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 8A15BC48BC4 for ; Wed, 14 Feb 2024 10:55:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 185456B00A2; Wed, 14 Feb 2024 05:55:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 134FD6B00A4; Wed, 14 Feb 2024 05:55:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EF1536B00A5; Wed, 14 Feb 2024 05:55:25 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id E17B96B00A2 for ; Wed, 14 Feb 2024 05:55:25 -0500 (EST) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id ADE621606A3 for ; Wed, 14 Feb 2024 10:55:25 +0000 (UTC) X-FDA: 81790103010.12.844CE09 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf14.hostedemail.com (Postfix) with ESMTP id 510B5100020 for ; Wed, 14 Feb 2024 10:55:23 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="NNFoAF/R"; spf=pass (imf14.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=1707908123; 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=FkG4rFYSar/COgr1ANQgOL3qRnWrGDmTgIrKAH1p2yk=; b=xBO1+2KyJD3yV5HGLIMQ0Ux26aN3A3GYuwyCgMbgIasLxo83mpb3aGiWLRR2qwTTk8oyO0 EgqdgCSgWVpFw3/ug3WqiSzLIq5ZpjoIO2YW4kj3aAUBvF0aAcA27MH9gREF7oKbSTitBc vyHH5VVrsLC1Za2CW5rggWpvmdgYaQU= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1707908123; a=rsa-sha256; cv=none; b=O7eGxhLBIm7NXuIb17WUc8kdv24ebzFyvR0JbWeyoKhaDSWek/Jc1HWUsStP6zHRKOrY8P gPJOPuCYrHYKVanCgocEcCk9Er+hGDU5FeKTiyU2WVJyoy6ttZPEnuQpNq1QREPfomXV+v pceUxMWYIw58hroMObXzz94dgrRtshk= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="NNFoAF/R"; spf=pass (imf14.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=1707908122; 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=FkG4rFYSar/COgr1ANQgOL3qRnWrGDmTgIrKAH1p2yk=; b=NNFoAF/R8e9GPEhWKXcOcWlXvyYE/HS/kkwBVccJy7xJwIUgsG+JAJ9lH2bamxMk05Pv6N dnEmYu8bnwlfuKmS1+XZ0JW4wzReJFOajn8UUIsnTDLe+B0XLwPPGuwMy+j/rCKQwwBCEX CDw4a8+cSeLe2wwr70pIuEZly7Gnwts= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-526-Vap5fPXmODKRa-8jq6fdjA-1; Wed, 14 Feb 2024 05:55:18 -0500 X-MC-Unique: Vap5fPXmODKRa-8jq6fdjA-1 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-33cf40f4c08so12445f8f.0 for ; Wed, 14 Feb 2024 02:55:18 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707908117; x=1708512917; h=content-transfer-encoding:in-reply-to:organization:autocrypt:from :references:cc:to:content-language:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=FkG4rFYSar/COgr1ANQgOL3qRnWrGDmTgIrKAH1p2yk=; b=Y+HijyU3XICzwu0XxAAaeV6ojStEhfc+0VVvtKubJ03EEa7KDFdEqYNemgXkUFW6SB fV14KQD29dG8EcYBQ2/F5pNSB203q+xJC5osugfJjgo4al/aNzmlb76oVnZbasO9AEY+ oSk+fkzlBTO51SZ/Lg/9XSVhsyhrfCJWPbQchquSB0fioaqcsRU8vBAdh9Di2jnt6EAg 0DQa9CI5JbRFmJ2hTRiR8UQ6ULBJl96ka/4gxg44l8uYp4m0YgAZpuLgfF2lvck4pDZq dPThOG7sx3hdFTRHgDOAsz6VClMHlR+XZTcMBTfivXpv4cJ2V3ksxCQ5Q5g4OUJfXHDB ZTQQ== X-Forwarded-Encrypted: i=1; AJvYcCW0PAYj3eR4tQaVyNVjiDHSqaLuJXO1xhU6O2K4Lu6/ssLxS1Qo6r8PNQk9o11vmWUg8u9O35j++jXgdGhrtMkOo8k= X-Gm-Message-State: AOJu0YxC0oB+jKI74xWc9+JOFhYj0oIkjJffXhNTShEz/3btlkuMPsuR mqMt5vSvh0Qq6PHurFKQLypmTG7w1dB8QouzarJZulMdCcwKvtkSa6rPdPTsxA94nSSGEd4iWeZ 7tyzXIPcwQ2+OW2uK7YVt5MmuQjrGWj6kuCKoFzNhRGlGs1Mi X-Received: by 2002:adf:ce03:0:b0:33c:e339:23e4 with SMTP id p3-20020adfce03000000b0033ce33923e4mr1686954wrn.62.1707908117481; Wed, 14 Feb 2024 02:55:17 -0800 (PST) X-Google-Smtp-Source: AGHT+IEXEpBq8Q8ZnFUw1naCQqfidxYnDmHpx6kSBfapsNJ6KX7OVMNFoSQImIEewE+QUkL0vkf4Pw== X-Received: by 2002:adf:ce03:0:b0:33c:e339:23e4 with SMTP id p3-20020adfce03000000b0033ce33923e4mr1686932wrn.62.1707908117063; Wed, 14 Feb 2024 02:55:17 -0800 (PST) X-Forwarded-Encrypted: i=1; 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 Received: from ?IPV6:2003:d8:2f3c:3f00:7177:eb0c:d3d2:4b0e? (p200300d82f3c3f007177eb0cd3d24b0e.dip0.t-ipconnect.de. [2003:d8:2f3c:3f00:7177:eb0c:d3d2:4b0e]) by smtp.gmail.com with ESMTPSA id w13-20020a5d404d000000b0033b4dae972asm11995459wrp.37.2024.02.14.02.55.