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[130.237.96.130]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5b8d857f7edsm1229650e87.31.2026.09.24.00.20.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Sep 2026 00:20:07 -0700 (PDT) Date: Thu, 24 Sep 2026 09:20:06 +0200 From: Klara Modin To: Baoquan He Cc: Chris Li , Rik van Riel , Gregory Price , Johannes Weiner , Nhat Pham , Kairui Song , Michal Hocko , Roman Gushchin , Shakeel Butt , Yosry Ahmed , David Hildenbrand , Muchun Song , Kemeng Shi , Barry Song , YoungJun Park , Chengming Zhou , "Lorenzo Stoakes (Oracle)" , "Liam R. Howlett" , "Vlastimil Babka (SUSE)" , Mike Rapoport , Suren =?utf-8?B?QmFnaGRhc2FyeWFu77+8?= , Qi Zheng , Axel Rasmussen , Yuanchu Xie , Wei Xu , Wenchao Hao , Jonathan Corbet , Hugh Dickins , Baolin Wang , Tejun Heo , Michal =?utf-8?Q?Koutn=C3=BD?= , Shuah Khan , Kunwu Chan , Meta kernel team , Linux Memory Management List , Linux Kernel Mailing List , linux-doc@vger.kernel.org, "open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" , Andrew Morton , Kairui Song , Joshua Hahn Subject: Re: Path forward for Virtualized Swap? Message-ID: References: <785353ef79844e81a8cd97e87b00ef1f785b15e5.camel@surriel.com> <83539be885f15bb567b30264f5f62e718f4a9fd0.camel@surriel.com> <5a7ad159b2fabf377b7e1fc4248c433287ac11fb.camel@surriel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 0D72F40006 X-Stat-Signature: amoibzak7dbygtkojrz7uracnwu9z8uq X-HE-Tag: 1790234409-948703 X-HE-Meta: U2FsdGVkX192w44jni+CD2RWcVj+7N3VqHBNHmPI6t0g1lDasElpgxp0kwmzTHXGBg9PMATSVsENsNJACwUqjiZphtOMMkD1m6p1m1F8wNMPBQa5pJhWY3HhkiF6goLA3miqzaq42j4QVrzIqzWmNNzTclroDKeApWDRM7pGPYjPPCARi5cPIu1xqx7m+7BPO6wtuD0gqcvP+h4UQXnOEJKIY7dINJgqqNdgSiwnEqvMlBAyGszpO2GzdwtsxbFMiO54JXaCEZPJhlwmfs1kTGHY5wP9ANoXbX2hhxHPJW84nUuj0WG0KSCdEtBceeOD3hui/lubV+6MRJVMSRTX//vdCIEwfXlLzW0Gt+f9Iq9Ey1zItxruliarE/i7MMsTbiMhqB+NzcHjDju6En/i3De8PvZVJbpFoDmrvbPKuCFV1oQcqQsh9Axc35IGAyVjT8fEW+XeWNsmVJDp3aiK+PxyG/Vo6F+UdpHOZewYOuP+IzyYnhl0KjDLvTbuAIfogEVbAJdzWkDrDUMdhe1ooaUv+Cav3raE16/uYDhRZftntub2HMLKP/rfiIx8SqftvUoJJlaVoQ0Y3Rt+5IRgCQVKvuQ7GYFz6WQhk0+vC3o5pQJIBK8wVLq5ORMP2r+Xwqw6zAF5XTMr9CTsiS2P+DgBfZiIMKoFm50Jtc+RbqhP48Jq/aKp4dV9da6O0hH6SIccZlVeywaFYAY1EpQ6YJd5zcTk+x5dXasCRiF/m1g8bXz9bhTI+odtSwDekGnYfm9/IrU7PVczwzoSAV4sYgBJowipc2R1Sgma0WJI2hSxzvZwBznkffu0wkXjjLmJXWJYYGVdIQEKjPNeeRw3Qj4n72rClAd4m5l4W3jVtAC4MGOQIFmAUHHIQWzjIiE6lLRFabG89yTfXxUyGU5XpokD5hiLoYuzTty1BIPOpdQLZCq3dTvzqwpuiMB5LBpZ/cSXl9XsoV+vDOaqKL1 ShGn0Ge2 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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 2026-09-24 13:51:50 +0800, Baoquan He wrote: > On 09/23/26 at 02:52pm, Klara Modin wrote: > > Hi, > > ... > > > > Chiming in as more of a user perspective. > > > > On my 4 GiB BPI-F3, I can reach more than 10:1 compression ratio on > > zswap during some parts when building GCC 17 snapshots. E.g: > > > > MemTotal: 3966864 kB > > SwapCached: 31872 kB > > SwapTotal: 16777212 kB > > SwapFree: 16638128 kB > > Zswap: 280140 kB > > Zswapped: 2859840 kB > > AnonPages: 2927376 kB > > AnonHugePages: 1409024 kB > > > > While this is 72 % rather than the 100 % you asked for, I think this > > shows that what size a potential limit on the uncompressed size of zswap > > is suitable heavily depends on the workload. > > > > I have been using vswap consistently on all my machines since about > > August, and I have also tried one or two versions of xswap (but the > > current lack of writeback makes it inconvenient for me). I really > > Thanks for testing xswap and reporting issue on xswap rfc v3. > > xswap has writeback now. I only built foundation for xswap, while > writeback part was left to other people for collaboration. Finally > I added it. > > [RFC PATCH 00/17] mm, swap: xswap writeback to a physical backend > https://lore.kernel.org/all/20260920072043.430390-1-hebaoquan@kylinos.cn/T/#u > Thanks, I'll give it another try when I have time. > > > appreciate the work being put in to decouple zswap from needing a > > physical swap device to work. > > ... > > > > My personal preference would be for a default uncapped (or very high, > > and I don't think 100 % of RAM is high) limit on the uncompressed data > > which is backed by zswap, since that would mean one less knob to tune. > > > > > > > > Chris > > > > Regards, > > Klara Modin