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 C2B58E77184 for ; Tue, 17 Dec 2024 11:56:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 59D968D0002; Tue, 17 Dec 2024 06:56:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 54DDA8D0001; Tue, 17 Dec 2024 06:56:57 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2B6128D0002; Tue, 17 Dec 2024 06:56:57 -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 0932A8D0001 for ; Tue, 17 Dec 2024 06:56:57 -0500 (EST) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 004561A06C5 for ; Tue, 17 Dec 2024 11:56:48 +0000 (UTC) X-FDA: 82904297868.01.8F8F1EE Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf03.hostedemail.com (Postfix) with ESMTP id B37242000F for ; Tue, 17 Dec 2024 11:56:32 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=U9JwgUdr; spf=pass (imf03.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 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=1734436586; 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=4j3RJ6u8WKht0eWYFAXC4mdKyekBt3cyxE0dVaW09rM=; b=FjRjg0lUEhJHI28hrw8GpA018zEcySEMKNFbiJ3PjttcSytgW5RS4o0hzfP9zPuJ5F+5mG h9vAMx4D2LJTWf9ZYLb3cpXz242VMdmSmvNuVb1+hfTmRYHXQivCEvCNEE0alyAt5UxIMj QS4OqTogvzstMZ/zMSScTHY5Z243mRU= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1734436586; a=rsa-sha256; cv=none; b=i3RNlu3A2raCLWUIKKfp36AL6PiOMapeC2znWsPlhx+xsscvA4hh1YtO7SDdLjzXBpy81D Eumm4MleSpMmmW0POGmp+eccJaRQOfkaA/WqInqaFplIDWEMQAaPm3yh72bOVIRUKm+Y5+ 7e63gshLnHrVLDy4SmiJrimb4Z33naY= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=U9JwgUdr; spf=pass (imf03.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 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=1734436605; 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=4j3RJ6u8WKht0eWYFAXC4mdKyekBt3cyxE0dVaW09rM=; b=U9JwgUdrc+WJT4lWhL0X7C4QQAOcZ2lAMP7Tg7UL7hnbQQPpKhoCFyOcGtB6URMbwtiaEa oyOAMwVtn1iFpHERPiF2GYwAJkUa3BQcYrjBgZtmou+NTqethjAwnw4Tnw6TuvatwwnwmT R45sZBFUzEci55PXNYxZALIelNdwDfc= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-687-MBVMg84kNVqB83mI-Pw1lQ-1; Tue, 17 Dec 2024 06:56:44 -0500 X-MC-Unique: MBVMg84kNVqB83mI-Pw1lQ-1 X-Mimecast-MFC-AGG-ID: MBVMg84kNVqB83mI-Pw1lQ Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-385dcae001fso2248816f8f.1 for ; Tue, 17 Dec 2024 03:56:44 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1734436603; x=1735041403; h=content-transfer-encoding:in-reply-to:organization:autocrypt:from :content-language: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=4j3RJ6u8WKht0eWYFAXC4mdKyekBt3cyxE0dVaW09rM=; b=h4Z4+akGTd+giHdFh+r6NbwL0P3bcp6yqAXMLl6nWs1T6wkYHdgEhkg2pw8OgbsF0Y h4HyoTaa73fWjfhGT45uwj57JrnTVF2jUbh1OWco3ika69CJQN38zRdyC5CRUXxXC6hM o542ymkUrf4newRKrMMcZxDuceCcrCbacJBLXIJC1L1jj/K2w+U36HQJBFnIHqMc5zcQ zhk9XcY82tD9fEzrM3RGQQ1/sCBni5qoLyFMT5mQnhHrhm0tVvWcaGu5SJBuHwqdG8pf Pw5zpjNunDN/cOOqDV5TtezN/mtmNJ6sOS+qHS+QaEa3PjGjsqd4N+G5PZZ6pjOKOTsD d1fw== X-Gm-Message-State: AOJu0Yw/o0YU7QTt2C5IDMG9Gp5J+e7Uocm9bjuawqHHJ7Avj8ZULrd6 +bvbkGEK1lPI4vF7Wn5xSP9S1QWNWM/NIwHY1KW38MrbPEABleKDCSoWeszoC7z/1NLNI4HJvy9 9vaJlFm28Z8kDZscfp5j+DjtuXEVYpRZuukaZoOE8q+BiIOCb X-Gm-Gg: ASbGncupYJ6ZWAHLQGzD4dZ7fzmiu+Jh16g6zk6wMgl+BGuOK1ntiV4LpP4SI3SRgCz KcjYrDS0v8vQWChOFslO6rjz4B7W2H/jytR54ZmnNJfMtNBZBnO7qHsG1Qe2tgeGqQpQeAT3klV DlPdlaelya78cCSv7w9UZWrISXL3rAoTb8DfizS/ryUezUC7ACBhfte5rGt9t1cpQePEnWeTr5P +USzNOIz81MN2IUhaSjhfcZJ95vopVCl4UiMctb7Mga0mpjUaHLxAy4GYguOsNmF2scphg4vi9h X6REFTZtwo9VOo8= X-Received: by 2002:a05:6000:1fae:b0:385:ed16:c8b with SMTP id ffacd0b85a97d-388da39cd7dmr2484413f8f.23.1734436603661; Tue, 17 Dec 2024 03:56:43 -0800 (PST) X-Google-Smtp-Source: AGHT+IHa6WYqV5Qge4oQqUVyLttlkTx2SZO8PlQZNXX//tdqnqghLk3HOX4fGS672Qzkn0EpanB+qw== X-Received: by 2002:a05:6000:1fae:b0:385:ed16:c8b with SMTP id ffacd0b85a97d-388da39cd7dmr2484393f8f.23.1734436603302; Tue, 17 Dec 2024 03:56:43 -0800 (PST) Received: from ?IPV6:2a09:80c0:192:0:5dac:bf3d:c41:c3e7? ([2a09:80c0:192:0:5dac:bf3d:c41:c3e7]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-388c80121d4sm11215958f8f.2.2024.12.17.03.56.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 17 Dec 2024 03:56:42 -0800 (PST) Message-ID: Date: Tue, 17 Dec 2024 12:56:41 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: hugetlb: independent PMD page table shared count To: Liu Shixin , Andrew Morton , Muchun Song , Kenneth W Chen , Kefeng Wang , Nanyong Sun Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20241214104401.1052550-1-liushixin2@huawei.com> <8e59d2bd-77d3-41bc-83b7-532b018db4e2@redhat.com> <00edd087-8df6-343a-95bf-ca23381085a8@huawei.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: <00edd087-8df6-343a-95bf-ca23381085a8@huawei.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: ODTN9uwajBcH1Dfc4K52HUss7IMlyKqIgJ-UfWnrOJs_1734436604 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: B37242000F X-Stat-Signature: 5w5ckx4fjjhaer6zomcwdyx3d5uihj9a X-Rspam-User: X-HE-Tag: 1734436592-694998 X-HE-Meta: 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 c1iz2NwB 1y8pbS5QTuUy4bpP51CVnAK4BIT1IanwV9T6dQ7YALcSNbT4+D9IB+Uw10AzcMeHFTlnLRjJxpbfD45kIarQb7MAOktQXBsOtWTwm7NU9yTqd4OOk9X9FXTAgq1uypsXvUa+WZaSgykDknmC+hLbhXnDMWm3b+BiEFK9jzq//qknEk4O9QpaU0EHQdf2YhxQzs+5K6UaY0sGOZdq5z+77R4wujS1uY4pkKU6NHYOYGJ1MheVDQf7o2QLZxMMxxSf1Gi0JFV+gtUEOkRDobicXici1eXMqEaay5K6EMOAyNzW5Op0P7rOozSbMgiuv0nlt8QZcVUEUfrjkKN3AlY0YPDtHKQE0AzOv242v5yQnKVh7DabcXMA+j/LivalZ8dzBbR1OnGCQuGKzhD5bIaIM7jh2k+Se7SHI76kOPqkjbxQpSZad0a5U0wk99Ul0+m1lHosvpiExlxLGHWg= X-Bogosity: Ham, tests=bogofilter, spamicity=0.015277, 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 17.12.24 03:02, Liu Shixin wrote: > > > On 2024/12/16 23:34, David Hildenbrand wrote: >> On 14.12.24 11:44, Liu Shixin wrote: >>> The folio refcount may be increased unexpectly through try_get_folio() by >>> caller such as split_huge_pages. In huge_pmd_unshare(), we use refcount to >>> check whether a pmd page table is shared. The check is incorrect if the >>> refcount is increased by the above caller, and this can cause the page >>> table leaked: >> >> Are you sure it is "leaked" ? >> >> I assume what happens is that we end up freeing a page table without calling its constructor. That's why page freeing code complains about "nonzero mapcount" (overlayed by something else). > > 1. The page table itself will be discarded after reporting the "nonzero mapcount". > > 2. The HugeTLB page mapped by the page table miss freeing since we treat the page table as shared > and a shared page table will not be to unmap. Ah, the page table still maps something, that makes sense. So we're leaking that indeed. -- Cheers, David / dhildenb