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b=jLPqgKVfOPVsDgLwoMZ16UseK8OHOo8JpJwNW/YVi0kw3fyQlEsd/UVg32FMZs3OW r4P5KEJCPIj/KOyDQJDreVJVPyrB9ZKlgbeWThq5yAcHYydcr3eWO39CsPMsWs4YzX ty8ec6TIzned9CARBFQmSPik48yQoBZn5DuK+GyZh73+m/oGiaCpMUsswuEpUy1+/B 23Ww8KgzPaUGxYKedH2WJ6EK08iuAw/pGCySpsh73GwcFgXbpCs1fGhaD+DjqHzW4p yCNW05kom5Kf5o1qvD3E9oL7GPtzdiHaTHg/5xmtSzKc2wlh09rM45Nyjj1+dO0iMI u+HyATTnHHaaA== Date: Tue, 27 Oct 2026 08:17:11 -1000 Message-ID: <769e80ffa618327ac03c13c4657e7229@kernel.org> From: Tejun Heo To: Hui Zhu Cc: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Kumar Kartikeya Dwivedi , Song Liu , Yonghong Song , Jiri Olsa , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , JP Kobryn , Andrew Morton , Shuah Khan , davem@davemloft.net, Jakub Kicinski , Jesper Dangaard Brouer , Stanislav Fomichev , KP Singh , Tao Chen , Mykyta Yatsenko , Leon Hwang , Anton Protopopov , Amery Hung , Tobias Klauser , Eyal Birger , Rong Tao , Hao Luo , Peter Zijlstra , Miguel Ojeda , Nathan Chancellor , Kees Cook , Jeff Xu , mkoutny@suse.com, Jan Hendrik Farr , Christian Brauner , Randy Dunlap , Brian Gerst , Masahiro Yamada , Willem de Bruijn , Jason Xing , Paul Chaignon , Lance Yang , Jiayuan Chen , Emil Tsalapatis , Ihor Solodrai , Barry Song , Geliang Tang , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kselftest@vger.kernel.org, Hui Zhu Subject: Re: [RFC PATCH 0/2] memcg_ext: dynamic memory.low and memory.min protection In-Reply-To: References: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 558E8140002 X-Stat-Signature: er4kcsdoqxuco3eojaekmf1zwd1xqfnq X-Rspam-User: X-Spam-Status: No, score=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-HE-Tag: 1793125033-670731 X-HE-Meta: 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 qPKDfYFa EYb2tf7hSu0YDLNup4fcZAj+pQ664FheeahkJ9oNSETCrwVzCo/nw6JPi/68mRFi3IwNEeYZsF+pztARMvVIHXC54p9/2AeLUCJKQt8fl6LqgQXEYYjGMRbAVl7rPXcKRZuRVorinAkbbUzxYiiwmrrKQfZFKyd1byGRkY+tf8PzTRvPP/3ovXOJDQSI/HC+aqI2bkzcas/aowwFC1cpqq4sgxqWuoisEky+LnRVKqUbkzXcvInfbLGGZiVsNxq0oGDK4PeVVXA6aTc+6M4k7rzfotxwPo0BknEHl7VfwQ96F0FJcE+CVsbzdn80Ky1F0vP2OAtiMJWZ3nVQKZC9u98lywReXkgVFPgJpBgROsBpJtr4= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: Hello, Hui. On Tue, Oct 27, 2026 at 05:11:58PM +0800, Hui Zhu wrote: > Why it matters: memory.low and memory.min protect a cgroup by a fixed > threshold and have no idea whether it is using the memory. A > high-priority cgroup that holds a large working set and then goes idle > keeps suppressing reclaim on its siblings, and that memory is wasted. > A policy program sees the real activity - page faults, charges - and > can grant or withdraw protection as it changes. This doesn't justify the changes. Why can't the same be achieved by adjusting memory.low and memory.min from userspace? The arguments made so far are neither convincing nor proven. Thanks. -- tejun