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Thu, 12 Feb 2026 10:55:03 -0800 (PST) Date: Thu, 12 Feb 2026 10:55:03 -0800 (PST) From: "Christoph Lameter (Ampere)" To: Ryan Roberts cc: Yang Shi , lsf-pc@lists.linux-foundation.org, Linux MM , dennis@kernel.org, Tejun Heo , urezki@gmail.com, Catalin Marinas , Will Deacon , Yang Shi Subject: Re: [LSF/MM/BPF TOPIC] Improve this_cpu_ops performance for ARM64 (and potentially other architectures) In-Reply-To: <5a648f49-97b1-4195-a825-47f3261225eb@arm.com> Message-ID: <32969518-9106-363f-8a89-479b8246e4b1@gentwo.org> References: <5a648f49-97b1-4195-a825-47f3261225eb@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Queue-Id: 29EE410000B X-Stat-Signature: xafayi866nrqtk8n9opf4jch117sg5y7 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1770922504-936730 X-HE-Meta: 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 g6G9+0Jg KpOd6/OMPTk1+g9EmCyCmWpX9zqeqjaA6dJd56OGpVbho8HLN3B0Y0oTXRQ7v9Wod7I8Iv2MsETRaUtrsbxpSuJHEkR3RawjUJZl+oPCgc4iZf4AsDPWRE62tPG04949nf9oA0SgqCtiZwfEg42l4SQT7krwHgUtIlNyIr4z87i+h4Xq+4MlorU04CRpVjso5LdJi+1wcPGjJsnnafzwVss6dlPyT6Bc2nWvegsaxtcUur/G+6p8rhUbPkc5ZIuYbGhhr/BfG3sOlv8S0H0y/UCAo5MbEfJGKgoJBqRNy6dItd1vhDTRCXoq8bH49tEmu/sC6 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 Thu, 12 Feb 2026, Ryan Roberts wrote: > This is an interesting idea. I'm keen to be involved in discussions. Note also that the percpu kernel page tables that are used in this proposal will also enable additional performance optimizations in the future - Kernel text / readonly / readmostly replication for NUMA configurations to limit the volume of cacheline transfers across an interconnect. - Per node memory allocator to optimize access paths and RMV operations for data that is NUMA node specific. We think that these optimizations are especially relevant for high core count and high NUMA setups. These may be inefficient right now. With these additional scaling improvements more distributed SOC designs become possible.