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Thu, 18 Jun 2026 19:56:01 -0700 (PDT) From: Xueyuan Chen To: david@kernel.org Cc: xueyuan.chen21@gmail.com, dave.hansen@intel.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org, catalin.marinas@arm.com, will@kernel.org, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, hpa@zytor.com, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, yang@os.amperecomputing.com, jannh@google.com Subject: Re: [RFC PATCH v2 1/3] mm/huge_memory: make persistent huge zero folio read-only Date: Fri, 19 Jun 2026 10:55:53 +0800 Message-ID: <20260619025553.226940-1-xueyuan.chen21@gmail.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <0e5b23a6-4895-454a-9dfa-6dc21adc2991@kernel.org> References: <0e5b23a6-4895-454a-9dfa-6dc21adc2991@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On Thu, Jun 18, 2026 at 02:36:25PM +0200, David Hildenbrand (Arm) wrote: Hi, David [...] >Best to wait for some feedback. Sure. >I do wonder whether we want to pass an address instead of a page. > >https://lore.kernel.org/r/20260410151746.61150-2-kalyazin@amazon.com > >Wants to convert existing ones as well. > >That would imply that the caller must check for highmem. > >But then, we could just use existing set_memory_ro(), right? > Agreed. Passing an address and reusing the existing set_memory_ro() definitely makes things simpler. However, there is an arm64 specific limitation: currently, the set_memory_r* api on arm64 only support the vmap region and do not handle linear map addresses. If we go this route, should I extend the arm64 set_memory_r* implementation in the next version? The plan would be to make it check for the bblm2 feature and modify the linear map PTEs accordingly. What do you think? Thanks, Xueyuan