From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752225AbaAPHqw (ORCPT ); Thu, 16 Jan 2014 02:46:52 -0500 Received: from mail-yh0-f54.google.com ([209.85.213.54]:38108 "EHLO mail-yh0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752037AbaAPHqr (ORCPT ); Thu, 16 Jan 2014 02:46:47 -0500 Date: Wed, 15 Jan 2014 23:46:44 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Andrew Morton cc: Johannes Weiner , Michal Hocko , KAMEZAWA Hiroyuki , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [patch v2 -mm] mm, oom: prefer thread group leaders for display purposes In-Reply-To: Message-ID: References: <20140116070549.GL6963@cmpxchg.org> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: 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 --- v2: fixes missing get_task_struct() found by Johannes. mm/memcontrol.c | 19 ++++++++++++------- mm/oom_kill.c | 12 ++++++++---- 2 files changed, 20 insertions(+), 11 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a815686..d69c4b3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1841,13 +1841,18 @@ 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; + get_task_struct(chosen); } 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);