mm, oom: prefer thread group leaders for display purposes (d49ad935) · Commits · 戴 / test

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>

mm/memcontrol.c

+12 −7

Original line number	Diff line number	Diff line
		@@ -1841,14 +1841,19 @@ 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 (!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);
		}

mm/oom_kill.c

+8 −4

Original line number	Diff line number	Diff line
		@@ -327,11 +327,15 @@ static struct task_struct select_bad_process(unsigned int ppoints,
		break;
		};
		points = oom_badness(p, NULL, nodemask, totalpages);
		if (points > chosen_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);
		rcu_read_unlock();

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