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b=OwWWkCfmwSJazt6Bl6SPLtj1PCppUfp38Lf0p9XHHEmjjh+JRHXNZTlPpsgc5ZrT6 HF+hnGowGlh0El7GD1dmDRBlKTxRvoTUeWng9Rq3yL8XQuBOeoIU6iWV+mwHe1Vc1G s6bsMuyDSlGRZgPHPI8oVfsOJm9b60+dLlml5UJlLxfA8cZkXEpj//0bws9rzxFROB Q+kXxxzJWzLIrR9OWXap6yZEKiQqz5V05GJ6xUCl9Ew6kfI3c3h/A/tTZgC6DIxOEk HYaMxGcUDSJXHfSqy7m/5WebBws7TkYXq5NePlRWkGnxGMSTQGUOFGMm3/nR7mJ8ar ROnSXMmw13vqA== Message-ID: Date: Tue, 7 Apr 2026 08:48:22 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] perf/events: Replace READ_ONCE() with standard pgtable accessors To: Anshuman Khandual , linux-mm@kvack.org, Andrew Morton Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260227062744.2215491-1-anshuman.khandual@arm.com> <1267a6c0-f8e7-4708-96da-4d131b5c6069@arm.com> 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: <1267a6c0-f8e7-4708-96da-4d131b5c6069@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: D913840004 X-Stat-Signature: m59exs1m4it61e9pajk8jxbh9jhztqny X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1775544507-548337 X-HE-Meta: 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 tBpeN/nJ 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/7/26 05:28, Anshuman Khandual wrote: > > > On 27/02/26 11:57 AM, Anshuman Khandual wrote: >> Replace raw READ_ONCE() dereferences of pgtable entries with corresponding >> standard page table accessors pxdp_get() in perf_get_pgtable_size(). These >> accessors default to READ_ONCE() on platforms that don't override them. So >> there is no functional change on such platforms. >> >> However arm64 platform is being extended to support 128 bit page tables via >> a new architecture feature i.e FEAT_D128 in which case READ_ONCE() will not >> provide required single copy atomic access for 128 bit page table entries. >> Although pxdp_get() accessors can later be overridden on arm64 platform to >> extend required single copy atomicity support on 128 bit entries. >> >> Cc: Andrew Morton >> Cc: David Hildenbrand >> Cc: Peter Zijlstra >> Cc: Ingo Molnar >> Cc: Arnaldo Carvalho de Melo >> Cc: Namhyung Kim >> Cc: linux-perf-users@vger.kernel.org >> Cc: linux-mm@kvack.org >> Cc: linux-kernel@vger.kernel.org >> Acked-by: Peter Zijlstra (Intel) >> Signed-off-by: Anshuman Khandual >> --- >> This patch applies both on v7.0-rc1 and mm-unstable. >> >> Part of the D128 series but independent. Hence could be considered on its own. >> >> https://lore.kernel.org/all/20260224051153.3150613-5-anshuman.khandual@arm.com/ >> >> Collected Peter's tag from an off list conversation. > > Gentle ping. > > Still don't see this patch in latest next-20260406. Hence just > wondering which tree and branch this patch is being picked up ? It's a trivial change and the last generic code change required for you arm64 D128 change, right? I would assume this to go through the tip tree, but if Peter agrees we could route this (mm) patch through the MM tree. -- Cheers, David