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[2003:d8:2f4e:3200:c99d:a38b:3f3a:d4b3]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-475c4281314sm59307375e9.4.2025.10.22.13.29.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Oct 2025 13:29:38 -0700 (PDT) Message-ID: Date: Wed, 22 Oct 2025 22:29:37 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [Patch v3 4/4] mm/huge_memory: optimize old_order derivation during folio splitting To: Wei Yang , akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev Cc: linux-mm@kvack.org, wang lian References: <20251021212142.25766-1-richard.weiyang@gmail.com> <20251021212142.25766-5-richard.weiyang@gmail.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+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: <20251021212142.25766-5-richard.weiyang@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: Xin8m01bmPDvRKki7gY0R2hNHKS7BO6Rr2woI3IOMdY_1761164979 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: 47236A0016 X-Rspamd-Server: rspam02 X-Stat-Signature: gr841n4baa4d65ke4wuo1wg7i8gzjdrq X-HE-Tag: 1761164982-490631 X-HE-Meta: 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 heVjdiXw UeDJDgNKy03WpxKDxMFoRXGNlG5s3Eug7vAbxzoj9ACvElxkB4CgIFdS7OmmGSX7RMvtfl0JTZdPn8BzDFJeudUi8b8WRyOrKceX+ugKlVNFPUX/wqzXkG+ixD89KLfT3NQMcY9WC20x5fNlAOn9Q90yYBMZr/ZN2tJSjcy2N2Rz5e5iztjaU7FKEcF6sG9lU7+kLPli8QTvx4rwHpJCQcVxejkkAZmWEwY8ZSvKq7oCcKSbK69lWRRs630oAE1+wAQKib31c5J8Sg7YUKJ5896ajaqtna+mm0CBZ 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 21.10.25 23:21, Wei Yang wrote: > Folio splitting requires both the folio's original order (@old_order) > and the new target order (@split_order). > > In the current implementation, @old_order is repeatedly retrieved using > folio_order(). > > However, for every iteration after the first, the folio being split is > the result of the previous split, meaning its order is already known to > be equal to the previous iteration's @split_order. > > This commit optimizes the logic: > > * Instead of calling folio_order(), we now set @old_order directly to > the value of @split_order from the previous iteration. > > This change avoids unnecessary function calls and simplifies the loop > setup. > > Also it removes a check for non-existent case, since for uniform > splitting we only do split when @split_order == @new_order. > > Signed-off-by: Wei Yang > Cc: Zi Yan > Cc: wang lian > --- Acked-by: David Hildenbrand -- Cheers David / dhildenb