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[109.81.86.79]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-3b79c4a2f03sm14103393f8f.72.2025.08.03.22.52.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 03 Aug 2025 22:52:12 -0700 (PDT) Date: Mon, 4 Aug 2025 07:52:10 +0200 From: Michal Hocko To: zhongjinji@honor.com Cc: linux-mm@kvack.org, akpm@linux-foundation.org, rientjes@google.com, shakeel.butt@linux.dev, npache@redhat.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, dvhart@infradead.org, dave@stgolabs.net, andrealmeid@igalia.com, liulu.liu@honor.com, feng.han@honor.com Subject: Re: [[PATCH v2] 2/2] futex: Only delay OOM reaper for processes using robust futex Message-ID: References: <20250801153649.23244-1-zhongjinji@honor.com> <20250801153649.23244-2-zhongjinji@honor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250801153649.23244-2-zhongjinji@honor.com> X-Stat-Signature: wzyew9ryf193cuxktkduh4it6msrzryh X-Rspamd-Queue-Id: 8F0BA140009 X-Rspamd-Server: rspam10 X-Rspam-User: X-HE-Tag: 1754286734-687215 X-HE-Meta: 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 dV6yBuov 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri 01-08-25 23:36:49, zhongjinji@honor.com wrote: > From: zhongjinji > > After merging the patch > https://lore.kernel.org/all/20220414144042.677008-1-npache@redhat.com/T/#u, > the OOM reaper runs less frequently because many processes exit within 2 seconds. > > However, when a process is killed, timely handling by the OOM reaper allows > its memory to be freed faster. > > Since relatively few processes use robust futex, delaying the OOM reaper for > all processes is undesirable, as many killed processes cannot release memory > more quickly. Could you elaborate more about why this is really needed? OOM should be a very slow path. Why do you care about this potential improvement in that situation? In other words what is the usecase? -- Michal Hocko SUSE Labs