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 655D5CA0FED for ; Tue, 9 Sep 2025 15:19:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C7BD88E000E; Tue, 9 Sep 2025 11:19:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C53AB8E0003; Tue, 9 Sep 2025 11:19:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B69958E000E; Tue, 9 Sep 2025 11:19:52 -0400 (EDT) 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 A56C28E0003 for ; Tue, 9 Sep 2025 11:19:52 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 96A5C86A92 for ; Tue, 9 Sep 2025 15:19:50 +0000 (UTC) X-FDA: 83870071740.08.7E925B1 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf23.hostedemail.com (Postfix) with ESMTP id 4CA6E140004 for ; Tue, 9 Sep 2025 15:19:48 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=AdDzvrBn; spf=pass (imf23.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1757431188; 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=InYbqwt9glvNL4C3LVQbjDo/hY87wVdMa3rsXOKx3FQ=; b=4vIK/I9iItjVTlQHgjF0wQiJAbH8eDa6PBKctQxkLHBn2Cq3XtCzqrYiiwJl4DJwh1mmC6 4gJZLgZ6TPMJm3VP7HFNadi4OCDurUnuPkuZVRVUYrlINDS4+VOaF7AOqwEVX7bpFuDKdq sY2ZqERt606YlRSZYZLLkFJSpkgkwtE= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=AdDzvrBn; spf=pass (imf23.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1757431188; a=rsa-sha256; cv=none; b=B7nanVMK1/TeiazKXN4M5xsePzGmYr5VHxVGjUHakaEd2TIlBr73FfJTFcK/UzfX63dkbV 3ZDk7enpGnV/zPuYB1Y8UlazkKy08BeNijauqVj4jB79ncmqj75OjMdnUcnZ+si1i27kgM ImFagvk9euaIUkvw1m8bKphHtHrKxiM= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1757431187; 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=InYbqwt9glvNL4C3LVQbjDo/hY87wVdMa3rsXOKx3FQ=; b=AdDzvrBnFpIJgOgR6Li+L0FWpbCNSfsA9C2Bamwj+3jYNh8jIG5bcSmtzw5XKRXnVc1mLg +X3Vmd2gZpQFjh97ovKVBsbPFp9nQp/FBYJn1qgfFfB48GCjIIDF2s3BhrMOGKaOnnukQa sKzMm30cSpDi/S9I82NZwoKcktnkDCM= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-659-iBcgtq6wN5WYJJjxvxRzag-1; Tue, 09 Sep 2025 11:19:46 -0400 X-MC-Unique: iBcgtq6wN5WYJJjxvxRzag-1 X-Mimecast-MFC-AGG-ID: iBcgtq6wN5WYJJjxvxRzag_1757431185 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-45b467f5173so40959185e9.3 for ; Tue, 09 Sep 2025 08:19:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757431185; x=1758035985; h=content-transfer-encoding:in-reply-to: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=InYbqwt9glvNL4C3LVQbjDo/hY87wVdMa3rsXOKx3FQ=; b=F1sxBFSkGk8BNHvJbiTXt02u0Rj7w/S/MTtFIBu0VIG+lFDD2ldDrENkv5h92Bqd2p kTIqIqq/CM8DMgitWqyeccAno8Irs3lv5LeOH0Uxbt0gmJOwzLn6LEdpcCrj0q9HBFn3 AZ8zjawkkllP9diDReUI+ziXj6TsyXh6G+RrSkjVwFZ7r/BooLRReLqRa0nddcNnykJv Domi6ILOd3LJSF0y2jfvP4LEXl2esm0SoWQIAhrPjw8D3VcnbPLaHWjOhcf4sQd4hhyy 3/NsdF1RK9sLeHcpjuSEUgByqsqmyo4+bY5ffYKjHj4hPMfSQm0Qa/N73sRyC/KVPSKc 9d+w== X-Gm-Message-State: AOJu0Yz5dMnNEEmKY8afkBIJNKboTJiCSVvTYzeyIPM+db7USFlxAUuF yS8Tpzk1thMp4fLS1aRcFdUwk0pQt1YkyM3aXKca2cvvn7raw1vwV2Kwuzq1767sINUZrUhDYJq EM+RoVoRGmre9TKY7WIauAwx729x33HFsryLTIObNbNmsxwlB+4YE X-Gm-Gg: ASbGncuSIpGU3va4OiTcuXoB6SveeauzRqIGc0/g8ANi9ppuYkAN1ocO7/yLEYeg3fh p0ritdNHiR+KMvfVFDj/7CZvoXvZOSwC1BfQTbGlLDTkYpHMKGGkKpT5wHUA9iI5WA1PDakdF8G syOEM0UJoJN4pIvDStElwlIVqipvVKNfMnu1XRK4l87wQChi+N95zX0EKYLZ2kljOHUjmY2aBEW HBfVsp5JQhZ33CvPQdbXGKHMR1UVGYK+hORJnwALrDbqLuQt8XtrXtVnvdOuPx/Ib/rNMH4swO1 cks9TfMcVORK75K/fiJOBCJzQvOInsLHxTrOy8xgs4dLPOZsGYJxiNq4t2K4SSW1ze3nbRtwvtk