[PATCH] mm,oom: don't kill children of oom_task_origin() process.

[Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>]

Selecting a child of the candidate which was chosen by oom_task_origin()
is pointless. We want to kill the candidate first.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 mm/oom_kill.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 28d6a32..703537a2 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -697,6 +697,14 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 	if (__ratelimit(&oom_rs))
 		dump_header(oc, p, memcg);
 
+	/*
+	 * We must send SEGKILL on p rather than p's children in order to make
+	 * sure that oom_task_origin(p) becomes false. Printing the score value
+	 * which is (ULONG_MAX * 1000 / totalpages) is useless for this case.
+	 */
+	if (oom_task_origin(p))
+		goto kill;
+
 	pr_err("%s: Kill process %d (%s) score %u or sacrifice child\n",
 		message, task_pid_nr(p), p->comm, points);
 
@@ -728,6 +736,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 	}
 	read_unlock(&tasklist_lock);
 
+ kill:
 	p = find_lock_task_mm(victim);
 	if (!p) {
 		put_task_struct(victim);
-- 
1.8.3.1

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