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Tue, 14 Mar 2023 03:07:47 -0700 (PDT) Message-ID: Date: Tue, 14 Mar 2023 18:07:42 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH RESEND] mm/oom_kill: don't kill exiting tasks in oom_kill_memcg_member To: Michal Hocko Cc: shakeelb@google.com, hannes@cmpxchg.org, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20230314091136.264878-1-haifeng.xu@shopee.com> From: Haifeng Xu In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: f4pgp4t1h9fbkzfe696xt7pg3ti3xdcr X-Rspam-User: X-Rspamd-Queue-Id: 6296C40005 X-Rspamd-Server: rspam06 X-HE-Tag: 1678788469-730352 X-HE-Meta: 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 f+hp31g9 e+QBS6B9Sy5KsfVVcO3eKJvD3opzA45a6eRIB/pQDJr5l1BwgHcR/or1QTfctFHyu+6t9+F6zWVUj9oyaUsUkL1Y8gXqy4ee36UKf1vqXl+qTbi368jcPtEu+iXbtkfDcMoKkLVXwJi8gvpmTK7/18h026Wg2wU3yu6oF7gfqbmzD4fxYPCT5PcoqURJQXmMvZtlKqmDlFhyxkyQERHonfjbhgoBhUPu/iOCtkMk8BApxBOHe/YZP3SeCzxuGdj6P7/l6S4QgPOpz1jt/iGKvc7oetOZclP+yu7K4asbwDqrKtn7rbqwDN/46v2isRwwdjjbwE+DXg2ju+vTJ+qpulN9/kdT98EtJHGMXSROwfphixVKmIOjpM5GoR5efzKeDgnacw95Yme7Mx/9+ewvuRL2bz8c6i2Aqa2eY X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2023/3/14 17:19, Michal Hocko wrote: > On Tue 14-03-23 09:11:36, Haifeng Xu wrote: >> If oom_group is set, oom_kill_process() invokes oom_kill_memcg_member() >> to kill all processes in the memcg. When scanning tasks in memcg, maybe >> the provided task is marked as oom victim. Also, some tasks are likely >> to release their address space. There is no need to kill the exiting tasks. > > This doesn't state any actual problem. Could you be more specific? Is > this a bug fix, a behavior change or an optimization? 1) oom_kill_process() has inovked __oom_kill_process() to kill the selected victim, but it will be scanned in mem_cgroup_scan_tasks(). It's pointless to kill the victim twice. 2) for those exiting processes, reaping them directly is also a faster way to free memory compare with invoking __oom_kill_process().