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 06636C79F82 for ; Tue, 8 Sep 2026 14:12:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0912A6B0093; Tue, 8 Sep 2026 10:12:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 041EC6B009D; Tue, 8 Sep 2026 10:12:34 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E99846B009E; Tue, 8 Sep 2026 10:12:34 -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 C20146B0093 for ; Tue, 8 Sep 2026 10:12:34 -0400 (EDT) Received: from smtpin25.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 6028B406DA for ; Tue, 8 Sep 2026 14:12:34 +0000 (UTC) X-FDA: 85190785428.25.582677A Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf03.hostedemail.com (Postfix) with ESMTP id 9A3842000B for ; Tue, 8 Sep 2026 14:12:32 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=Q6F5C9hk; spf=pass (imf03.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788876752; 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=Y7QY+32xJuMq6Tz60T2FtAYLMwPxmKJa9EIw0naxNRw=; b=IMsOro+mfd9wTCKaipr+G6c0PWBK+hJ7xwms6jCnI1yXzLsCwJVXS79heYf9HRFlmUR1rh 4uC/ttgiY7i1yf/hxQOA6Grpb98dz5FP/RB0asbDI8+oeUYXeNlGjvmWQ/4vQSCSDzboRJ zBnL4cGJI3AlU4C24sivWW+TUX0ybE0= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788876752; b=eb1T6lsjrfIF5nXABCDZhGDipGjWlqTrqck8YXD5EWr8VC4h/0NrdNxtpi6IFuqO7cGn5p hD0HWAVGgmyaTiH91+jEDurBXqEjfxiJ77/egVjX3JKx57baIBwnP+7hV6eCjES/Jv2iP0 4Zn3h58m4X7b1oZ3sabul8mwlCk6TkU= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=Q6F5C9hk; spf=pass (imf03.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 1963E601F7; Tue, 8 Sep 2026 14:12:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 019B21F00A3A; Tue, 8 Sep 2026 14:12:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788876751; bh=Y7QY+32xJuMq6Tz60T2FtAYLMwPxmKJa9EIw0naxNRw=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=Q6F5C9hkksHR3U/qP+t0jNS27VaZxxFP2ctszQifVzprISbqSQo7LQFXLrJFnIX1o Bafps7WKNOyAbhevxCim2zGutTnUOIDSifFGUGCiP9RwxASEYTPSF2tXGt+5AFtsRQ bRbuIfuVAYhAwBPbxXaTWAqOrlN/JwyhCpmyzSJuqnWuXNvEK6V0gdeOkP6z1D5xpg z5EMDrurGFQ3/kil1agUJxZyQJZ/6xB3Zotk2rMQmqW2hPUL8lXvudBSa0NDHTmxQ1 K84k8y8+PPNx8ZBj80Ht1qxr0ljuwdeEVDsbdZElRqKWewvLo+314UzApBhluK51Mx O5trPvNcY9YMg== Message-ID: <9bc5787d-6106-4d0f-816e-cdf5a308abd6@kernel.org> Date: Tue, 8 Sep 2026 16:12:23 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/3] mm: support splitting mappingless swapcache folios To: Kairui Song , Zi Yan Cc: Shivam Kalra , Kairui Song , Andrew Morton , Lorenzo Stoakes , Baolin Wang , "Liam R. Howlett" , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Nico Pache , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20260805-b4-mappingless-swapcache-v1-0-b1d78ba257ca@zohomail.in> <590B3189-5B66-4ECB-84CD-7B7EF18C0E54@nvidia.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: rspam04 X-Rspam-User: X-Stat-Signature: 6ebjt8mx7t49tdteyy5ddrb947m1aiw9 X-Rspamd-Queue-Id: 9A3842000B X-HE-Tag: 1788876752-828783 X-HE-Meta: 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 gODCLSTW 9ULFDLEoFMyKXwf4i8HCX9NV4D4CbVJRmnAkQtL7vgXJxS3qk0D1dTziZWvX/7GfvpoZNN4c+a9qPpK0uQzoJa0CtXId8K3SM8Le+82hH9aDAEM/R2FoUCArmjEnq4PGQy1fVyz/8HMRDwIlgosoRwc6j7F9l1QB8vSxalAAX5bBDdWjvN8sBZV9drbb1rkIhUjAB3316eQGbGEKsHCSQMIdrBLA930CHZ/OEZgAkZMoVjYLK8CcNR/LpdpEK/6wc+iZt Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/7/26 23:22, Kairui Song wrote: > On Fri, Aug 07, 2026 at 10:18:05AM +0800, Zi Yan wrote: >> On Wed Aug 5, 2026 at 11:54 AM EDT, Kairui Song wrote: >>> >>> Thanks for the CC, this is actually not hard to implement as shown by >>> Shivam, I just found the code more and more hard to follow and fragile >>> as we add more logic to it. And we don't have to reject higher order >>> split either which can be seen easily if the code is cleaner. >>> >>> Personally I think doing some cleanup first is better, I haven't post any >>> code as right now there doesn't seem to be much user of this. It will be >>> needed if more clean THP swapcache begin to show up due to things like >>> THP readahead for swap, which isn't here yet. I think I can send an RFC >>> tomorrow just for reference. I'm fine if we prefer to remove that TODO >>> using this smaller change first :) >> >> Thanks. Can you also help review this patchset? The changes looks good >> to me but I am not sure if I get all the details about swapcache handling. >> >> -- >> Best Regards, >> Yan, Zi > > Hello, > > Thanks for the reminder, I got a bit busy so delayed for a day on that > RFC. > > For this series I think it's functionally fine, just the split logic is > a bit complex to follow and we still have restriction on swap cache > for order 0 uniform split only. I'll have a closer look later. Also > let me know how you think about that RFC. How does this patch set relate to your split cleanups? Is it still applicable independently? -- Cheers, David