WnLAkcvY+6qp2mFjdnFDOHbYsIcWXTv8TBabht1et41XIQ6pS6AR8cy72sSccCcbOr54= X-Received: by 2002:a05:600c:4694:b0:45d:d908:dc02 with SMTP id 5b1f17b1804b1-45ddded9c21mr103637065e9.31.1757431184840; Tue, 09 Sep 2025 08:19:44 -0700 (PDT) X-Google-Smtp-Source: AGHT+IF1bljri4jY2JSQWXumU2Cl1Vy0YyVDFF7sGRN7NXMVP/WZtzyUJBsPOarkJX8Q2cJU6IwvCA== X-Received: by 2002:a05:600c:4694:b0:45d:d908:dc02 with SMTP id 5b1f17b1804b1-45ddded9c21mr103635995e9.31.1757431182935; Tue, 09 Sep 2025 08:19:42 -0700 (PDT) Received: from ?IPV6:2003:d8:2f23:9c00:d1f6:f7fe:8f14:7e34? (p200300d82f239c00d1f6f7fe8f147e34.dip0.t-ipconnect.de. [2003:d8:2f23:9c00:d1f6:f7fe:8f14:7e34]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3e7521bfd8csm3255178f8f.11.2025.09.09.08.19.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 09 Sep 2025 08:19:42 -0700 (PDT) Message-ID: <283fc6d5-caca-4a67-916e-55246a5a4cbb@redhat.com> Date: Tue, 9 Sep 2025 17:19:41 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 05/15] mm, swap: always lock and check the swap cache folio before use To: Kairui Song Cc: linux-mm@kvack.org, Andrew Morton , Matthew Wilcox , Hugh Dickins , Chris Li , Barry Song , Baoquan He , Nhat Pham , Kemeng Shi , Baolin Wang , Ying Huang , Johannes Weiner , Yosry Ahmed , Lorenzo Stoakes , Zi Yan , linux-kernel@vger.kernel.org References: <20250905191357.78298-1-ryncsn@gmail.com> <20250905191357.78298-6-ryncsn@gmail.com> <0bbda135-068a-45bd-afd6-3f5cdf4e570d@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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+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: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: sCVLbxG9U3p4G-Av4ojm-6EXNgJQucrEnHb5W8l0rIY_1757431185 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 4CA6E140004 X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: n8fdu71xxqskea4pqcx7jwx3thnjpff9 X-HE-Tag: 1757431188-726887 X-HE-Meta: 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 iBjc8xsi pi3AuYKQz7zyh55IhFm5VnETgG7Q+W7Y+4BDngzjkUtKvABZnePdUobBr+L8MPd1KP3iJY6wwVy361ob9XLkuWCH8ukPy+DlKQjjdB6jf4/A9kUJ5kWL3uAB27p9t4orU+JiSy41kDsSwv/o3D+FGbYzsJMe840zkhVw3uHTx+GfYASdCAjG41Euuy9mpmb1qJ0Zdm/7dHoY1+wnw/3xGm5+0aGlGGrAAOyCgo7ClzjopSbgIEf203rvPpLxmfFPWkyVrmhHw4Qrit0OcBB7nxQoqGdv4i5e9anpN0ARW6Oig6EGmqJ7x11pa5ZsFtfZChPMxHBva/IB2B+1HJgkMO2avykMXepF7rwHlsXoTNf5lEUPdqYeLyvAeWWwjYs5m8JPuxAN59o9tLR0E7CJxV8cEuW+169uFQud7mX7q5JfHL3IYgNUB+lKdnhCzz7K8dzjX01hJcay8KoxqjVNgK9w+YFr7Q5OAb0ZHTh+jTCryeF4= 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 09.09.25 16:58, Kairui Song wrote: > On Mon, Sep 8, 2025 at 10:08 PM David Hildenbrand wrote: >> >> >>> >>> folio_lock(folio); >>> + if (!folio_matches_swap_entry(folio, entry)) { >>> + folio_unlock(folio); >>> + folio_put(folio); >>> + continue; >>> + } >>> + >> >> I wonder if we should put that into unuse_pte() instead. It checks for >> other types of races (like the page table entry getting modified) already. > > Doing this earlier here might help to avoid the folio_wait_writeback > below? Why would we care about optimizing that out in that corner case? And checking the folio right after locking seems to follow the > convention more strictly. I'd just slap it into unuse_pte() where you can return immediately and we don't need another duplicated folio_unlock(folio); folio_put(folio); continue; -- Cheers David / dhildenb