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Tue, 17 Feb 2026 09:28:34 -0800 (PST) Date: Tue, 17 Feb 2026 09:28:34 -0800 (PST) From: "Christoph Lameter (Ampere)" To: Catalin Marinas cc: Yang Shi , Ryan Roberts , lsf-pc@lists.linux-foundation.org, Linux MM , dennis@kernel.org, Tejun Heo , urezki@gmail.com, Will Deacon , Yang Shi Subject: Re: [LSF/MM/BPF TOPIC] Improve this_cpu_ops performance for ARM64 (and potentially other architectures) In-Reply-To: Message-ID: References: <5a648f49-97b1-4195-a825-47f3261225eb@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: E694F160004 X-Stat-Signature: 9q7tauwcqwucx959fr7w4xjuu7jjtcfb X-HE-Tag: 1771349315-490798 X-HE-Meta: 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 d24HhU4P W/L2++xnGQGAqmgQdmHrZhnany4wUyvqbTcqLnWFK8lEh/wXcHg5JYwB4GtzWqcYCjxMDvWtSRc277fvyJCYSwGELD5yks46Y/huW+XiqfT85nv3WwCLI0dvwCy8cXuLFMHZRNQkH3EtIUImwkE6J/xcS152FCy9/QOoA9MVY8qqPCvR+KLqBqhJMxk8p+DfkAS16lxgJc3jTlMb+/P25h3T6i9qGBTYgC3wOamxe3t0VhEDAoQpHM44PJOFJuh/yEPiD/wqozGfnIBvC3mbyOL2gi1G7Q1iAGh0NAJcETxzqLxFxkVz6a5UqDOl2WBOVD39hwYTPcFZWZ6g= 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, 16 Feb 2026, Catalin Marinas wrote: > It's not about TLB conflicts but rather using the wrong translation for > a per-CPU variable with CnP. These conflicts could only come about if each PE would not be able to have its own page table but share page tables between processors. That is not the case from what I can tell. The ARM64 code does not support a shared page table and if I remember right Windows actually requires a per processor page table.