From 863fb410b57a2d7ac8ab066efbc840d5d4e621ae Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Thu, 23 Jan 2014 15:53:34 -0800 Subject: [PATCH] mm, oom: prefer thread group leaders for display purposes commit d49ad9355420c743c736bfd1dee9eaa5b1a7722a upstream. 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 Cc: Johannes Weiner Cc: Michal Hocko Cc: KAMEZAWA Hiroyuki Cc: Greg Thelen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Jiri Slaby --- 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 15429b92ff983..213d1b4aafd7d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1820,13 +1820,18 @@ 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 || 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 f5bed7f174635..a9b5b7ffc4768 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 || 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); -- 2.47.3