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[109.81.94.245]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-49c609c602dsm3640220f8f.46.2026.11.13.00.20.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Nov 2026 00:20:00 -0800 (PST) Date: Fri, 13 Nov 2026 09:19:59 +0100 From: Michal Hocko To: Zhan Xusheng Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, penguin-kernel@i-love.sakura.ne.jp, tj@kernel.org, mkoutny@suse.com, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, zhanxusheng@xiaomi.com Subject: Re: [PATCH] mm: memcontrol: don't miss processes whose leader has exited in OOM scans Message-ID: References: <20261102114029.1259655-1-zhanxusheng1024@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261102114029.1259655-1-zhanxusheng1024@gmail.com> On Mon 02-11-26 19:40:29, Zhan Xusheng wrote: > Hi Michal, > > This is v1. v2 [1] reworked the check, but your questions apply to > both. > > On Mon, Nov 02, 2026 at 11:12:42AM +0100, Michal Hocko wrote: > > Is this a desirable/intended behavior? Shouldn't we move the dead leader > > along with the rest? > > Userspace sees it too. After writing the PID of such a process to > dst/cgroup.procs: > > src: cgroup.procs = 85 cgroup.threads = (empty) > dst: cgroup.procs = (empty) cgroup.threads = 86 87 > > Moving the leader would fix that, and memcg would then need no change, > as the PROCS walk already returns a dying leader with live threads. > The catch is that the leader has already gone through > cgroup_task_dead() and is still accounted by controllers: pids, for > one, uncharges it through task_css() when it is reaped, so the move > would also have to transfer its pids charge. Tejun, would that be > acceptable in the core? Do we have any conclusion on this? [...] > [1] https://lore.kernel.org/all/20261027144016.2582880-1-zhanxusheng1024@gmail.com/ > > Thanks, > Zhan Xusheng -- Michal Hocko SUSE Labs