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 3E4E9C79F99 for ; Mon, 7 Sep 2026 10:42:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 56BCD6B009B; Mon, 7 Sep 2026 06:42:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4CDED6B009E; Mon, 7 Sep 2026 06:42:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3994F6B009F; Mon, 7 Sep 2026 06:42:24 -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 0FDA16B009B for ; Mon, 7 Sep 2026 06:42:24 -0400 (EDT) Received: from smtpin20.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 9C7DBA0E61 for ; Mon, 7 Sep 2026 10:42:23 +0000 (UTC) X-FDA: 85186626966.20.6A82163 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf21.hostedemail.com (Postfix) with ESMTP id E6BA31C0008 for ; Mon, 7 Sep 2026 10:42:21 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="c2/bMEep"; spf=pass (imf21.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=1788777741; 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=bv3lOK+Xa5ryV284dRZSnT9zLzqTU49TaIVbEbCvDks=; b=NVlxTDsgV5jqmcBwR4CrPUZDG1C3ddyHxqR6StgITMPEpvSdlKNx+hb+j9biK10aQKqzZ/ F+FzsSmABxC8dOqSW/ld0Mo7k8lUkvYXfAhB4fOoNIfWzM87VdcbrfTer+sWfLfWjMhcpe vpZ0IiDHq8cexh/xblM+sgH/1dLOWsc= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788777741; b=Dv/GsWnl3VJ+qs4HJLFG7uh6gCs5zD2Lx7C9BFahWDM7RII1hlp7wwhXUcxKac0+yICPGv Vb+9qVmOXDYI1FAl4vJhcjPIYhZ6kG43wCgh8lEUSw1zW71V5Hd5o5Pn7uZ/ribmm1IwwW HnCpnDg2xr0fI3tVwL92UN82uPLDkGs= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="c2/bMEep"; spf=pass (imf21.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 1D15D60AB5; Mon, 7 Sep 2026 10:42:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 336CB1F00A3A; Mon, 7 Sep 2026 10:42:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788777740; bh=bv3lOK+Xa5ryV284dRZSnT9zLzqTU49TaIVbEbCvDks=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=c2/bMEepc1j83amckC2cQIkOIRnCap+Llqh6TjNjeiVKdf7NB9ss/945JvVIokhbb IukLI0/YTu6RxrAhUVpbsG0XjGqmfVLnSWzSDNCoQjgzbk3LsMpl9zTdzw+4NzXv8Q ccoxpfmjtqELVXTvaWf2OqhptHwpy8jH+8FQ0rDoeyqtIGGfme2m0IHdDbfs/r7NJD rIiKgVV6ONvaLTJyzd1dDWerZbKiB502T5UkKY2bwWEoPDFjH8KpmECFKN6E6E9iEe KnAQSTUhY4Zmjpi48FUyoqVRESlKYxNM5ub1HmHySmcceSCH2Ia8m7Gtxg7DnfI5Uc Cz749Db8BmCcw== Message-ID: <616f0e6b-178c-4b50-b759-ccb20d9db9f4@kernel.org> Date: Mon, 7 Sep 2026 12:42:12 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] mm: thp: restore SHRINKER_NONSLAB on the deferred split shrinker To: Qinyun Tan , Andrew Morton Cc: =?UTF-8?Q?Michal_Koutn=C3=BD?= , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R . Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Johannes Weiner , Yosry Ahmed , Nhat Pham , Chengming Zhou , Kairui Song , Shakeel Butt , Xunlei Pang , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260904033503.4067283-1-qinyuntan@linux.alibaba.com> <20260904033503.4067283-2-qinyuntan@linux.alibaba.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: <20260904033503.4067283-2-qinyuntan@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Stat-Signature: njc55s4fizg563ftqz5dg8uitirjnh35 X-Rspamd-Queue-Id: E6BA31C0008 X-Rspamd-Server: rspam02 X-Rspam-User: X-HE-Tag: 1788777741-924021 X-HE-Meta: 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 662Is4GV 9RkYA/ajXFsLYeWRa4dyHC4bfgZ0bzsQ7tX3zfyDB25zhU/pMnufuGW/2QzyMhBYqVQAasLQnRUvlBAnBlxrjnDpyBtU240y9L/ygoyQyDNT0W7/arLS+QsOpyz37dpkJMDnF4uTdrRDu3OTlwSf9F9r+NCXKz/K53MsyKqFt7GaE++HQ/Mo0lW1TXJP17WZMDNO9UMud6zqrDkbHEidebph1zKiK0DCYltN/RKBAJ/Wpqp772wK0rFO/iEnwF54b3UeqQp1zh7tTKUHpn0bokNK7RXhbCd2KE4p7VzFX3fS0laofJEuLqAdOpLc9EvPgzOnDsbkN9KeFGVNPsCvjG2lIsYUiFB6hlB6VZ7Br/wyeXDV/tflX+Y3PWJQ0+TY6PsgtjzwO/4zpsst2F2q3RlxmCDeBCWnXsRX2d2jYTg2/3wQ0Dq1FME1LDA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/4/26 05:35, Qinyun Tan wrote: > On a system booted with cgroup.memory=nokmem, the deferred split > shrinker is quietly demoted to a non-memcg-aware one. As a result, > partially unmapped THPs are only split under global reclaim; memcg > (limit-induced) reclaim never splits them, so a cgroup under memory > pressure keeps its underused THPs intact. > > This is a regression from commit fafaeceb89a5 ("mm: switch deferred > split shrinker to list_lru"), which re-registered the shrinker without > SHRINKER_NONSLAB. The shrinker had carried this flag since commit > 0a432dcbeb32 ("mm: shrinker: make shrinker not depend on memcg kmem") > precisely so it would keep working with kmem accounting disabled. > Without the flag, shrinker_memcg_alloc() fails with -ENOSYS under > nokmem and the shrinker loses its memcg awareness. > > This was noticed by Michal during review of the patch "mm/list_lru: > don't copy stale shrinker id from non-memcg-aware shrinkers" [1]. > > Restore the flag. > > [1] https://lore.kernel.org/lkml/697713c4-0857-485b-aba7-c74f37a3c8b4@linux.alibaba.com/ > > Fixes: fafaeceb89a5 ("mm: switch deferred split shrinker to list_lru") > Suggested-by: Michal Koutný > Signed-off-by: Qinyun Tan > --- Acked-by: David Hildenbrand (Arm) -- Cheers, David