From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED36BC5CFE7 for ; Wed, 11 Jul 2018 12:01:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 956D320BEC for ; Wed, 11 Jul 2018 12:01:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 956D320BEC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732583AbeGKMF3 (ORCPT ); Wed, 11 Jul 2018 08:05:29 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:34943 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726269AbeGKMF3 (ORCPT ); Wed, 11 Jul 2018 08:05:29 -0400 Received: by mail-wm0-f67.google.com with SMTP id v3-v6so2282832wmh.0 for ; Wed, 11 Jul 2018 05:01:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=p+DsmytoCm1k5u6GKbImO3pLjQkmS1zMYiXb5ppcJos=; b=M9mRlzOmv+UCYu7rrxiCGFHfq7W7nN871GDoYV16foqp/YM8SZogIOQdDyoJ6fgds1 sB1oMhSJjstb4YjVwt0reBWtIKjA6+7uKjyc45LVYUyvRlMUCSRWlrmuEIxm/O8KNyDw wSYsP/AIBd8V7j/7Jf8/8D2u1q2xY8X4pREKr1SvolX+XjSLiLtD0uif06JXJ9Scd1F6 XfZ5HPjdGWMZD71iHWQInus6m2Zb7J0xdgFh3dIIEdhxsrO8FWboSnMSd9mfzYUr/RY0 X5cpH/thZbWpuznyyMe28lAAKeEmBuyU3SQswM7eaolelOpiVad+bSKYKrAcq4nrCW0G n2JQ== X-Gm-Message-State: APt69E1Yz4BfbAUEC2hzIXnVyjJZiHYAjNz9ZR/mWUX7Cq+3vBgJvf2M Qa+KVbd/mHYaQkIFJj1L70o= X-Google-Smtp-Source: AAOMgpfk5UJeLjFCZWC64ocX3SI6NT6jLNlUoXNj0GRrUKWGLAAkMRuvKNwSLMmfCkRnEk9iFpK2lg== X-Received: by 2002:a1c:b94c:: with SMTP id j73-v6mr18623025wmf.104.1531310487918; Wed, 11 Jul 2018 05:01:27 -0700 (PDT) Received: from tiehlicka.suse.cz (ip-37-188-144-122.eurotel.cz. [37.188.144.122]) by smtp.gmail.com with ESMTPSA id j11-v6sm20749703wrr.37.2018.07.11.05.01.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 11 Jul 2018 05:01:27 -0700 (PDT) From: Michal Hocko To: Andrew Morton Cc: David Rientjes , Tetsuo Handa , , LKML , Michal Hocko Subject: [PATCH] mm, oom: document oom_lock Date: Wed, 11 Jul 2018 14:01:21 +0200 Message-Id: <20180711120121.25635-1-mhocko@kernel.org> X-Mailer: git-send-email 2.18.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michal Hocko Add a short documentation about what is the oom_lock scope. Requested-by: David Rientjes Signed-off-by: Michal Hocko --- mm/oom_kill.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index ed9d473c571e..32e6f7becb40 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -53,6 +53,14 @@ int sysctl_panic_on_oom; int sysctl_oom_kill_allocating_task; int sysctl_oom_dump_tasks = 1; +/* + * Serializes oom killer invocations (out_of_memory()) from all contexts to + * prevent from over eager oom killing (e.g. when the oom killer is invoked + * from different domains). + * + * oom_killer_disable() relies on this lock to stabilize oom_killer_disabled + * and mark_oom_victim + */ DEFINE_MUTEX(oom_lock); #ifdef CONFIG_NUMA -- 2.18.0