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[158.94.182.130]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-89ecbba4bd0sm797206d6.11.2026.03.27.12.43.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 Mar 2026 12:43:38 -0700 (PDT) Date: Fri, 27 Mar 2026 14:43:34 -0500 From: Gregory Price To: Tal Zussman Cc: Matthew Wilcox , Axel Rasmussen , "Lorenzo Stoakes (Oracle)" , Michal Hocko , Andrew Morton , Shakeel Butt , lsf-pc@lists.linux-foundation.org, Johannes Weiner , David Hildenbrand , Qi Zheng , Chen Ridong , Emil Tsalapatis , Alexei Starovoitov , Yuanchu Xie , Wei Xu , Kairui Song , Nhat Pham , Barry Song <21cnbao@gmail.com>, David Stevens , Vernon Yang , David Rientjes , Kalesh Singh , wangzicheng , "T . J . Mercier" , Baolin Wang , Suren Baghdasaryan , Meta kernel team , bpf@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [LSF/MM/BPF TOPIC] Towards Unified and Extensible Memory Reclaim (reclaim_ext) Message-ID: References: <20260325210637.3704220-1-shakeel.butt@linux.dev> <20260325190547.abb7309fb63473b57b7a90a0@linux-foundation.org> <6f40c513-af3e-45b6-9000-c61494a23bd3@columbia.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6f40c513-af3e-45b6-9000-c61494a23bd3@columbia.edu> X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 12A3220008 X-Stat-Signature: xrim7bhz3qtx1gtdzoxx7ifgbe5j176d X-Rspam-User: X-HE-Tag: 1774640619-199883 X-HE-Meta: U2FsdGVkX1/pnQoo8XdLzXg7t8R2DxWUGGI/hil/QMPeIZU87SmjxsaWP67uqZr1kktRNk/UMsGjRoczHmmy88ueNE22w4Lgt4o4wFvdH0K1XXouOKawadpk62+83OftvzG3fAO9uYsxwmE16IW0/dj0OskUbiDAO8nwnppmEekph8v7wBHAkm0RufOOOvvUgPMnmnw0E3lLvTKLuhAo6zGWgCRanjZvE14N/1goiD3vBQjtEzTXg1gz5OYqD7pUh85Jwen7HREufmcJHCR7bhfWUAA0LmsOEgJdRHVaI87qkytP+FsvATBcy6ny6h+1r/JJJ4GgqKbKIUKDj4puL0wa1tfIdhsVzwscszZsjqqfULv5X9uNIA5AnnFkwuNsarFMY6JRp4waKF1G/dj/dWfvEudSwxynQivuCSrNGoOL0nWYx4Q//mxB/Qm0oZzMvaQzjiiLQHgLqu/DofpDQGV/1vFp8LiOSHbLsIRjQbHYHJ8JUBOzX6eRXS+cjOO3AT8+a6Uvv/ERK6LIBBbEL/Z9Z1wcN9dTrBbUyB0nplB/zg2ObZ0b3IuchczFId7S2/oWCfqA+5xQpIEvoSleYjeabD2XkaJFgT/Z+9ZzjC2pVquTa+tqjG47bKoKPGVs0Z2WDXtHHXybSocq1pILi9GjBH00GxFSv5PuRZ3JKmcNum1qZaWWknLhwWhMLbAG1FO8rVoOunWtaEeDORb3IiAORXo/0pyKgnBfDosgD0u8khdJvQUpe30sxTsYMEbkpq+qBJdqeVWOORiUsqHE7cDkbbQOk7eS29lJ9n4P0aXlTcmhc7smH7NOnQ1Yq6Kx+ya8iN/Iw2JK1f3wTGVFQ/uXSEVTDTiVsYPyIp+1OzKBtpbhKiUketb5LgNJttO+C7wjFdWrjbVKAK1dIsvi3d39teZ0ZHaVz0bxWrnLBR5lDgkwOb6rVuBYTrp4D84WGCzGB8UInq00dODnltc PI0nGgim 0fxPralhO0opF+K5OhN4rebeuZZz8egJv8XNRj7IFho9mDqz7z3LVt1Ak5Sp0X4ylubE8+ruor5AwGud24CF02EpZxkhSYo3McVzR2q/7lOLSAlyRtWzKqNIrUeW2G0wHQrcyPWMgmvTSjQdwBS7VXC+rZCLmJBqotjPB0DIrqsZi4eRv0KVN2XkyDmWVG+NJoGkHWxk/5p8mEItUuTdW9WhcYSojnQvuEE1NJBQnXTgOkHy5YRC8d4j4x/MkEYonMpyHSJ9SEx5yH+iNSAEpRbZlWHKLjWz1cljCcMNQ2DtC3zduNyVsr+tIrrvcGrHeq0W7qDHUUgW+CjJiOtk1HuXNyxxdfoAAgLxTqhxYUGBSEXvgVvAlu8VDJQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Mar 27, 2026 at 03:12:16PM -0400, Tal Zussman wrote: > > It's been well-known in the academic realm for a while that there isn't > really a "one-size-fits-all" policy that works *best* for all workloads. > Yes, you can make a general policy that works *well*, but if you really care > about a workload's performance and want to squeeze out the last 10-20% (or > more) of performance, you need to be able to (1) experiment and (2) take > advantage of application-level insights. Being able to extend reclaim (in > our case with eBPF) enables that. > This just makes me think going all the way to reclaim_ext and re-writing MGLRU as an eBPF extension in an effort to simplify the code/maintenance and keep what works working is the least-worst option. But this is a naive take, i'm sure making that interface stable would be even worse than just maintaining both LRU/MGLRU. ~Gregory