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 75D36FED3F2 for ; Fri, 24 Apr 2026 18:34:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E2AC56B0092; Fri, 24 Apr 2026 14:34:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E02396B0093; Fri, 24 Apr 2026 14:34:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D18736B0095; Fri, 24 Apr 2026 14:34:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id C22936B0092 for ; Fri, 24 Apr 2026 14:34:02 -0400 (EDT) Received: from smtpin27.hostedemail.com (lb01b-stub [10.200.18.250]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 87CAE402BB for ; Fri, 24 Apr 2026 18:34:02 +0000 (UTC) X-FDA: 84694298724.27.D1D4D64 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf22.hostedemail.com (Postfix) with ESMTP id D7CE8C0008 for ; Fri, 24 Apr 2026 18:34:00 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=sKA0DITd; spf=pass (imf22.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=1777055640; 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=TmWVG+MDzcAoy+j4BlMNgcs31+NIvg5mQI315xzbz8M=; b=jQX+eXuRVMFLRa4kPqAxuBGbwnMsO06dA+xiudVoIvn7txhgh+Hej00afo62wDu+NOQ1O+ r0CO8u5BA4MMgKC0Tb4t0W4Y/1ydUgDxRmIRPbxBSTapf/3HcPcxDxpv3aRF5060pBMLzm q65Maej2cjS7cQX6fAEr59WQtLNi1t4= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=sKA0DITd; spf=pass (imf22.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-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1777055640; a=rsa-sha256; cv=none; b=VC0fkXG9iyCEMFwjap6+GAlm+P02Rz07h6/5TZCmcgmQkVveaE87C0D40htZERdmYlEhRu pcHe/vse7TnHumD38pwkxVbz8WUBBSjMpF6zOEHw//NBnRiyhTzzh2L9fAKGFBnFWlIUW1 u9jOJRrJkQT9r3ftu4Xb7TwUIzODPAk= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id BB83860123; Fri, 24 Apr 2026 18:33:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A2EC2C2BCB4; Fri, 24 Apr 2026 18:33:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777055639; bh=/eLx7kUbMNf35MbwljFoEAxjWli6DbZEA0fmcECuzY4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=sKA0DITdxCODM2VDwZATIZV/+2Q9QtqKKTgXbCegYwXkeCv1Azbn8CqIHxt8LfhH1 HPKO1kqtZgmbjfcua6vhYps3h6FiKiz57KHM71R+jRGGgRREvijLUAvzgyNlQHwAGW AxV/pmaBrSrFt9O5MG2keZoVNWRyuuq6Xh0DxndarOEmyqixLwoG6+nL+q02jy7f3P 6gX3e1fWep/QK11+v9C6S3lrPJ/83Pi1E8v18aFPl5mZBohsULf15WQtjc33bNgD5p Pyc97vZWzSErPc9V1VxAIwwBCF3/pHOm5qoy9jZcf72RKKtl49JIuIEexQiCFAAwgt Q592MfBIXnWWw== Message-ID: <4e12d67b-60e3-4bf5-a229-43c0d2c62cfb@kernel.org> Date: Fri, 24 Apr 2026 20:33:45 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v3 01/19] mm: thread user_addr through page allocator for cache-friendly zeroing To: "Michael S. Tsirkin" Cc: Gregory Price , linux-kernel@vger.kernel.org, Andrew Morton , Vlastimil Babka , Brendan Jackman , Michal Hocko , Suren Baghdasaryan , Jason Wang , Andrea Arcangeli , linux-mm@kvack.org, virtualization@lists.linux.dev, Johannes Weiner , Zi Yan , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport , "Matthew Wilcox (Oracle)" , Muchun Song , Oscar Salvador , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Ying Huang , Alistair Popple , Hugh Dickins , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , linux-fsdevel@vger.kernel.org References: <9dd9deabd42801f3c344326991d1431c3d8db39d.1776808210.git.mst@redhat.com> <20260422171315-mutt-send-email-mst@kernel.org> <20260423074433-mutt-send-email-mst@kernel.org> <88b0765f-7cfc-4e44-83d2-c01a1755c842@kernel.org> <20260423104120-mutt-send-email-mst@kernel.org> <1ab6e58f-d984-4bae-a343-1b0d3c973ad0@kernel.org> <20260423121222-mutt-send-email-mst@kernel.org> 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: <20260423121222-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: chba8c1zz3phe55zp4nkf61do3of7k1c X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: D7CE8C0008 X-Rspam-User: X-HE-Tag: 1777055640-575990 X-HE-Meta: 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 7I+T4qZ1 4wOrU6H7S/01h6Pong2msTQdgQc6KbjY1rmUZdIoliPItHrmGigzyIqUt0wNvOvyl9zr1rssA71YCH8qVVW7GqIM+d80Fl0BbPjNc/ziLKajGUHfNhkpr//K4s8WctvKqkX2pm8NUHHxF4kTm5nL3aIShHjsDGZrXjkGYmbIZxeZYbQZFu5NRI0lcLwI30xbW+pFrSYL6Ld7W9dSkMq9OYEUpRjvSijtlc03PxEGEpZc36LnN51/z/7hj3a83G01DHdyUx3Hm3JmD7rRdA1iLarQvvuAJQM2YGh+h76ZkV5QAL4i/KkJyPoL2xP+qWg07O81U2WCxSfnSXniBbUPOJJmBuVa0GpBAX3pwaHVkLsqVJts/6n0VmeWHINZHzIJZf1DL Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/23/26 18:13, Michael S. Tsirkin wrote: > On Thu, Apr 23, 2026 at 05:54:26PM +0200, David Hildenbrand (Arm) wrote: >> On 4/23/26 16:46, Michael S. Tsirkin wrote: >>> >>> I just dislike it when things are non orthogonal. >>> People are used to: hugetlb = same perf as THP but more predictable at the cost >>> of being harder to use and using more resources. >>> Here, suddenly, we have an optimization but only for THP. >> >> Note that we also didn't care about user_alloc_needs_zeroing() with hugetlb so far. > > > You mean, that it stays because of the reserved pool? I meant, that if we are running with init_on_free or init_on_alloc, that we end up double-zeroing right now upstream. So nobody cared to optimize that part so far. -- Cheers, David