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 B5A6AE98E0F for ; Mon, 23 Feb 2026 09:36:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EF6566B0088; Mon, 23 Feb 2026 04:36:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EA3AE6B0089; Mon, 23 Feb 2026 04:36:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D5B206B008A; Mon, 23 Feb 2026 04:36:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id C35F36B0088 for ; Mon, 23 Feb 2026 04:36:56 -0500 (EST) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 6E73E13BC0F for ; Mon, 23 Feb 2026 09:36:56 +0000 (UTC) X-FDA: 84475217232.20.0BB1BBF Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf14.hostedemail.com (Postfix) with ESMTP id B2ECA100003 for ; Mon, 23 Feb 2026 09:36:54 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="OCS/Oxe+"; spf=pass (imf14.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 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=1771839414; 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=gT5iInjxDhSQB4omwEw633TVDuZHS7fTWQCIfSqEbeE=; b=6OtxSxZyXbPkAvuWS0Cb5g/xwpJwgbRMmRDVAhbZwhFHrkkv7xYCWw6wcP85zz1VAh0il6 sdg6YgGdl1uEn9yrho+RSWSZ87n35ZOoMYUmIm9M87KxLgD4NTGuRmqcYZpyEQuUO7cktk M8h6bZbFr/fldH5/qTZqa2xZcI3QSMs= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1771839414; a=rsa-sha256; cv=none; b=zhSS4KdNrMcXbVrsnAR6/1pX6KPLbh6DjbsUF4ffLPF7IxiegzxHdz8swmPTkgS6tj3l+a xdyzt4t22DxpLzbEt+0n/W1LtaUOhUeq+go4fzrcgnwx1zllbD7wDHLfL6kjyUDMjL4hQb Pa4g/AQva1VgmfTGz7PXkNPmhzcVoi8= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="OCS/Oxe+"; spf=pass (imf14.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id A65D960054; Mon, 23 Feb 2026 09:36:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7BB8EC19424; Mon, 23 Feb 2026 09:36:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771839413; bh=0jMHGP/ybufSz9lSb0ZxZMotoqEwnfv1L084yPjko08=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=OCS/Oxe+Dxgz+x+xdUK/MYBO0KYN9A8SZFhWmTCCYz09A6lLOmm0uN5o6h7jMzG2Q jRFenKp9st0gV3TjgABTQgDrtgQ4hthtQYeoS8BvjHkxFb9TZa+DzTqltblbK0bnZj PTURObvt0rZihgvX4BA4ptBpDGCg21GZiA8k6fRayqylGJCXCLs+FligqQjx4JlxJ8 wtf6nUlUn96LYP8M84pt9Zs2vz1o92hBGuSRYaOBpe7yA9Nxf547jnW90lIsB1uO9R TW30TzjPUMgqMt/5wwjjya/3hUZIk5rkroJnbqCWY1RiILUhVwYeJVt9SE06Rrnl22 BMoG/sCdcY2zA== Message-ID: <492f2fdd-3f1f-4303-b512-ef90b649910a@kernel.org> Date: Mon, 23 Feb 2026 10:36:36 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 00/11] Zero page->private when freeing pages To: Matthew Wilcox , Zi Yan Cc: linux-mm@kvack.org, Andrew Morton , linux-erofs@lists.ozlabs.org, linux-block@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Lorenzo Stoakes , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Jason Xing , Yushan Zhou , "Masami Hiramatsu (Google)" , Vlastimil Babka , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , Christian Koenig , Huang Rui , Matthew Auld , Matthew Brost , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Jens Axboe , Christian Brauner , K Prateek Nayak , Davidlohr Bueso , Eric Sandeen , Greg Kroah-Hartman , =?UTF-8?Q?Arve_Hj=C3=B8nnev=C3=A5g?= , Todd Kjos , Carlos Llamas , Alice Ryhl , Damien Le Moal , Johannes Thumshirn , Dennis Zhou , Tejun Heo , Gao Xiang , Yue Hu , Jeffle Xu , Sandeep Dhavale , Hongbo Li , Chunhai Guo References: <20260223032641.1859381-1-ziy@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: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: B2ECA100003 X-Stat-Signature: xycxyiodg96164mmjewjc8qe3f8x3qdz X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1771839414-565192 X-HE-Meta: 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 VLH1BUE9 1vKpkaPUHKWOU539TJtyiSma9AaTLTtbEZxyhnxb3wYURaOHVKxgHgQGyK+dlpvAJBSAMrboyecg53jxq2J4stqWEQjlOzsOeebOZTMUF0xUaZ/VDAD5wur9iTuIXIIq0eZDAlG66id+rO1npeRO9DjWDVoN0Lv4eqwO8qQJuF8EsOV7/QSZxpnRbhBdU0ZKlFkYa1TPZZz6KG5qi5UDsRp1azGb4GWyl+5SMhWbimirqxshgtn2wXgT2QwG4AGaN4bc8dshcb7YT2Kk0YJYECcY+yg== 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 2/23/26 05:28, Matthew Wilcox wrote: > On Sun, Feb 22, 2026 at 10:26:30PM -0500, Zi Yan wrote: >> Based on a recent discussion with David Hildenbrand on page->private >> is not zero when a page is freed[1], this patchset is trying to fix all >> users do not zero ->private when freeing a page and add checks to make >> sure all freed pages have ->private set to zero. For compound pages, >> both head page and tail pages need to have ->private set to zero. > > Sorry, I didn't notice this conversation. It seems entirely unnecessary > to me to zero out page->private before freeing. > > I'm a bit confused that ac1ea219590c was needed too; I thought we > cleared page->private in the allocation path, and I don't see why > it needs to be cleared in the freeing path. split_page() should be > clearing page->private. See discussion at https://lore.kernel.org/linux-mm/cbc3b5b3-09b5-4e3c-99f0-a1f67582afff@kernel.org/ > > Can we discuss this at the THP Cabal meeting on Wednesday? I don't > think that introducing this new rule that page->private must be cleared > by the users is a good idea. The benefit is that only the users that really use page->private will also zero it out. This implies that all pages that enter+leave the page allocator will have page->private initialized and we can also likely do: diff --git a/mm/internal.h b/mm/internal.h index 9e0577413087..4ecdae78e0d2 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -724,7 +724,6 @@ static inline void prep_compound_tail(struct page *head, int tail_idx) p->mapping = TAIL_MAPPING; set_compound_head(p, head); - set_page_private(p, 0); } extern void prep_compound_page(struct page *page, unsigned int order); Which is rather nice. -- Cheers, David