From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-f71.google.com (mail-io1-f71.google.com [209.85.166.71]) by kanga.kvack.org (Postfix) with ESMTP id 078EA8E0038 for ; Tue, 8 Jan 2019 09:21:40 -0500 (EST) Received: by mail-io1-f71.google.com with SMTP id k4so3350271ioc.10 for ; Tue, 08 Jan 2019 06:21:40 -0800 (PST) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [202.181.97.72]) by mx.google.com with ESMTPS id n128si6999665itc.40.2019.01.08.06.21.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 08 Jan 2019 06:21:38 -0800 (PST) Subject: [PATCH 3/2] memcg: Facilitate termination of memcg OOM victims. References: <20190107143802.16847-1-mhocko@kernel.org> From: Tetsuo Handa Message-ID: Date: Tue, 8 Jan 2019 23:21:23 +0900 MIME-Version: 1.0 In-Reply-To: <20190107143802.16847-1-mhocko@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko , linux-mm@kvack.org Cc: Johannes Weiner , Andrew Morton , LKML From: Tetsuo Handa If memcg OOM events in different domains are pending, already OOM-killed threads needlessly wait for pending memcg OOM events in different domains. An out_of_memory() call is slow because it involves printk(). With slow serial consoles, out_of_memory() might take more than a second. Therefore, allowing killed processes to quickly call mmput() from exit_mm() from do_exit() will help calling __mmput() (which can reclaim more memory than the OOM reaper can reclaim) quickly. Signed-off-by: Tetsuo Handa --- mm/memcontrol.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 90eb2e2..a7d3ba9 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1389,14 +1389,19 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, }; bool ret = true; - mutex_lock(&oom_lock); - /* - * multi-threaded tasks might race with oom_reaper and gain - * MMF_OOM_SKIP before reaching out_of_memory which can lead - * to out_of_memory failure if the task is the last one in - * memcg which would be a false possitive failure reported + * Multi-threaded tasks might race with oom_reaper() and gain + * MMF_OOM_SKIP before reaching out_of_memory(). But if current + * thread was already killed or is ready to terminate, there is + * no need to call out_of_memory() nor wait for oom_reaoer() to + * set MMF_OOM_SKIP. These three checks minimize possibility of + * needlessly calling out_of_memory() and try to call exit_mm() + * as soon as possible. */ + if (mutex_lock_killable(&oom_lock)) + return true; + if (fatal_signal_pending(current)) + goto unlock; if (tsk_is_oom_victim(current)) goto unlock; -- 1.8.3.1