Re: [PATCH] mm,oom: don't kill children of oom_task_origin() process.
From: Michal Hocko <hidden>
Date: 2016-02-22 11:39:36
On Sat 20-02-16 13:54:02, Tetsuo Handa wrote:
Selecting a child of the candidate which was chosen by oom_task_origin() is pointless. We want to kill the candidate first.
NACK, until we see a clear evidence that there is a real application which triggers ksm/swapoff from a context where this would make a difference. There is no good reason to add new checks to an already subtle code just for something that even doesn't matter in the real life.
quoted hunk ↗ jump to hunk
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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
-- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>