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b=eos85lOv5ieVGVViyeV9H30S6rhaZ66FfCRd2srlJqSdzBHLl0WBvPWL6r9yOs2r5 To3G6fQX1vq9l0WTRVqnxL+X42bA83wlV//sl5G8/n062fFsAAJj15qh0o6LIKNqNp DqtVbDWrg+DY7LZ7QB2TUPxy0mCX53IvR5t63iatip4XaImexBLFdZ3wO2TaK91Knr 5feVfe+iwBC6EydkqVk4Oi8hen+UcAJvn7tR3QYmlxB/XWGVW7o3u4tjySeuUa8T3o 37a5hRNfOrNChzlIhnRdzJoW6x7UHrHjXFuoh0cwDnPZqUSyqkF8yAKcD8/iYhrUa4 aTk5qMMxPuo0A== Message-ID: <51c35e9f-fda6-4a24-acf5-8a332dd505d8@kernel.org> Date: Fri, 10 Apr 2026 11:06:23 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/2] ksm: Optimize rmap_walk_ksm by passing a suitable address range To: xu.xin16@zte.com.cn Cc: shr@devkernel.io, ljs@kernel.org, hughd@google.com, akpm@linux-foundation.org, chengming.zhou@linux.dev, wang.yaxin@zte.com.cn, michel@lespinasse.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260410160600883wV0ynx9z59eSt4_lOUFfK@zte.com.cn> 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: <20260410160600883wV0ynx9z59eSt4_lOUFfK@zte.com.cn> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 7036916000A X-Stat-Signature: oey8w6gc564dfrsfwdxj7xr5kh45sc1i X-Rspam-User: X-HE-Tag: 1775811989-760215 X-HE-Meta: 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 XcFOYEHF wNk1uME9Z1fywSBx4coc2RDZBYsiiu8j3BB9dHE+d7gT8x/NsUyyr6VB64P6OgAHbPh7nIb5cQqRSBdzfm0Gmu0juD4rEh5ulT3nkuULQU2e2Vy3TIuYTDmWUZxveOREydbtL460y30mrRMUVBUycR2kxgZi5dGQNOXArMfnHzdv4mip89WfYyRmbYVdV9lZDyDbJceoaVMHqWZ0HoO59+hN9g97YY8yuJW3ihBcBkQD0jqBZMK0te9u6tTMS3s+aMrWoOBn6AlXQznY= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > It looks confusing indeed, but it does break_cow because when merging two pages into > one KSM, the first one succeeds but the second one fails, so it's necessary to > restore the state of the first successful rmap_item. > >> So we might want to reset the pgoff there as well, OR only store >> the pgoff in stable_tree_append() where we actually set STABLE_FLAG. >> > > Yes, I agree. Please allow me to reorganize all the key points we've discussed, and > update and optimize the patch along with the test program. Sure, let me know if I can help. > > I will try to release v4 for review as soon as possible Yes, no rush. Merge window is about to open, so we have 2/3 weeks where nothing new will get merged either way. -- Cheers, David