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 0D931EA4FC7 for ; Mon, 23 Feb 2026 14:15:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 37A046B0088; Mon, 23 Feb 2026 09:15:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 327696B008A; Mon, 23 Feb 2026 09:15:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 209196B008C; Mon, 23 Feb 2026 09:15:06 -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 0E4EB6B0088 for ; Mon, 23 Feb 2026 09:15:06 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id C56E2B6380 for ; Mon, 23 Feb 2026 14:15:05 +0000 (UTC) X-FDA: 84475918170.09.EB452A0 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf07.hostedemail.com (Postfix) with ESMTP id 0283140015 for ; Mon, 23 Feb 2026 14:15:03 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=lLBRzCGo; spf=pass (imf07.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=1771856104; 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=dBncoYX+4WE3NuQre7Sy0cd4OIe5ZVxDQRulo50h7yI=; b=kwXqm9q5m5a9AdPknLIjAZhVHPdn/dNew/a4y2HVEhl89HFeizLYvDf3S7q238mOtTyDmW 1rK+C01VXe+KLxgCkr2hd9MWlCFuxTXHf2TerDMtBzm/Jj/qEHoFr22Fd5SRQNLi8SCcjm eyq63BDCHmrt04yOj+Jug3kaBCp+JbE= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1771856104; a=rsa-sha256; cv=none; b=LjmF74FD+sxpm3HgFHIJULdvqkhT7YQtddjkyAzpdRLBgOTCPFqwnbNGF9Q+xQInJ9N1mX b3yB+ImqzfUA/HP2wcsUM32g01bbud90Vi3NJOC7HXIGE9SmVT4ETzJdifzM4ziCpdvz6X QJxqWFGXF9e/c8u6yIkWRUM6cHOVDnw= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=lLBRzCGo; spf=pass (imf07.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 1467F600C4; Mon, 23 Feb 2026 14:15:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A05EC116C6; Mon, 23 Feb 2026 14:14:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771856102; bh=cegM+rd3V8p3uUtFz/8+ZfbKtzN5jDE+6Zwct258jo4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=lLBRzCGosADz91G+m0U+M++rBhVB1sFW6A7qsoD9dN6XXO4+s05rc5r3BkVywjZ5w LouVS6a8jmW1Gj25A/6t3W3wDXZHVYkbitm7KjtHu9x53QC8d5jybB2Icd91IbUaRZ umKr2Kpnspd6uvw/1i/lrlCH8f2akdAADKn1LATlqbrPeC1NNpj3rqlPYd5MVtvvpo 3eSvIsPmG26g76HPLL0ubwowOC9ValMICw9XE+rm4z5SFGunW/7vqUvgjWwyOas66+ RA0uMZmzGKuVeostRLNPhCOqUOyNw1aOvZW+Sr1q9m53RRBCNF+1Q1eMPG92ItWQh5 EanKrkGsljLhg== Message-ID: <5105764a-8313-45bd-8b91-8c0ea8cdf077@kernel.org> Date: Mon, 23 Feb 2026 15:14:45 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 00/11] Zero page->private when freeing pages To: =?UTF-8?Q?Christian_K=C3=B6nig?= , Christoph Hellwig , 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 , 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: 8bit X-Rspamd-Queue-Id: 0283140015 X-Stat-Signature: oif8nz9akygro6oqsug75e7jshzhpy4z X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1771856103-889344 X-HE-Meta: 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 YWiIOFDn xgVqzYq3ilVD5vz2Y9yoJOO+9T9EJTURu0Om7AcF4hxfRxyZmu7VNIYa2iqEKd+MnUS2EGVcebc7oLdDY+ktrybVpCamPU5sIF+TjTXKN+72xDOlu6ZzlW7pEXMIK52c626ac02+CeNfRkzag17gGgjjTUre99EeKhDMtrM3gsSOrw8PHTBXxlOkh5whf+6jHY4zlT3vyhj+eAxYkked/tppD5DOtv4bvth1kzy9QoJISFV9v9NVHib+l3C0rblmqq89y7BLSur+pOuHfWHECi4Bgag== 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 15:06, Christian König wrote: > On 2/23/26 14:46, Christoph Hellwig wrote: >> On Sun, Feb 22, 2026 at 10:26:30PM -0500, Zi Yan wrote: >>> Hi all, >>> >>> 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. >> >> Requiring the user to clear a field before freeing is just a way to >> awkward interface. Don't do that. > > Completely agree. This is just asking for trouble. > > The cache line(s) backing this struct page are most likely accessed anyway on free/alloc. So I don't see much extra overhead. I think the question is more around handling non-head pages when freeing larger orders. But maybe the overhead of zeroing page->private it there as well in __free_pages_prepare() is tolerable. I'll note, though, that we already require page->mapping and page->memcg_data of pages to be zeroed by the caller, so it's not completely crazy. (see page_expected_state) -- Cheers, David