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Thu, 26 Mar 2026 13:30:49 -0700 (PDT) Received: from gourry-fedora-PF4VCD3F ([2620:10d:c091:500::2:e5e8]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8d00e4ca250sm323370585a.25.2026.03.26.13.30.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Mar 2026 13:30:48 -0700 (PDT) Date: Thu, 26 Mar 2026 15:30:46 -0500 From: Gregory Price To: Axel Rasmussen Cc: "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 , Matthew Wilcox , 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: 6438bgq8jkoeeusti7oanog8qq9cez7c X-Rspamd-Queue-Id: 43FFA1C000E X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1774557050-874635 X-HE-Meta: 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 LzR03GTG 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Mar 26, 2026 at 01:02:02PM -0700, Axel Rasmussen wrote: > > I think one thing we all agree on at least is, long term, there isn't > really a good argument for having > 1 LRU implementation. E.g., we > don't believe there are just irreconcilable differences, where one > impl is better for some workloads, and another is better for others, > and there is no way the two can be converged. > I absolutely believe there are irreconcilable differences - but not in the sense that one is better or worse, but in the sense that features from one cannot work in the other. > - My sense is MGLRU is "close", meaning as Kairui said in "average" > cases it is substantially better, and the gaps are both fairly narrow > / edge-casey, and very solveable. > This is a really, really bold claim. So much of this is workload dependent, and LRU has decades of battle-testing while MGLRU has barely been around 4 years. ~Gregory