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 14 Feb 2024 02:55:16 -0800 (PST) Message-ID: <46f61262-e197-456c-97f1-d464ad5688c1@redhat.com> Date: Wed, 14 Feb 2024 11:55:15 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 0/7] Split a folio to any lower order folios To: Ryan Roberts , Zi Yan Cc: "Pankaj Raghav (Samsung)" , linux-mm@kvack.org, "Matthew Wilcox (Oracle)" , Yang Shi , Yu Zhao , "Kirill A . Shutemov" , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Roman Gushchin , Zach O'Keefe , Hugh Dickins , Mcgrof Chamberlain , Andrew Morton , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20240213215520.1048625-1-zi.yan@sent.com> <659e1abb-40d0-42ba-ba0a-8256d7eb1c5a@redhat.com> <66d4b27f-85e4-458e-8d66-54f800c5c65f@arm.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: <66d4b27f-85e4-458e-8d66-54f800c5c65f@arm.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: 510B5100020 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: 5uci7e8sb444h5tupuuegy57is4or8bc X-HE-Tag: 1707908123-297495 X-HE-Meta: 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 RVlE9ftw UQv36dD5V2df66N0+vLgW/TZYxGzKCYkB8TTU0XfZJlDFWedpBDEUxNAdsaa8g+soTflXcefwUvDUKHGyjdvqqm1y+N5DsKIFLupRBz1lPm5trmyN3wuu44KcnOS9BcItqQyoncwl7FKKElPHdzrxz2MShBc3kgRrPedJiq0+rkGG7ZI42MTXLaXKVrvOF8zTB+VlQNkhC+kTEKvf86q35GDil6GJ0O8c5MUXI/8coYk9ANd96BYuE4QDMOImDnJcmeokJP2vOhjTs2nU64KiovNBnBp+OqvcL8GtUp9a8W+fpRveNTMu6iPw5Pitb1LX+o2jdbID2ntIdy8uW9j15pZI1rjAUfmkFfFJ 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 14.02.24 11:50, Ryan Roberts wrote: > On 13/02/2024 22:31, Zi Yan wrote: >> On 13 Feb 2024, at 17:21, David Hildenbrand wrote: >> >>> On 13.02.24 22:55, Zi Yan wrote: >>>> From: Zi Yan >>>> >>>> Hi all, >>>> >>>> File folio supports any order and multi-size THP is upstreamed[1], so both >>>> file and anonymous folios can be >0 order. Currently, split_huge_page() >>>> only splits a huge page to order-0 pages, but splitting to orders higher than >>>> 0 is going to better utilize large folios. In addition, Large Block >>>> Sizes in XFS support would benefit from it[2]. This patchset adds support for >>>> splitting a large folio to any lower order folios and uses it during file >>>> folio truncate operations. >>>> >>>> For Patch 6, Hugh did not like my approach to minimize the number of >>>> folios for truncate[3]. I would like to get more feedback, especially >>>> from FS people, on it to decide whether to keep it or not. >>> >>> I'm curious, would it make sense to exclude the "more" controversial parts (i.e., patch #6) for now, and focus on the XFS use case only? >> >> Sure. Patch 6 was there to make use of split_huge_page_to_list_to_order(). >> Now we have multi-size THP and XFS use cases, it can be dropped. > > What are your plans for how to determine when to split THP and to what order? I > don't see anything in this series that would split anon THP to non-zero order? > > We have talked about using hints from user space in the past (e.g. mremap, > munmap, madvise, etc). But chrome has a use case where it temporarily mprotects > a single (4K) page as part of garbage collection (IIRC). If you eagerly split on > that hint, you will have lost the benefits of the large folio when it later > mprotects back to the original setting. Not only that, splitting will make some of these operations more expensive, possibly with no actual benefit. > > I guess David will suggest this would be a good use case for the khugepaged-lite > machanism we have been talking about. I dunno - it seems wasteful to split then > collapse again. I agree. mprotect() and even madvise(), ... might not be good candidates for splitting. mremap() likely is, if the folio is mapped exclusively. MADV_DONTNEED/munmap()/mlock() might be good candidates (again, if mapped exclusively). This will need a lot of thought I'm afraid (as you say, deferred splitting is another example). -- Cheers, David / dhildenb