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From: Michal Hocko <mhocko@suse.com>
To: Chen Ridong <chenridong@huaweicloud.com>
Cc: akpm@linux-foundation.org, hannes@cmpxchg.org,
	yosryahmed@google.com, roman.gushchin@linux.dev,
	shakeel.butt@linux.dev, muchun.song@linux.dev, davidf@vimeo.com,
	vbabka@suse.cz, handai.szj@taobao.com, rientjes@google.com,
	kamezawa.hiroyu@jp.fujitsu.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
	chenridong@huawei.com, wangweiyang2@huawei.com
Subject: Re: [PATCH v1] memcg: fix soft lockup in the OOM process
Date: Tue, 17 Dec 2024 13:54:35 +0100	[thread overview]
Message-ID: <Z2F0ixNUW6kah1pQ@tiehlicka> (raw)
In-Reply-To: <20241217121828.3219752-1-chenridong@huaweicloud.com>

On Tue 17-12-24 12:18:28, Chen Ridong wrote:
[...]
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index 1c485beb0b93..14260381cccc 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -390,6 +390,7 @@ static int dump_task(struct task_struct *p, void *arg)
>  	if (!is_memcg_oom(oc) && !oom_cpuset_eligible(p, oc))
>  		return 0;
>  
> +	cond_resched();
>  	task = find_lock_task_mm(p);
>  	if (!task) {
>  		/*

This is called from RCU read lock for the global OOM killer path and I
do not think you can schedule there. I do not remember specifics of task
traversal for crgoup path but I guess that you might need to silence the
soft lockup detector instead or come up with a different iteration
scheme.
-- 
Michal Hocko
SUSE Labs


  reply	other threads:[~2024-12-17 12:54 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-17 12:18 Chen Ridong
2024-12-17 12:54 ` Michal Hocko [this message]
2024-12-18  7:44   ` Chen Ridong
2024-12-18  7:56     ` Michal Hocko
2024-12-18  9:00       ` Chen Ridong
2024-12-18 10:22         ` Michal Hocko
2024-12-19  1:27           ` Chen Ridong
2024-12-19  7:57             ` Michal Hocko
2024-12-20 10:44               ` Chen Ridong

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