Re: [patch 1/2] oom: remove oom_disable_count
From: Oleg Nesterov <oleg@redhat.com>
Date: 2011-08-30 15:32:31
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On 08/30, David Rientjes wrote:
This removes mm->oom_disable_count entirely since it's unnecessary and currently buggy. The counter was intended to be per-process but it's currently decremented in the exit path for each thread that exits, causing it to underflow. The count was originally intended to prevent oom killing threads that share memory with threads that cannot be killed since it doesn't lead to future memory freeing. The counter could be fixed to represent all threads sharing the same mm, but it's better to remove the count since: - it is possible that the OOM_DISABLE thread sharing memory with the victim is waiting on that thread to exit and will actually cause future memory freeing, and - there is no guarantee that a thread is disabled from oom killing just because another thread sharing its mm is oom disabled.
Great, thanks. Even _if_ (I hope not) we decide to re-introduce this counter later, I think it will be much more simple to start from the very beginning and make the correct patch.
quoted hunk ↗ jump to hunk
@@ -447,6 +431,9 @@ static int oom_kill_task(struct task_struct *p, struct mem_cgroup *mem) for_each_process(q) if (q->mm == mm && !same_thread_group(q, p) && !(q->flags & PF_KTHREAD)) {
(I guess this is on top of -mm patch)
+ if (q->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) + continue; +
Afaics, this is the only change apart from "removes mm->oom_disable_count entirely", looks reasonable to me. Oleg. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>