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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> Precedence: bulk X-Mailing-List: bpf@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: <6f40c513-af3e-45b6-9000-c61494a23bd3@columbia.edu> 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