Cc: [3.19+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Michal Hocko --- mm/memcontrol.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index dd6e2d24d9b1..d3e6e4fa61b8 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4136,9 +4136,9 @@ 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_online(struct mem_cgroup *memcg) @@ -4159,9 +4159,9 @@ static struct mem_cgroup *mem_cgroup_id_get_online(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; @@ -4170,6 +4170,16 @@ 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 @@ -4856,6 +4866,8 @@ 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. @@ -4863,9 +4875,9 @@ 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); -- 2.8.1 -- 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