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[109.81.84.135]) by smtp.gmail.com with UTF8SMTPSA id a640c23a62f3a-ab78d5771easm947387866b.83.2025.02.11.12.35.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Feb 2025 12:35:48 -0800 (PST) Date: Tue, 11 Feb 2025 21:35:47 +0100 From: Michal Hocko To: Shakeel Butt Cc: Chen Ridong , hannes@cmpxchg.org, roman.gushchin@linux.dev, muchun.song@linux.dev, akpm@linux-foundation.org, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, chenridong@huawei.com, wangweiyang2@huawei.com Subject: Re: [PATCH] memcg: avoid dead loop when setting memory.max Message-ID: References: <20250211081819.33307-1-chenridong@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue 11-02-25 11:04:21, Shakeel Butt wrote: > On Tue, Feb 11, 2025 at 08:18:19AM +0000, Chen Ridong wrote: [...] > Wouldn't it be more robust if we put an upper bound on the else case of > above condition i.e. fix number of retries? As you have discovered there > is a hidden dependency on the forward progress of oom_reaper and this > check/code-path which I think is not needed. Any OOM path has a dependency on oom_reaper or task exiting. Is there any reason why this path should be any special? With cond_resched we can look for a day where this will be just removed and the code will still work. With a number of retries we will have a non-deterministic time dependent behavior because number of retries rather than fwd progress would define the failure mode. -- Michal Hocko SUSE Labs