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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2EE9AC5321E for ; Mon, 26 Aug 2024 15:33:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 947496B0088; Mon, 26 Aug 2024 11:33:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8D01A6B0089; Mon, 26 Aug 2024 11:33:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7227C6B008A; Mon, 26 Aug 2024 11:33:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 4FD806B0088 for ; Mon, 26 Aug 2024 11:33:41 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 02784120FB5 for ; Mon, 26 Aug 2024 15:33:40 +0000 (UTC) X-FDA: 82494791442.19.48B20D3 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf25.hostedemail.com (Postfix) with ESMTP id A7FE2A0015 for ; Mon, 26 Aug 2024 15:33:38 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=JW7Xb8H4; spf=pass (imf25.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1724686334; 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=fLHVmwuLAYPsFURDKjEb+NeYe5prtzLVT02SsD4UDUM=; b=nfxRdSUaJ45TOL5myu4AjH256bDta7Lh165CTy89t536I3yiZSHG/nOvsNsjR9BbaAZuv5 OefncRnec+rYueykCjBXAfTp5nmMuAT1xQ6QfwN5B+zlEP+jLC5O3YI1YDaCMYyb41nIwD nsRlpy/R+Xc/nzPa42cGU5ZdKQq0ib8= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1724686334; a=rsa-sha256; cv=none; b=SP4B5InTrLUTzOj7niQ9cGuEayzyo6K+yLHAJcVekJ28ZCexqZLTz1dDsrgaULlYOBcQhH gBeU7uCC64fA6DRmYFIDW/A12vpOgpRQW9pYSOAYRjIXzvtjmBfsHalQgN2Q7PwkWKyWUS lSyWIPfaeNzEJX2jULuI/4LFt7tZ5GQ= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=JW7Xb8H4; spf=pass (imf25.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1724686418; h=from:from: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:autocrypt:autocrypt; bh=fLHVmwuLAYPsFURDKjEb+NeYe5prtzLVT02SsD4UDUM=; b=JW7Xb8H4UsQ50INBZJghvY93uMRSzF9ceCuNmnGf6OsC8CPB/IzTPJrhUmP2Ega5BXWSQW MLtoOOZyaySDTf5Im4uJbzJQMzwWd0GN6wPMYypoawmu1ISMYswKF649uJQDhRs5oa+XrO qt0XgpN6uXIJTmJg/U2PTvbIyuzfR54= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-400-W8AhqlVDOLm2wSfIV2PhcA-1; Mon, 26 Aug 2024 11:33:35 -0400 X-MC-Unique: W8AhqlVDOLm2wSfIV2PhcA-1 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-3718baf35e0so2484543f8f.1 for ; Mon, 26 Aug 2024 08:33:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724686414; x=1725291214; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:from:references:cc:to:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=fLHVmwuLAYPsFURDKjEb+NeYe5prtzLVT02SsD4UDUM=; b=qrfuZiELjnU+i4ZrzMQHio8lBzFjtN8Z3/BAiYuBf6DGRLMSY0YVzE5Ye25Ec7pCwI LwkepH48/fq+UhB4OTMq8f1Cx8jZ49X1sfuYkfFgcLIPdBR6lJ4StrkhWOJEwmC+2bbJ P1l5URazMQX89FrtU0IYSbmcg979gT05m6r09TIFHpdz9ESCzMTwUm59VjkxyY8lm+cS /n7zHVsl1ZcTbBOzdcmMPCkKBIdG58ANhjnHwRq12m7lSull3QFJES5wb36KueOSYp8i UNs86KoqTeyU8XJycI3YFxIsGXjjli5vUsg6mqW+ku6lM1eJpwjk98Sw61d+MVMqebpX X2GA== X-Forwarded-Encrypted: i=1; AJvYcCXmd8h+fLwlfEDIdRmDhV3KBPePnoQds2SY6ddZ1KbbS7SeqDcrEL6IwYd14w192bx8vo3DyS5E3Q==@kvack.org X-Gm-Message-State: AOJu0YwACIJnv5G7InU9Cyl098E1P2t9wiAJke/PzZgfcdhjkZrpz1v/ jHxGwBHZ2EZ+YKWPehSrxFzM5XIk9qYqabzaFr7K8V/GbEoNVRUiRowY5mZfb95qglYeO675YAH MceFT6wCZ+WZHhjoooL3BIrorb6QVWAufvpGIfJV8ER8705tB X-Received: by 2002:a5d:58fb:0:b0:371:7dda:d7d9 with SMTP id ffacd0b85a97d-373118400c7mr7060077f8f.9.1724686414514; Mon, 26 Aug 2024 08:33:34 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHytmu9SRRnL82xMRuRcaexgdIVoLY9mV2pWJmUW8w6VZNMmeRxH8CESB56unxuK81kkNwCqA== X-Received: by 2002:a5d:58fb:0:b0:371:7dda:d7d9 with SMTP id ffacd0b85a97d-373118400c7mr7060032f8f.9.1724686413712; Mon, 26 Aug 2024 08:33:33 -0700 (PDT) Received: from [192.168.3.141] (p4ff23ced.dip0.t-ipconnect.de. [79.242.60.237]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-37308110436sm11025885f8f.11.2024.08.26.08.33.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 26 Aug 2024 08:33:33 -0700 (PDT) Message-ID: <0b7ca0c2-7a64-4d0e-aa18-2fc4257c199e@redhat.com> Date: Mon, 26 Aug 2024 17:33:23 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 05/14] mm: khugepaged: __collapse_huge_page_swapin() use pte_offset_map_ro_nolock() To: Qi Zheng , hughd@google.com, willy@infradead.org, muchun.song@linux.dev, vbabka@kernel.org, akpm@linux-foundation.org, rppt@kernel.org, vishal.moola@gmail.com, peterx@redhat.com, ryan.roberts@arm.com, christophe.leroy2@cs-soprasteria.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org References: <2b7dceaa12da273c6decf92e3bf2ebc4f4e85ec5.1724310149.git.zhengqi.arch@bytedance.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <2b7dceaa12da273c6decf92e3bf2ebc4f4e85ec5.1724310149.git.zhengqi.arch@bytedance.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: A7FE2A0015 X-Stat-Signature: pqq5d4tkwgh3x97j41isyfcx4ycr6jrs X-Rspamd-Server: rspam09 X-Rspam-User: X-HE-Tag: 1724686418-62355 X-HE-Meta: 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 1n8kL27H 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 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 22.08.24 09:13, Qi Zheng wrote: > In __collapse_huge_page_swapin(), we just use the ptl for pte_same() check > in do_swap_page(). In other places, we directly use pte_offset_map_lock(), > so convert it to using pte_offset_map_ro_nolock(). > > Signed-off-by: Qi Zheng > --- > mm/khugepaged.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 4a83c40d90538..53bfa7f4b7f82 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -1011,7 +1011,11 @@ static int __collapse_huge_page_swapin(struct mm_struct *mm, > }; > > if (!pte++) { > - pte = pte_offset_map_nolock(mm, pmd, address, &ptl); > + /* > + * Here the ptl is only used to check pte_same() in > + * do_swap_page(), so readonly version is enough. > + */ > + pte = pte_offset_map_ro_nolock(mm, pmd, address, &ptl); > if (!pte) { > mmap_read_unlock(mm); > result = SCAN_PMD_NULL; Suboptimal that the pteval comparison + unmap is buried in do_swap_page(). Moving that to the caller is also not significantly better ... Acked-by: David Hildenbrand -- Cheers, David / dhildenb