From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by kanga.kvack.org (Postfix) with ESMTP id 561586B0276 for ; Wed, 11 Jul 2018 08:01:29 -0400 (EDT) Received: by mail-wr1-f69.google.com with SMTP id z13-v6so3188211wrq.3 for ; Wed, 11 Jul 2018 05:01:29 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id w198-v6sor476053wmw.56.2018.07.11.05.01.28 for (Google Transport Security); Wed, 11 Jul 2018 05:01:28 -0700 (PDT) From: 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> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: David Rientjes , Tetsuo Handa , linux-mm@kvack.org, LKML , Michal Hocko 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