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(p200300d82f28de001efe3ea463ba1713.dip0.t-ipconnect.de. [2003:d8:2f28:de00:1efe:3ea4:63ba:1713]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4562e803cb3sm181199025e9.14.2025.07.22.00.59.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Jul 2025 00:59:11 -0700 (PDT) Message-ID: <64b5b420-4c2a-423e-825b-b2c309274d71@redhat.com> Date: Tue, 22 Jul 2025 09:59:09 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] docs: update THP documentation to clarify sysfs "never" setting From: David Hildenbrand To: Lorenzo Stoakes , Andrew Morton Cc: Zi Yan , Baolin Wang , "Liam R . Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Jonathan Corbet , linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250721155530.75944-1-lorenzo.stoakes@oracle.com> <39a75435-5fea-4816-b484-477d400c3564@redhat.com> 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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAmgsLPQFCRvGjuMACgkQTd4Q 9wD/g1o0bxAAqYC7gTyGj5rZwvy1VesF6YoQncH0yI79lvXUYOX+Nngko4v4dTlOQvrd/vhb 02e9FtpA1CxgwdgIPFKIuXvdSyXAp0xXuIuRPQYbgNriQFkaBlHe9mSf8O09J3SCVa/5ezKM OLW/OONSV/Fr2VI1wxAYj3/Rb+U6rpzqIQ3Uh/5Rjmla6pTl7Z9/o1zKlVOX1SxVGSrlXhqt kwdbjdj/csSzoAbUF/duDuhyEl11/xStm/lBMzVuf3ZhV5SSgLAflLBo4l6mR5RolpPv5wad GpYS/hm7HsmEA0PBAPNb5DvZQ7vNaX23FlgylSXyv72UVsObHsu6pT4sfoxvJ5nJxvzGi69U s1uryvlAfS6E+D5ULrV35taTwSpcBAh0/RqRbV0mTc57vvAoXofBDcs3Z30IReFS34QSpjvl Hxbe7itHGuuhEVM1qmq2U72ezOQ7MzADbwCtn+yGeISQqeFn9QMAZVAkXsc9Wp0SW/WQKb76 FkSRalBZcc2vXM0VqhFVzTb6iNqYXqVKyuPKwhBunhTt6XnIfhpRgqveCPNIasSX05VQR6/a OBHZX3seTikp7A1z9iZIsdtJxB88dGkpeMj6qJ5RLzUsPUVPodEcz1B5aTEbYK6428H8MeLq NFPwmknOlDzQNC6RND8Ez7YEhzqvw7263MojcmmPcLelYbfOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCaCwtJQUJG8aPFAAKCRBN3hD3AP+DWlDnD/4k2TW+HyOOOePVm23F5HOhNNd7nNv3 Vq2cLcW1DteHUdxMO0X+zqrKDHI5hgnE/E2QH9jyV8mB8l/ndElobciaJcbl1cM43vVzPIWn 01vW62oxUNtEvzLLxGLPTrnMxWdZgxr7ACCWKUnMGE2E8eca0cT2pnIJoQRz242xqe/nYxBB /BAK+dsxHIfcQzl88G83oaO7vb7s/cWMYRKOg+WIgp0MJ8DO2IU5JmUtyJB+V3YzzM4cMic3 bNn8nHjTWw/9+QQ5vg3TXHZ5XMu9mtfw2La3bHJ6AybL0DvEkdGxk6YHqJVEukciLMWDWqQQ RtbBhqcprgUxipNvdn9KwNpGciM+hNtM9kf9gt0fjv79l/FiSw6KbCPX9b636GzgNy0Ev2UV m00EtcpRXXMlEpbP4V947ufWVK2Mz7RFUfU4+ETDd1scMQDHzrXItryHLZWhopPI4Z+ps0rB CQHfSpl+wG4XbJJu1D8/Ww3FsO42TMFrNr2/cmqwuUZ0a0uxrpkNYrsGjkEu7a+9MheyTzcm vyU2knz5/stkTN2LKz5REqOe24oRnypjpAfaoxRYXs+F8wml519InWlwCra49IUSxD1hXPxO WBe5lqcozu9LpNDH/brVSzHCSb7vjNGvvSVESDuoiHK8gNlf0v+epy5WYd7CGAgODPvDShGN g3eXuA== Organization: Red Hat In-Reply-To: <39a75435-5fea-4816-b484-477d400c3564@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 7BkroHvXwrQ_cwcqGrxt5KaLKcJJZTT5WlLM1H89Me8_1753171152 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: 8niacf39rsmjhmgsocpnasmsdho3o7mm X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 70EB7140006 X-Rspam-User: X-HE-Tag: 1753171157-942615 X-HE-Meta: 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 Qesjeqxr egLy1tv20KrMDrUiJvriOAqMD38sgiqP+xCltOu+tNqP4BxpBSVLa1TUWDt4y0NrTI/G5mwuCsuwkHdwV2zNTnVcZBO0PIg8b9NXy0j81MqCQ7YV/iHtE+IfiVvDmKotfytB4WdVSX5lHnUhKuy99A1mY1F909pzR+4m27nbuYH2ku+166qzNlpFAYmWos2hiDn5Ctp2or4YJ7aoZP27mYpGVwDB03QoVwP8tqD8GNc7fnDaetH4TMmSMm0bvHa9FA/LkALAttapxvlSTG+ju9bkC10UWMIzgi5Mt8/5EXGqCxrrFE5AFr2To54B/8fAl0+Ax0jFEyfvt8VfVEq+EKEwl7s5wQqQklsaB69W6dav8gMTbqJQ/z7vqYP3J7kkBrtn9pxpyw2mVSOBevqXcuBUjvAGPBeVKACRBw1/coVuBp3hamJGWxgrnx0Uz5/pDoJUIaWh5E/NQIFFIr/hf7SW4c8Dx5w8jVAjz 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 22.07.25 09:20, David Hildenbrand wrote: > On 21.07.25 17:55, Lorenzo Stoakes wrote: >> Rather confusingly, setting all Transparent Huge Page sysfs settings to >> "never" does not in fact result in THP being globally disabled. >> >> Rather, it results in khugepaged being disabled, but one can still obtain >> THP pages using madvise(..., MADV_COLLAPSE). >> >> This is something that has remained poorly documented for some time, and it >> is likely the received wisdom of most users of THP that never does, in >> fact, mean never. >> >> It is therefore important to highlight, very clearly, that this is not the >> ase. >> >> Signed-off-by: Lorenzo Stoakes >> --- > > Can we also somehow tone down or clarify the "entirely disabled"? Ah, missed that you touched that already. Acked-by: David Hildenbrand -- Cheers, David / dhildenb