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Sat, 14 Nov 2026 11:57:01 -0800 (PST) Received: from [172.22.0.2] ([4.16.0.251]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3b197ce460csm14709280a91.5.2026.11.14.11.56.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 14 Nov 2026 11:57:00 -0800 (PST) Date: Sat, 14 Nov 2026 11:56:57 -0800 From: Chris Down To: "Lorenzo Stoakes (ARM)" Cc: David Hildenbrand , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , David Rientjes , Shakeel Butt , Andrew Morton , Jann Horn , Pedro Falcato , "Matthew Wilcox (Oracle)" , Jan Kara , Nhat Pham , Johannes Weiner , Zi Yan , Matthew Brost , Joshua Hahn , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Usama Arif , Kairui Song , Balbir Singh , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Kiryl Shutsemau , Yu-cheng Yu , Dave Hansen , Dennis Zhou , Tejun Heo , Christoph Lameter , Peng Fan , Josef Bacik , Chris Mason , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, "Borislav Petkov (AMD)" , Mark Brown , "Dennis Zhou (Facebook)" , Rick Edgecombe , stable@vger.kernel.org Subject: Re: [PATCH v2 08/13] mm/migrate_device: fix ksmd oops on a migrated KSM page In-Reply-To: <20261113-mason-migrate-et-al-fixes-v2-8-50a2ed382b61@kernel.org> References: <20261113-mason-migrate-et-al-fixes-v2-0-50a2ed382b61@kernel.org> <20261113-mason-migrate-et-al-fixes-v2-8-50a2ed382b61@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Message-ID: <20261114115657.f63de4714929f7af@chrisdown.name> User-Agent: Mutt/2.4.3 (cc9e3943) (2026-10-09) Hi Lorenzo, Lorenzo Stoakes (ARM) writes: >[ ljs: tweak commit message, comment, also refuse device coherent ] Alistair's Reviewed-by on v1 came with the argument that KSM pages should still be able to go to device coherent memory [1], which is the opposite of what this does now, so it's probably worth checking that he's happy for it to be carried over. Going by what ksmd does with zone device pages, the change itself looks right to me. I've tested the device private case. Without this the process hangs the next time it touches one of the pages, and with it the migration is refused and the pages stay merged. [1] https://lore.kernel.org/r/avTu3LmscsttRVRp@nvdebian.thelocal Reviewed-by: Chris Down Tested-by: Chris Down Chris