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Perez de Azpillaga" References: <606cae9e.bbec5.1a1c54f4f9f.Coremail.18670333770@163.com> <60541e98-b1f0-4f92-a155-8a29c0bb17dc@kernel.org> <44abb8ef-7711-4ad0-be9f-ca47206892a3@columbia.edu> <856cdf21-7982-475a-b244-a7ceff4eb6aa@kernel.org> <71e24630-4c71-4518-a9b7-68cf3597ce80@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam09 X-Stat-Signature: edaonoa8edjkk7apj8hu8fat9m39az83 X-Rspamd-Queue-Id: 60151C000C X-Rspam-User: X-HE-Tag: 1794432944-212630 X-HE-Meta: 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 WVFM/eQf Un0yP1HckQkErWOMpdaNIthiP73YcKLExRQt5h/yCrtPzCGkzpMYKCijsuSTEWgrTS+ZprQIsb4NjE3qMO7V1SG7QLiLLJkdtP2VYL/D5IoJWEIdFBkKATnpiMsqvalV/XCX2tQDOrj1B13Gw4/SAXx7d5C2+hl1VdyRVXSq+lFv/5YIWa5vnNxPaanBvI9BWhJ4lg774FWpuHOvbP1ShdVJMDp08a187Hv0NLxe0tQzN+CsOOTTcNvtyZDBDBuHj9l21o89cj+dlz88oDeqyPUNABJQ7Dff4HUWwBeA01YdTsVasjoB/NQn93eFDtXjvtarUdfznAjWlQiUs0GyPUtoMPqiYLNsG/BNI1wff06ZJEoFlKFl/WIqW+Q== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 11/11/26 21:55, Linus Torvalds wrote: > On Wed, 11 Nov 2026 at 12:20, David Hildenbrand (Arm) wrote: >> >> It would be a lot more consistent if we'd just add marker support. Or is there a >> good reason why that is explicitly not wanted? > > Let's not help people do things that won't work on older kernels for > no real gain. Uffd folks usually indicate such things through new uffd features. > > Is there an actual real-life user that would care and be enormously > helped by such a thing and it would increase performance or something? > That sounds very unlikely, since presumably re-faulting never happens > in practice, so just tracking it in user space is "free". > > In the absence of some real load with a real argument for it, please > let's just document existing behavior to the fact that you need to > simply see the re-faulting of these things.. Just to express why I would even dare proposing to implement something in userfaultfd: in Kiryl's series we abstracted the uffd-wp PTE bit to a uffd PTE bit, which made things more generic. Abstracting uffd-wp markers to uffd markers would similarly make things more generic. A quick codex prompt tells me: 90 insertions, 95 deletions. But most changes are documentation either way, so that doesn't reflect reality. Now let's ignore what I wrote above, I just polished another uffd fix and most fixes I looked at throughout the last days were uffd related, which is starting to get annoying. So yes, no new uffd features. -- Cheers, David