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 D928DF506D7 for ; Mon, 16 Mar 2026 14:15:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 48C016B02B0; Mon, 16 Mar 2026 10:15:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 43A236B02B2; Mon, 16 Mar 2026 10:15:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3460A6B02B3; Mon, 16 Mar 2026 10:15:28 -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 23E3E6B02B0 for ; Mon, 16 Mar 2026 10:15:28 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id C8299160274 for ; Mon, 16 Mar 2026 14:15:27 +0000 (UTC) X-FDA: 84552123894.07.C3DDCA1 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf24.hostedemail.com (Postfix) with ESMTP id EC8BB18000E for ; Mon, 16 Mar 2026 14:15:25 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=BowH4afH; spf=pass (imf24.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=1773670526; 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=Fl8JvjgcLDK4j+UfwfT33Rdw6sd0dXM6mZ1n3xvVCkY=; b=OGuxnsXqP4/w2xXzgpcDMezm0kvqRS/xhX8MXknzPI28DkQYjNA8Ma3TP9tdqE+9S6Zoi/ mIQnIu6cZbCh4a1B8fE4C2s2fZyJVw+8VUYY52OrV036X5Mm6wVyTXSTqIaFJx6fccWZ59 6h8yYPG5EX6Mt3KwAfdsq0rH1AwE+6Q= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1773670526; a=rsa-sha256; cv=none; b=YFhthQ8RZHwWVmdeTzLp5MTFrMsXsfiA/fDHliBsF3Xjl94UeHmSWjU5R+dyEvgClH40mq JilFxOgE80K/2NfgMn55XYVHvV9RXmLPQ/hGnB1tBgxCAyv1PM7ZK7Rb0bEOX6oTOvTwk6 npokDSnTECUNtU8OfF03pWrIrVuo1lU= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=BowH4afH; spf=pass (imf24.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 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id DFAAB43C59; Mon, 16 Mar 2026 14:15:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 672A1C19421; Mon, 16 Mar 2026 14:15:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773670524; bh=AMYLIbC0XsyIeE592yVqLMzFEBrfw2qSx6eHBAsjStk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=BowH4afH8xNOvUvPXoGnX3QiYu8G73nqHWtCjBoZU+TFzL04LqlcQ1DpKNBrWW3FZ +QX4rLlHxR8sluW7mz9nTROilho5xtAEMDGtkUjYE8UicGlscjLRmfWhUjdjoyvy0h t4w8HKjV0QGMecNN40YAKUHsKE9rLtQGt6JspdvvYpstALRuhCUTjCTljy4MNEDoQT oVDVC2Ymws8d8S97UvIvVqQ0YJCKNcfOG23HdZNoUk3z+yrYp367/8xA5lpl/H0Hos g5XFzt2ffsv8ex0HQ3AFCpSv+PwNvKGJ+fVx9kQUco0SG9bhb13I7h9CngzrwMTuv+ QwRj/MDzncpYQ== Message-ID: <86f611cb-1292-44e4-b629-6503135d33ca@kernel.org> Date: Mon, 16 Mar 2026 15:15:18 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 1/5] mm: rmap: support batched checks of the references for large folios To: Baolin Wang , Barry Song <21cnbao@gmail.com> Cc: akpm@linux-foundation.org, catalin.marinas@arm.com, will@kernel.org, lorenzo.stoakes@oracle.com, ryan.roberts@arm.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, riel@surriel.com, harry.yoo@oracle.com, jannh@google.com, willy@infradead.org, dev.jain@arm.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <12132694536834262062d1fb304f8f8a064b6750.1770645603.git.baolin.wang@linux.alibaba.com> <43831628-a00f-4292-9797-cb96a029bb00@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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: EC8BB18000E X-Stat-Signature: yrtika9jwooaj87ryib7eqhypqq4qpdj X-HE-Tag: 1773670525-345283 X-HE-Meta: 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 roRb6S7y uMRJdf4yvMjD49eKM7G62MKiCmUs7qkqbWcCTK2S7Vr3xE8wiPDTgVfiAqaCb9M8u9aD5eEXs5YrBrv4nXV0KzyzBilcaq2QnB5dJ2bWB3rQDeMKgof5FQ3KyzFSgFaJ/AA2aT2/XfHzRqBJNJzqswY33q9QR1SIxYOr6N0/yhPuwbV6kbAY9LeLaXCr3CgDjwqZJkvH2V9nIvO9glT+GzVyQ5+UYHW5B3Pb473M31Sk4pgLlWbsCZ4OBZ68JPcHL5ybvv+FFkSzIhVVTAXVd9B19xyAQSiUXCVk6 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 3/16/26 07:25, Baolin Wang wrote: > > > On 3/10/26 4:17 PM, David Hildenbrand (Arm) wrote: >> On 3/10/26 02:37, Baolin Wang wrote: >>> >>> >>> >>> I understand your point. I’m concerned that I can’t test this patch on >>> every architecture to validate the benefits. Anyway, let me try this on >>> my X86 machine first. >> >> In any case, please make that a follow-up patch :) > > Sure. However, after investigating RISC‑V and x86, I found that > ptep_clear_flush_young() does not flush the TLB on these architectures: > > int ptep_clear_flush_young(struct vm_area_struct *vma, >                unsigned long address, pte_t *ptep) > { >     /* >      * On x86 CPUs, clearing the accessed bit without a TLB flush >      * doesn't cause data corruption. [ It could cause incorrect >      * page aging and the (mistaken) reclaim of hot pages, but the >      * chance of that should be relatively low. ] >      * >      * So as a performance optimization don't flush the TLB when >      * clearing the accessed bit, it will eventually be flushed by >      * a context switch or a VM operation anyway. [ In the rare >      * event of it not getting flushed for a long time the delay >      * shouldn't really matter because there's no real memory >      * pressure for swapout to react to. ] >      */ >     return ptep_test_and_clear_young(vma, address, ptep); > } You'd probably want an arch helper then, that tells you whether a flush_tlb_range() after ptep_test_and_clear_young() is required. Or some special flush_tlb_range() helper. I agree that it requires more work. -- Cheers, David