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 0D824C54731 for ; Tue, 27 Aug 2024 15:38:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 98A986B007B; Tue, 27 Aug 2024 11:38:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9138F6B0083; Tue, 27 Aug 2024 11:38:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 73F486B008A; Tue, 27 Aug 2024 11:38:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 524A86B007B for ; Tue, 27 Aug 2024 11:38:38 -0400 (EDT) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id DE45E141991 for ; Tue, 27 Aug 2024 15:38:37 +0000 (UTC) X-FDA: 82498432674.15.841EB6A Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf16.hostedemail.com (Postfix) with ESMTP id A03AA18002A for ; Tue, 27 Aug 2024 15:38:35 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="L/cvwJaL"; spf=pass (imf16.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-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1724773071; a=rsa-sha256; cv=none; b=hNyPlxeATOLe5Hmh2TEbZnfq7xAVWc9R1Z8GjVfVhr7+Yn75PGDJnuhEnc3OjcH4UsQc8w gEduNA7TBfK9MD/C2ShqUUtd5BGWwlVMnv8rrMr8mZP/Ycmmao02lgQhytLUUWFhIqWWyt /bqZgrfKK180yrbra7ap1Q1moYbrxw0= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="L/cvwJaL"; spf=pass (imf16.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=1724773071; 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=6SRBgYD6RM9Cd9opy/T2UdfkWs8ClKY7nzobJY9kR0o=; b=OLgdIN07lLYmv/i58J2ZEYNineHs/16dSg/0VJjIPnv43F5UP2htivKgy7Dk7eyiZpTxcd ZofdtR2G7/foFRnlt1R79D3BOs+ttrBw9LvdOULwJfHbeyUG3F6ynFVvuXn9dx86PwDwp8 u9iC8Fp5/+/HhXmUFi3gUpiqp/pDBBw= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1724773115; 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=6SRBgYD6RM9Cd9opy/T2UdfkWs8ClKY7nzobJY9kR0o=; b=L/cvwJaLKWcGglNxAn9wdELGDa4Hp5SQ4X6e0TI5p1tuYoNaQ2/V0VJz34vs0ZLM+BLvu4 i4Q0rR5F/amTsiVSO/BnPDxSHeve5BDUiS6HLMg1IBVrCKfLpMrkbzdwm8dpiJc9n7ZQbf 7bE4T3ofjjYFEBelZJpIUUq58IAwg4Y= 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-590-G0mydWiuNNmqM4DAKvrj3Q-1; Tue, 27 Aug 2024 11:38:33 -0400 X-MC-Unique: G0mydWiuNNmqM4DAKvrj3Q-1 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-371b187634fso3096344f8f.0 for ; Tue, 27 Aug 2024 08:38:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724773112; x=1725377912; 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=6SRBgYD6RM9Cd9opy/T2UdfkWs8ClKY7nzobJY9kR0o=; b=KHW8kmrdq4Bfsrmglbd/468KFsGY55HXzI9dA+bLFksreyAhDZOPZ/x1BFyYQSswRY 9f74qMhF9T8NQCFmbg2ebln1qe92UxU6nts6gzxWF0JbqZsm6pMNkwwrB93il9JeA3dR 8CKdmmiJgKG0sNa7AzgHkAMsZlo+FbnhI1orwRv5RnOtPtm/MbLtGjUBY0fdwCI1Vk8c ckjscV03k7QRvxsSu2bWFKsrSmEN6IPa5ummPyEk4xEZ7y4bNwiSpuZe7JPCBuxgeX5z 2JJ0FLYI2zdGGKy5LOwP0tJEwBlPwLGpNx00ex0Jr/jqg2fguA58WCPAu6yxVcxBjXvr zPJA== X-Forwarded-Encrypted: i=1; AJvYcCWYFTpuo0Dlmx9LaX5L3p4cFxVQ7wB3OpqkhyxQAjQHgvjfeiD/5KhSC0QmpgNc3SWqFXqwi+RaOQ==@kvack.org X-Gm-Message-State: AOJu0Yw4l6pw1qPQw9D3cABtosa+eNNwRUyFTSVtVC84HDyk3sN64WPM k7gRZ+hKoOx0CgKOV3zqZH93999QR8PAJLoDXBV9lFVnbJg5/R2epMq8XMIjNZCptRnz5qtMD6G SZAVlQamD4NfPsHhrKTfbE0CrfkDp5tSb8u42dpVhFM1xjHip X-Received: by 2002:adf:e009:0:b0:367:940b:b662 with SMTP id ffacd0b85a97d-3748c847b4amr1618695f8f.31.1724773112304; Tue, 27 Aug 2024 08:38:32 -0700 (PDT) X-Google-Smtp-Source: AGHT+IG7yuz/K7BHtJDX4WBGuOKswdkGUEp7TeccNSj6NuI8p2UlVaptfKmy62EBlJpcPQOnitqt3Q== X-Received: by 2002:adf:e009:0:b0:367:940b:b662 with SMTP id ffacd0b85a97d-3748c847b4amr1618674f8f.31.1724773111396; Tue, 27 Aug 2024 08:38:31 -0700 (PDT) Received: from ?IPV6:2003:cb:c742:a100:9dd2:c523:f5fd:da19? (p200300cbc742a1009dd2c523f5fdda19.dip0.t-ipconnect.de. [2003:cb:c742:a100:9dd2:c523:f5fd:da19]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-373081ffb7csm13382647f8f.82.2024.08.27.08.38.30 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 27 Aug 2024 08:38:30 -0700 (PDT) Message-ID: Date: Tue, 27 Aug 2024 17:38:30 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 5/5] mm: memory_hotplug: unify Huge/LRU/non-LRU movable folio isolation To: Kefeng Wang , Andrew Morton Cc: Oscar Salvador , Miaohe Lin , Naoya Horiguchi , linux-mm@kvack.org References: <20240817084941.2375713-1-wangkefeng.wang@huawei.com> <20240817084941.2375713-6-wangkefeng.wang@huawei.com> <81c2219f-5dcd-4838-8c8d-767b7ff9f714@redhat.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: 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: 8bit X-Stat-Signature: kt8fr4cmrd7sgfgpg33cpc4o5iwosqrd X-Rspamd-Queue-Id: A03AA18002A X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1724773115-599451 X-HE-Meta: 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 bUwBeKEX 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000053, 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 27.08.24 17:35, Kefeng Wang wrote: > > > On 2024/8/27 23:10, David Hildenbrand wrote: >> On 27.08.24 03:26, Kefeng Wang wrote: >>> >>> >>> On 2024/8/26 22:55, David Hildenbrand wrote: >>>> On 17.08.24 10:49, Kefeng Wang wrote: >>>>> Use the isolate_folio_to_list() to unify hugetlb/LRU/non-LRU >>>>> folio isolation, which cleanup code a bit and save a few calls >>>>> to compound_head(). >>>>> >>>>> Signed-off-by: Kefeng Wang >>>>> --- > > ... >>>> Hm, remind me why we are changing the hugetlb code to not take a >>>> reference here? It does look odd. >>> >>> Different from folio_isolate_lru(), isolate_hugetlb() will check folio >>> and try get a reference of folio after get hugetlb_lock, other hugetlb >>> operation protected by this big lock too, so no need to take a reference >>> here. >> >> But this hugetlb-special casing looks quite ... special TBH. >> >> Is there no way to avoid it? >> >> I'd prefer something like the following, with a comment >> >> if (hugetlb) >>     /* >>      * We also want to migrate hugetlb folios that span multiple >>          * memory blocks. So use whatever head page we identified. >>      */ >>     folio = folio_try_get(folio); >> else >>     folio = folio_get_nontail_page(page); >> >> if (!folio) >>     continue; >> >> >> And then just dropping the reference unconditionally. >> >> Is there a problem with that? Optimizing for hugetlb references during >> migration is not worth the trouble. >> >> >> But now I wonder, why we not simply unconditionally do a folio_try_get() > > Yes, I use folio_get_nontail_page() and folio_put() unconditionally in v1, Yes, that part I remember. > this will skip tail page, not consistent with previous behavior for > hugetlb, so I change to current way, but for migration, use > folio_try_get()/folio_put() is enough since we always migrate the whole > folio, it will be more simple. I'm wondering if anything relies on the folio_get_nontail_page() part, but I cannot really think "what" that should be. Using folio_try_get() would be much simpler: we have a page, we want to migrate it away, to do that we have to migrate the folio (wherever that starts or ends). Also, make sure to test with free hugetlb folios. > I will push an additional fix to v3, > which just sent a couple of hours ago. Feel free to send a fixup for v2 instead. -- Cheers, David / dhildenb