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b=freCKJAL/5srsOPPHnZ1/GheZ0Tp9YRXahDWdvn3iGHCEVxv5gpEWtcN5AZeT/nXM W6y9p0tMtNiejtHHEP0cZdNjlIj6byDv8RC/sLXE/gbAPVUW78HgVlhKPq7jMxFm5j 5BwBx5sUTnAk6DivwvHKl552uXE8VSJd5Iw/Youfeq+bG7N5x2FxacGqUU+Hv+/Ab9 31LfL2Tywjais5WFKJpGDPN3k6bwZghOFj6k9urCxW8wFmEZLqd3nh04zMDyHNG+P8 qSzNmLFVyDDorL8kSlizEDLy9KP45J9tJoRcb3nGmp3orKXLB70QYu32ikw3XAsvbF f3Y28yYKvvEPQ== Message-ID: <835725cc-1670-45ae-bf58-593aadec6b88@kernel.org> Date: Thu, 2 Apr 2026 10:25:13 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 00/11] mm: thp: always enable mTHP support To: Luiz Capitulino , linux-kernel@vger.kernel.org, linux-mm@kvack.org, baolin.wang@linux.alibaba.com Cc: ryan.roberts@arm.com, akpm@linux-foundation.org, lorenzo.stoakes@oracle.com References: 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-Rspamd-Queue-Id: 1881D12000F X-Stat-Signature: ymx589587ihnfu37ncsf7gm5z4tu4am1 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1775118318-752784 X-HE-Meta: U2FsdGVkX1/TKkmq1XizEDiwZGEfciIRO2HB0Q4VCjobgOJyIxYlTHIlIJSAmJ1qXBv2BnOE/Dhbta/8V7MT3xRn1nGM1v/I6YtbrJpUPccFvoYDIywhADH0pt1wqPNQiuWaJDq33yhg5dwJQ3l8SdP5PYdTjEDe/qS/B6WNJBWw0rBA2kIkjdh6M/aNNJvuQN/JsMOKlNtzE0+pc8RsvKJbf4j4BTU913ADcGafRkieGkClU5PeoFjX13qlcXIaakKu855gSA7Qte2Oj8zp6NkCNWbDxaGwjlaKABg/EWLqTwgAwV9BqlLN3Bi4fWtzfcxvwOnK2XAFqjaxDcivUle3AM7B/Q/+2ghcSjcBGiEK2M7OqIUeir4gPlUKwRO7Asgl2my1aFtL+w0eF8Ldx050UJc7tozoa9z/FPK1cR5vOeBNDof6xSnYqb50KyVhIr9fkk50vP+2f2KWtybT+oqkYKfqMtvhw5kZHwdrWDogEAF4/bHrYv/CsdnWoBlrhPNwEdPxklqAbBMSl9FPafezYBI91IIwn8e2uqWMOsr7IwblBZBtuLkar8SefHAY03V8exccnZo6aU3awAv9uqSSeyxYxnLtCZ3eDcimzAjdCvGkhNE02K9BVRvxuLlmo9jsMZ3wjOY7EeBpSJGN6PemO9spMu+w7CoS8b5tKRV9lrPuvRuptcAUWXpaSzKyFIt1ze49YWJ/rVrsWIcgSako01Nd+duImKqQS5A34bssbpaw3TB9ELxuJaZU1izPOuKnUYfUrZLAvvdvdRvfPv6U8PCJEC008uNE9ic12Nabp4yGjpJ0P80xWsJht6Xrrx/Re1OgZTLneA7d8CM3j1rrSMBlUBSa97ShSpGaxYaiS6iX+6uMUr8LOOmFpeTZFieb/EvLhkn6StBBqosEgXcDu7kyg7KxLozYUNyj2PLt85fqhkDGveT6fDuAqYysvdl6WgdHIVt5QPdp3JU 1EGabiVv SdKllmjqmswVDuR+b653OYJN0ur8YD3vFX4ow8qdgO+1r0bq6Wi8cXNjUp+a/YTe3it86srCLlDiDxBCtLkntT1FoH3P1hmtGMT6Ct1Trc9Gs/GHIkNpMLSUuzRHJx1hIyutZcPMi95Z4oPNqvkPqLRsUnv0v0aXHiE9YoUKCtNHqUMHLZEKURBMu7o9U9taanlKoysBa+rT+aXBr/9iW15Nt/wzip0xnluOA Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2/9/26 23:14, Luiz Capitulino wrote: > Today, if an architecture implements has_transparent_hugepage() and the CPU > lacks support for PMD-sized pages, the THP code disables all THP, including > mTHP. In addition, the kernel lacks a well defined API to check for > PMD-sized page support. It currently relies on has_transparent_hugepage() > and thp_disabled_by_hw(), but they are not well defined and are tied to > THP support. > > This series addresses both issues by introducing a new well defined API > to query PMD-sized page support: pgtable_has_pmd_leaves(). Using this > new helper, we ensure that mTHP remains enabled even when the > architecture or CPU doesn't support PMD-sized pages. > > Thanks to David Hildenbrand for suggesting this improvement and for > providing guidance (all bugs and misconceptions are mine). > > This applies to v6.19, but I tested it on v6.19-rc8+. Apologies for the delay Luiz (as told you off-list :) ), I'll try going through this soon so we can start queuing this after -rc1. -- Cheers, David