From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-gg0-f181.google.com (mail-gg0-f181.google.com [209.85.161.181]) by kanga.kvack.org (Postfix) with ESMTP id 43C166B0039 for ; Wed, 15 Jan 2014 21:40:53 -0500 (EST) Received: by mail-gg0-f181.google.com with SMTP id 21so712234ggh.26 for ; Wed, 15 Jan 2014 18:40:52 -0800 (PST) Received: from mail-yk0-x230.google.com (mail-yk0-x230.google.com [2607:f8b0:4002:c07::230]) by mx.google.com with ESMTPS id 21si2048986yhx.131.2014.01.15.18.40.47 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 15 Jan 2014 18:40:52 -0800 (PST) Received: by mail-yk0-f176.google.com with SMTP id 131so867460ykp.7 for ; Wed, 15 Jan 2014 18:40:46 -0800 (PST) Date: Wed, 15 Jan 2014 18:40:41 -0800 (PST) From: David Rientjes Subject: [patch -mm] mm, oom: prefer thread group leaders for display purposes Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , KAMEZAWA Hiroyuki , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org When two threads have the same badness score, it's preferable to kill the thread group leader so that the actual process name is printed to the kernel log rather than the thread group name which may be shared amongst several processes. This was the behavior when select_bad_process() used to do for_each_process(), but it now iterates threads instead and leads to ambiguity. Signed-off-by: David Rientjes --- mm/memcontrol.c | 18 +++++++++++------- mm/oom_kill.c | 12 ++++++++---- 2 files changed, 19 insertions(+), 11 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a815686..b482f49 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1841,13 +1841,17 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, break; }; points = oom_badness(task, memcg, NULL, totalpages); - if (points > chosen_points) { - if (chosen) - put_task_struct(chosen); - chosen = task; - chosen_points = points; - get_task_struct(chosen); - } + if (points < chosen_points) + continue; + /* Prefer thread group leaders for display purposes */ + if (points == chosen_points && + thread_group_leader(chosen)) + continue; + + if (chosen) + put_task_struct(chosen); + chosen = task; + chosen_points = points; } css_task_iter_end(&it); } diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 054ff47..1dca3d8 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -327,10 +327,14 @@ static struct task_struct *select_bad_process(unsigned int *ppoints, break; }; points = oom_badness(p, NULL, nodemask, totalpages); - if (points > chosen_points) { - chosen = p; - chosen_points = points; - } + if (points < chosen_points) + continue; + /* Prefer thread group leaders for display purposes */ + if (points == chosen_points && thread_group_leader(chosen)) + continue; + + chosen = p; + chosen_points = points; } if (chosen) get_task_struct(chosen); -- 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