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[96.255.20.138]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-5070d54000fsm71259831cf.10.2026.02.23.08.08.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 23 Feb 2026 08:08:40 -0800 (PST) Date: Mon, 23 Feb 2026 11:08:38 -0500 From: Gregory Price To: "David Hildenbrand (Arm)" Cc: linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, damon@lists.linux.dev, kernel-team@meta.com, gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org, dave@stgolabs.net, jonathan.cameron@huawei.com, dave.jiang@intel.com, alison.schofield@intel.com, vishal.l.verma@intel.com, ira.weiny@intel.com, dan.j.williams@intel.com, longman@redhat.com, akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, osalvador@suse.de, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com, apopple@nvidia.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, yury.norov@gmail.com, linux@rasmusvillemoes.dk, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com, jackmanb@google.com, sj@kernel.org, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, muchun.song@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, jannh@google.com, linmiaohe@huawei.com, nao.horiguchi@gmail.com, pfalcato@suse.de, rientjes@google.com, shakeel.butt@linux.dev, riel@surriel.com, harry.yoo@oracle.com, cl@gentwo.org, roman.gushchin@linux.dev, chrisl@kernel.org, kasong@tencent.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, zhengqi.arch@bytedance.com, terry.bowman@amd.com Subject: Re: [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) Message-ID: References: <20260222084842.1824063-1-gourry@gourry.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam09 X-Stat-Signature: iz1b63886kuk39u65xmp5ty1fj6aud3j X-Rspamd-Queue-Id: D15AB40003 X-Rspam-User: X-HE-Tag: 1771862922-193910 X-HE-Meta: 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 AuY7t9Df RxyMVRBT92Lp9EUMFcgxYUGRIx1dMMNP5tEAB1kIDUDjwgHZLmJs05WRlxcyquVIRz1rPL04C6IkmLWH501ZPQvsWHN40csN1A3tKxY5e+oSvWmBN6+d0btoP8CzcWIKkKZfWHfr9Ilr0a/XRt+lGI8jv5/IWwkO1JRgCgZ6je87NYU6uusU4Mcb2tkMROC0nzHJhfqFRrDDfp9pjjwUhzhIp/NABwablFRC9uplAXs1ZAfHW0M0QANvEroRYvjRDyYKL4hfsPf+cmVukMMuQgDz6Gl+istbXxrWRh+E9xNiVFKU7JikxXPQnEgEzs6o8ahpaz4z9oEpYGOWe+KriIKpaaW8GlA3IdTx3Lh2lKYZWHlwL+4jQHFW3LUMvxluE5D/AefkSY0zIhS4rPzk4ThzKpA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Feb 23, 2026 at 09:54:55AM -0500, Gregory Price wrote: > On Mon, Feb 23, 2026 at 02:07:15PM +0100, David Hildenbrand (Arm) wrote: > > > > I'm concerned about adding more special-casing (similar to what we already > > added for ZONE_DEVICE) all over the place. > > > > Like the whole folio_managed_() stuff in mprotect.c > > > > Having that said, sounds like a reasonable topic to discuss. > > > > Another option would be to add the hook to vma_wants_writenotify() > instead of the page table code - and mask MM_CP_TRY_CHANGE_WRITABLE. > scratch all this - existing hooks exist for exactly this purpose: can_change_[pte|pmd]_writable() Surprised I missed this. I can clean this up to remove it from the page table walks. Still valid to question whether we want this, but at least the hook lives with other write-protect hooks now. ~Gregory