From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C6BE8C54F54 for ; Tue, 28 Jul 2026 19:01:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 32B256B007B; Tue, 28 Jul 2026 15:01:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2DE846B0096; Tue, 28 Jul 2026 15:01:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1CCCE6B0098; Tue, 28 Jul 2026 15:01:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id D83706B007B for ; Tue, 28 Jul 2026 15:01:24 -0400 (EDT) Received: from smtpin15.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 41EDFC045B for ; Tue, 28 Jul 2026 19:01:24 +0000 (UTC) X-FDA: 85039103688.15.BD21EE6 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf25.hostedemail.com (Postfix) with ESMTP id 703D1A000F for ; Tue, 28 Jul 2026 19:01:22 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=oepwlxHn; spf=pass (imf25.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1785265282; b=6PXi0/nLDcxWmx1DxRBR7aGOlh4jmNQOVaULgmr9miX+wZNDPXQWW3z2IHBBNoQGcU+3u3 VDWUwlTKL/jqZ0UVnre5bKbksdq6wejY2vy6WRDrqGhgAsjrQSotjwKzHyRAr22YUwdXG2 eJUo8nCMwLCer6VBUWm2F/8888ui640= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=oepwlxHn; spf=pass (imf25.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1785265282; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=AV1Nv4qp1K5kHtg080G8H45YsblDUrxFOLCmgn7R6zw=; b=woJcG1jodqLh7aKi5H0e3UN4XttMV83zyDdxoYHBOSBYrAr6W2MAi35E/p9mkfEKI8fEMQ G1ee0uxs3s+Pdr8scuruhPAGY/Xkla9zVUp6Hzd24Xda+8n1Km3CXEvpGCE+5d/h7gZEgn fSlIIDrhUKtlDmrddahX83oI8XARbgA= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 7014440B08; Tue, 28 Jul 2026 19:01:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5CF691F000E9; Tue, 28 Jul 2026 19:01:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785265281; bh=AV1Nv4qp1K5kHtg080G8H45YsblDUrxFOLCmgn7R6zw=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=oepwlxHnOmRfh3pX0SUHSbK77m5qX2t05E5d6/5NRfOZFwI7PjGCnbFH30HSefbvi NBkI+RAd46u7ZHVfo1oQDIh2dYXAtKVINfjbv8DxiYmEShio/oe2JVwWaSAFlC99Wc C2b9iS9EOAqzRoI8Tkb4Ty6Nj2yg4F43TqO0IyMd6eS8ZKuhbrwqtqvT0UtG06qEqb lgmjvBkcVSbfV/8Jjk7+RZ558nwRPNpDlgwsq/glTqM56awXHyLd1hS8ZlKAJMrCHc VxUJHW7ENXx9fNFAYGmRYYwbrm8HHS0YXgFW+w9ORsjx4ScL5526eEvm+6tbatAQCl dkfYhki3qLnmg== Message-ID: Date: Tue, 28 Jul 2026 21:01:10 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/3] mm/huge_memory: add folio_split_driver_managed() To: Zi Yan , "Lorenzo Stoakes (ARM)" , Matthew Brost Cc: intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Christian Koenig , Huang Rui , Matthew Auld , Andrew Morton , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Tvrtko Ursulin , Dave Airlie , Matthew Wilcox References: <20260722044220.1110278-1-matthew.brost@intel.com> <2FD2B991-09B3-40EE-8230-49BE3A239EEC@nvidia.com> <603ef1ec-bccc-4fe4-9523-e8b8a731be63@kernel.org> <00499B8B-F546-4A4E-84A6-126BAE5BC239@nvidia.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: <00499B8B-F546-4A4E-84A6-126BAE5BC239@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 6uca9ikfr5yiq4s5jgmp9gcnwsw3u6a9 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 703D1A000F X-Rspam-User: X-HE-Tag: 1785265282-268884 X-HE-Meta: U2FsdGVkX18EMNVShJkPSQKWeDAkaoN5fozNH26JZTatVff7ZKTZkSfQI9ROiSYYXJFAk8os866FRnVFblMEJNRmbRr9KVu162rhW2m62tMrGyat5T6aA9Hx0bF7H0ZrDwWzTJlfKbL48MCAmEeHTr9m3HkYDUosh37yCVdi7hSbmbPQzMjytuKA68RO23772657Zg5JyN2MAJnHWicPCCBOwldhzY3zTvqP18o5PogXerT8dHVTMpG0Rr4vhtFNjguYmtozAfPJLSVL+8yC+XQ109HHp3RIwtztUDDSZeLfpYxB/akdMRyHUkMXJbE9sgW9f1NsHDFY9T+bYbimwulE1HbN68sjcWLRMvcTLAIy+kEjO36Jclmn3DaPVthm5NEuM2UC4LMXppo4HOJHxywHh24KS67vOqEJcZgDya5TbuZVLEvxEJ0ji1G4ubwCgq2E+SbO9pv7kWkybFSHQv7m8nMn52vWD2FJudJS1vXC4pz6Dn5gHurKbJmHDzRMFD4bFpoBMevCt5hfh4uogOCFdd5HVknOxDoThkDyRWc5GSTY3gaVeNyxSpcsGPYU1IGORvgyv3V62QMxFTuS5pjZlbcaDuC4LgV7C0/aMcYp3vf8FaZ8nIud0iv8BB5bwcxnr/JAe/A1uLbqoTeTsOlUVDrrGqlE0dxZQr6gEPs2nUiB0vksGJXpptfbQ+bkipUCh4juGJ2d3SmO5rIGqEGuq53t7L6FRCl1Qa52puIAlN9Xy219wRd8Q3deQtVej0szuA1yh6362y7LzI3WT//9qthEIQ6POpn+l0/MRgMHjszGcSQJqkKbeE0dfStGHNbnRnoH1EC1on0biN3MmAYLmyxDTtZhwGNGsVEBn4aEyQueUht/zIulHM5jov3bAyuAfV1xzETgMeZBb6ZrTwJU/1RR6cH7Zc+H9T1QhQARlt9bOHk9RxwZelrpxchVLK12Fe67Ab4wsIUF2S2 I/eIGD5d IPd/KDKu9X4eoqP1OzcHRVSYWfI8l8/J5qfOAO+iVqXda6KlklTMrpqa78VzO8ecohGZhbO/3AW6JjUD3VYE45NoJb2jXza7xrmnvgQod9n+gHwivOwFatiJKu8ujVQstuAEvUnBgFB/cZWW7k9H6ub7xR8rytZug57qk+llr6RyuvJQ4xXJ//dZ3lkoQ5tof+24rh8cKbnP2Rrpi/lHjCVYU+FfLdrP9OvwoJZS2QVGoX3vme9Wc+QmKjp5G75RqBG2EYtKu5GOP4PyZik0dfCyEOc5Oh2Uwot/NOlDGjhZLuCiATkfMAdUWneUE4P0DHR4+oujZ7Jb6mDU= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: >>> Because splitting a folio is really something different than splitting just some >>> compound page (no mapping/pagecache/whatever involved). >> >> Yup. > > It sounds like split_compound_page() gets some love (David, Lorenzo, and Matthew > all want it). I can add one to mm/page_alloc.c, so that Matthew can build > his patchset on top of it. In there we should verify that it is neither slab nor a folio. For now, we can only test for folios indirectly by considering the large_rmappable flag and hugetlb page type. Likely we should simply disallow any page type for now (and large_rmappable). -- Cheers, David