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Tue, 22 Sep 2026 07:30:20 -0700 (PDT) Date: Tue, 22 Sep 2026 10:30:19 -0400 From: Johannes Weiner To: Chris Li Cc: Baoquan He , linux-mm@kvack.org, akpm@linux-foundation.org, kasong@tencent.com, nphamcs@gmail.com, baohua@kernel.org, youngjun.park@lge.com, david@kernel.org, kunwu.chan@gmail.com, baoquan.he@linux.dev, gourry@gourry.net, riel@surriel.com, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev Subject: Re: [RFC PATCH 00/17] mm, swap: xswap writeback to a physical backend Message-ID: References: <20260920072043.430390-1-hebaoquan@kylinos.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: C8EE940012 X-Stat-Signature: kkf3ugrgx4o47ociaxjdk3nmmbed4kbt X-HE-Tag: 1790087421-191118 X-HE-Meta: U2FsdGVkX1+eM5cysyDxLDS2fizsK1Jw7h+oP3VBWmhNnPVZlaNXx84at5k2z8dIKJHe/ngOkUbjkOwjreluSU0lHWj23rw8U2Imx0DYBAENss8H4SdvrCtbW28XDIg6DcDjgNPh+RotnznPPDPhs1gVuAAeELzOCe8DClENDOjs/A7G3w5o//KwT1qN6NKRXXOeghHI8jsv0+IFpXVQXhyKyAq56S31dRp9NesD8xBwnVu7iB6WpkoD2WL+jXPsikLCkrF5HwT9nNbGwBUEhLtqMQlAuJfWZKP6t7Y/doLWSrfRIK7vgloPwsf2tRuPCczDADSm0MTzYLljbKKIPf7688iSh/yHIHYwmq8Ai/pu/kIUv0TSHMOY6P0fo5sumcTw1ulTqfdieSO/SoJDjuR59gdCO5ovm/VCi3ggPnu5EjL9o2YwsDMYMWgvkAycLsV1UK39oJXEhV8kfB2WiuK5mooMMGCmZhmtpqG99F0kgux44LFv4d3w56kWv7GGCMrRjKqhep7I/BTTd/xOGb8wnJLwvJxxDjn23cRHBBdguGr3zaCO9Kb72PcS8rcinTGalHVQ/+2hawirHQciutGqLMx9QdPPB0w8zbIEQUDDYj3tI3Om5G8ovGdnDsJIR+Hg60iOrFZkMbPkCgx3cH0TAEWhOMzUXiQWTEP3S1IdVUCHaBNQaSblTVh88fOR92lVutTP9t6A8gMxW1HspTWCKTtKflR1gSJ26DTiJf7UAzvLrMjwNe3yYwobopISxG+NSzHJcApBF4rSA4kqW/gIVc0jlHZv3aN6np/BDpfmQsys0nw8sYwZLOVpb3QhNfQZ3fxjuF7lXrid07uX0hZduyF3haRp8ZMFwtohnQ8+hjugc5SZPDQr3AJAMXnei05rbeKd9zAQ8zZ0JfUSYx3I1Ox5OMhqLZshmNLja8XBoRwrgkkkpodmz/aY10nTFhaeZHcuC4EkVBcKkva SqEqElSd 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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 Tue, Sep 22, 2026 at 04:22:51AM -1000, Chris Li wrote: > On Sat, Sep 19, 2026 at 9:20 PM Baoquan He wrote: > > - Charging: Record the owner at allocation but do not charge. Take the > > charge when the entry gets a physical backend slot, and give it back > > with that slot.memory.swap.current then counts only real on-disk swap > > usage, and a cgroup with memory.swap.max at 0 can still swap out through > > zswap. > > I want the old swap charging behavior back. Please don't change that > behavior. That behavior change should be a separate discussion and > split out from this series. BTW, I am against that change. Charging the swap counter is a hard NAK from the cgroup side. The reasons have been spelled out over and over. Feel free to engage with those. But what you're doing here is not productive or in good faith.