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 B27D5C79F9E for ; Mon, 7 Sep 2026 12:36:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id AFDBC6B00A0; Mon, 7 Sep 2026 08:36:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AAEE76B00A1; Mon, 7 Sep 2026 08:36:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9C46A6B00A2; Mon, 7 Sep 2026 08:36:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 727236B00A0 for ; Mon, 7 Sep 2026 08:36:47 -0400 (EDT) Received: from smtpin17.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 070874014B for ; Mon, 7 Sep 2026 12:36:47 +0000 (UTC) X-FDA: 85186915254.17.D5DCA1C Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf05.hostedemail.com (Postfix) with ESMTP id 54077100003 for ; Mon, 7 Sep 2026 12:36:45 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=oCmkiCjG; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf05.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788784605; 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=NiAfvUfU16Fbk/i6m8tmsKk9M6uO5GP022sgVAPPefA=; b=1oVzvrNbvWaeacXkTKX1Ehi83tfkxBK/+ilsbBu6kla6udBItmvPNzXvjson4dGxSLaLlx bDb8WzVuPka3XrqAiW13W35/3k356g5dPl8tS5wusFuOIRg2915F5oV3ruehWzInoqPBrm nsPDhjZuOdvVDfVm9uh6BMpNIkSGhPA= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=oCmkiCjG; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf05.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788784605; b=8PpmoQqBdyINWXTJnNFv1uSp/NjjJjoAPcU2KLRCJOy0Wumzf2Zzdy1bafyfdZfapUtG+i qaWcXuXuXVMhzwjeFLW8OwgYdx2tDO++r2tPpSnyMwze4uuc9+RUra05+TU64DpE9F4FNE O5OizhcWDKRy9SEyhWgKh6yg6llziGA= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 6BADD601F9; Mon, 7 Sep 2026 12:36:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F2ED1F00A3A; Mon, 7 Sep 2026 12:36:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788784604; bh=NiAfvUfU16Fbk/i6m8tmsKk9M6uO5GP022sgVAPPefA=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=oCmkiCjGU2CzuKmMRmxVdk2YPKXOh7BCzakTnHcrwrmNMIA57A14Z+iJJy/7rw6AI lcS3X6cWk3xhYkfT9k3yWTMd6RyC2t6wVdQvSVs0f4uzcERZmptdtUaaedlgrNDKtJ I/ijEZiV9jJruxmgPfYEwfFEOfuZLSif9+Ky1LNvzaLpFDUoqPXulExLJMB8PeWNwZ zgSnmNNSBjGOnjMRYLiadlvxZBGD/UaaIW3XQoxJGMEO7NS++3maj5EngPLv1Donsw V4c9YRRekgmQA5zdqSHxRxmGVad8RRrixthi4L6AFd6XAOswPHhzBLNvCD//Mz9kS2 jfupjHBbpRS0g== Message-ID: <6e85fde9-9314-4854-99fb-3582b13486fd@kernel.org> Date: Mon, 7 Sep 2026 14:36:36 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 09/18] mm/huge_memory: move anon_vma and filemap management into split helpers To: Kairui Song Cc: kasong@tencent.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Chris Li , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Youngjun Park , Shivam Kalra References: <20260821-swap-thp-cleanup-v3-0-9b43f5163238@tencent.com> <20260821-swap-thp-cleanup-v3-9-9b43f5163238@tencent.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 54077100003 X-Stat-Signature: 8wmirmdwtu7npmipqox7x4e9jxiuednd X-Rspam-User: X-HE-Tag: 1788784605-219887 X-HE-Meta: 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 HDqxsn/O TzAABos3jzaZqhQ7Wt8QbH/naW4GGVdBO0gPz5S2cQdHCeNcQPsEltPO9HVDt4IY6Jc4P3FLFS87SrjlFzwROfskZjKjSMi40YO9zQKUer5L2Hy87KaxE2ANmQfHwjkotMHF3YxPk9uCMaV+Nn9+PK3x1cdYrAZzFt48stEuVTfcsyOjnutJA/Q+SqBYO/4FVjBDlZyogVSM0L5IOdk+1wMHLbnD5lawghqNbezzZnUg+5c9aJUbHTH2lVcETbrX3DntECjU4UKTv640UqZQNDqTSgmoSjykEM/7xS0Kqi8DAtTaYzZm9B+miflQDaDFnwsmrZ0vtHshHhqk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/30/26 17:23, Kairui Song wrote: > On Thu, Aug 27, 2026 at 06:36:18PM +0800, David Hildenbrand (Arm) wrote: >> On 8/20/26 20:55, Kairui Song via B4 Relay wrote: >>> From: Kairui Song >>> >>> Only anon split needs vma info, and only file split needs the filemap >>> handling. Move the related code into separate helpers so they are >>> genuinely more self-contained. >> >> This patch seems to do more than that, like relocating the >> folio_expected_ref_count check (and duplicating it, which is not so nice). > > We can keep it where it is right now, but this patch is moving the > anon_vma_lock_write and i_mmap_lock_read into the two anon / file > helpers seperately, so keeping the folio_expected_ref_count check > outside and before the helper call will cause a potential higher > false positive / negative rate of this check? Leads to unnecessary > call to unmap_folio. > > How about moving the folio_expected_ref_count check into > unmap_folio since the purpose of the ref check is to avoid > unnecessary unmap? No more duplication that way. I think the crucial part (for anon folios) is to also check after we unmapped. See __folio_migrate_mapping(), where we don't do the !folio_ref_freeze() in case we tun into the !mapping scenario. -- Cheers, David