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 39072F9D0CA for ; Tue, 14 Apr 2026 12:17:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 321816B0088; Tue, 14 Apr 2026 08:17:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2F9376B008A; Tue, 14 Apr 2026 08:17:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 20F5C6B0092; Tue, 14 Apr 2026 08:17:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 130266B0088 for ; Tue, 14 Apr 2026 08:17:41 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id A28BB1A056C for ; Tue, 14 Apr 2026 12:17:40 +0000 (UTC) X-FDA: 84657062280.18.6F6C5E5 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf10.hostedemail.com (Postfix) with ESMTP id BC5ECC000B for ; Tue, 14 Apr 2026 12:17:38 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=MsjpU+x1; spf=pass (imf10.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-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=MsjpU+x1; spf=pass (imf10.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; s=arc-20220608; d=hostedemail.com; t=1776169058; a=rsa-sha256; cv=none; b=nC2JIqpwglARsDovd3Es0HgoJAZVvQeqWahLKc3Jgj2H9YKN5Tf6aKPJaIbCzPg/BumrnA S+p8BvAbS1GngPshpC1qNINI/kBMmar7obJnpSBVmNtB4Qp006kWHLPElRM1SUtGSnPsdQ 149EIH2FooVpMm83GIDvwxB6sHM8i/Y= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1776169058; 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=GrSdEF+JqZFoj7agI/H7KkVJBrY/vQ9XnnPksvwoWxU=; b=pZBuEBbjmgY1EFGnxTEIMNsu6X90l6ZTFKIeFjCU7oXCDPub3riFr5kScJhDq2jsQO9LE8 qzbBgw3D4EV7eY9M8FNXzOMqwQo4SOpvTxvCcT/WiVWd1lEwWWGnNHziPn5RUs5irZyKZV NRJjH8hXVUaV9cV80bj+3y8bVZUIywc= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 9E39A43720; Tue, 14 Apr 2026 12:17:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C4B12C19425; Tue, 14 Apr 2026 12:17:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776169057; bh=oC6Dg87jkmwO4/6ynndKIVQo/FD4gcqiu6meUZwGQv8=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=MsjpU+x1PFgbJdR0CpqaWmfljI0WBVQGF+x8L1knWKizXH5VsJie2EoNxxMEpuUyt Xp4mjJfpXDq9FP/zLKxEW7ZFgTCjn7QMdayaBbx75OZLkDKAE14BLmOnnAuPLGGtzD 84MDeLOxxmPt1xmhoOJm/ztGarQH7eF4n8n53Amanzjy19DNCwlkMjL1kg72vWtE3I Wp1A7NHFOw2pGwLuaOvTYgSpLoLOZaXeKXUApoiZP/PpmBfp8WT/WhiLzK0HeE9Ec7 HPqT2aNqvNVuD81j1jnxVZc9A0aBJcVn8W3AcV7IT9pL2lhwPxuk25iIgjeYfqO1eq KdceBkjARWs1Q== Message-ID: <90d0abf6-fec4-439e-a7b3-756e3cdcba6b@kernel.org> Date: Tue, 14 Apr 2026 14:17:31 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] mm/sparse: Remove sparse buffer pre-allocation mechanism To: Mike Rapoport Cc: Muchun Song , Andrew Morton , Muchun Song , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260410092419.2446420-1-songmuchun@bytedance.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 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: BC5ECC000B X-Stat-Signature: aujccwum7ewczih3uns1edrfamh58114 X-Rspam-User: X-HE-Tag: 1776169058-488488 X-HE-Meta: U2FsdGVkX19FnnZB1WWx+lEKYicTL/x0yBd0IZG8gewZdo/qTt+WbOJYl6tl7+L49WqqyTBGI9lRxDbS256YSVmPxfXQsIMYEWfOU2wnPJTui6GvD7Nw850Y8ZbkgJD9+C/dhF62QrhYpFRFjcoKcyrWAWqVkjhRsFCYMVexapzJzg11iR4m64AoBV2EOEWbrtxrBIeSYBnflaf2EiOlRhHy2eJGoNgfJKGKjJ0gjfJLvda4nEvTRKaPfpJEtuPjN9JDsYRo5EAQxnSZguA0Mu0A98PDADLCp/IfnavgzJlZo0iYypCoWhpqFaX8tnwhKLYNgWTvXSu1l1CIuyI30F+JoPsisTQ88AcD8xHCb8wjLkSdEV1WDex9Lk3NQJKB66Thx59bXcaOqH0E+g7BcM8S1kXCJQo8hKCV5795mWi/MdqM7VyfvRahUe5r7wlTMpN8icPsbjIkis45+RxjLnS04TZ8h6CHsAAnKpZsr8S/tXi9hVGf7wAE9mc/TZ4Sx1ZDNj0TzU3frmHNU7SSRoiYNyTabT8AhjtMZO0lhJXhJRWysxVKSYYPSqZkk81VBkXBJ7mnnAWLdNkdP6eFNzgxPWsWa9AwvdD/hiCaMaspdEE9S+9ioglKRMFoJTg723qAG9coKcdrat2u+3a+Qu84jt1eC9e0RIHlgKluyiR/5GeijRpEPp6OFWnl6aZdctFhdJuwnEplBBePH2Y8aMK/aXkBiuAwxyUVgTgshSm29m36Pkzhp3s6zzcrtBqCbXxARfOwAkIs94vTZuzFhoQ+m5TVdjv4AIjItOOWX7Nq4jSizP7DaN+OAV5ILr/Pi/sEhA9lbTSEjDRej78kN3Hg5m3ymi65oedWV8uhR95M7oyZyPB7IkhfyqGyZJaCX+g7OpJamfxkwTU5PJBJBroTVbX1GPWOSbWvTq5nZEw2mbFgFNf0jazq+aR9arEsKWhedX46qdZ06aMcabk eE1S/HXj IQWBV6Mk/31mfil3dQaLQw5+yF/Xzyjae2wx/0e9R+0uzwnSKtcSMOcxpbU7EYEysDbqka+ya7kl6SZxoqprTP+REJXG/NI8uh7/KjT3FPov7hpbbitnhkdB1bkG29IGakV1a7koccKzb0qyATbdo2IijMO9EIoIqN+5jJpcays4+25GMJGSsdCsQmETRSJhdFA/OaOtqb43byOBQZ3dcdRRtD9lzw54toZeySkcrLMYErvTAgPCK7ASrUe2W5gjVdf3O Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/14/26 14:11, Mike Rapoport wrote: > On Mon, Apr 13, 2026 at 09:02:43PM +0200, David Hildenbrand (Arm) wrote: >>> - >>> -void * __meminit sparse_buffer_alloc(unsigned long size) >>> -{ >>> - void *ptr = NULL; >>> - >>> - if (sparsemap_buf) { >>> - ptr = (void *) roundup((unsigned long)sparsemap_buf, size); >>> - if (ptr + size > sparsemap_buf_end) >>> - ptr = NULL; >>> - else { >>> - /* Free redundant aligned space */ >>> - if ((unsigned long)(ptr - sparsemap_buf) > 0) >>> - sparse_buffer_free((unsigned long)(ptr - sparsemap_buf)); >>> - sparsemap_buf = ptr + size; >> >> This code implied, that we would usually get contiguous memory sections >> (on the same node) to have contiguous PFNs in the SPARSE !VMEMMAP case. >> That will no longer be the case (reliably). >> >> The code must be prepared to handle that, so I guess that is fine. And >> we don't care that much about SPARSE !VMEMMAP. > > I've started to hunt them down ;-P Nice :) -- Cheers, David