mm, oom: prefer thread group leaders for display purposes

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 <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Rientjes 2014-01-23 15:53:34 -08:00 committed by Linus Torvalds
parent c3ac14b267
commit d49ad93554
2 changed files with 20 additions and 11 deletions

View File

@ -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 || 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);
}

View File

@ -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);