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[96.255.20.138]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-50744aef9e0sm46655051cf.30.2026.02.27.10.50.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 Feb 2026 10:50:42 -0800 (PST) Date: Fri, 27 Feb 2026 13:50:40 -0500 From: Gregory Price To: Shakeel Butt Cc: Matthew Wilcox , Kairui Song , lsf-pc@lists.linux-foundation.org, Axel Rasmussen , Yuanchu Xie , Wei Xu , linux-mm Subject: Re: [LSF/MM/BPF TOPIC] Improving MGLRU Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Stat-Signature: cpgkxb61efb4c8npp3zfhjxc6ukaactf X-Rspamd-Queue-Id: E90034000A X-Rspamd-Server: rspam03 X-HE-Tag: 1772218243-429089 X-HE-Meta: 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 bi5yEbxS bMR1SLVYqi7q6F7SsuBY5JHTb7Pbm94p3CCz35KFB5jfbjKfeYLMFAdHE/RtpzbUiTjHxSSUkk6QaNFuJVxempin6ExScr0W6/2VUFEUdrTARArZf0oun7XH16zk5U/FvC5DvMiUzzV5Fv2/CYaXEChqJl4DuXL4ZFuqOgao65Hy5ItUzGA5TNWlS8qHOivZkSAHh+agrQehLOdtYFm+0vobgI4Y1GQMdvyDGBSkrryYK/hAK8dQPHd/mMX7ZPPXGeufx+IdZdFSgDAbIPD+olEdBdUW5gu2Wc8U806jIqfBsR7tW7i0XB/XDDVvOISAihg3T4BXnQCyoIGk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Feb 27, 2026 at 09:55:52AM -0800, Shakeel Butt wrote: > On Thu, Feb 26, 2026 at 03:54:22PM +0000, Matthew Wilcox wrote: > > On Fri, Feb 20, 2026 at 01:25:33AM +0800, Kairui Song wrote: > > > MGLRU has been introduced in the mainline for years, but we still have two LRUs > > > today. There are many reasons MGLRU is still not the only LRU implementation in > > > the kernel. > > > > To my mind, the biggest problem with MGLRU is that Google dumped it on us > > and ran away. Commit 44958000bada claimed that it was now maintained and > > added three people as maintainers. In the six months since that commit, > > none of those three people have any commits in mm/! This is a shameful > > state of affairs. > > > > I say rip it out. > > I have very similar concerns. Though rather than ripping it out, I would like > we put efforts in unifying the two reclaim mechanism (traditional & MGLRU) over > improving MGLRU. > I would agree. If we could make the baseline MGLRU 2-generation and with behavioral parity with the current LRU, then adding the additional generations is just a mechanical change - and doesn't hurt anyone (default= 2 gen). But my understanding is MGLRU has behavior differences regarding its preferences on how it ages anon vs file. That mistake will cause significant pain in unifying them. ~Gregory