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 31D66C79F9E for ; Mon, 7 Sep 2026 07:11:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2AA8C6B00A2; Mon, 7 Sep 2026 03:11:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 281DC6B00A3; Mon, 7 Sep 2026 03:11:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 198286B00A4; Mon, 7 Sep 2026 03:11:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id ED2086B00A2 for ; Mon, 7 Sep 2026 03:11:07 -0400 (EDT) Received: from smtpin26.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 80AF3C0683 for ; Mon, 7 Sep 2026 07:11:07 +0000 (UTC) X-FDA: 85186094574.26.433B610 Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) by imf03.hostedemail.com (Postfix) with ESMTP id 47FE420009 for ; Mon, 7 Sep 2026 07:11:02 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=myjIoRI1; spf=pass (imf03.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.130 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com; dmarc=pass (policy=none) header.from=linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788765065; 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=8NYiIdoA0clTQtdI5G5CycyM+YaApfB4aFiNuht58Cs=; b=dGAzz2RxSwXC0M/iXkgbsLR1gv3LpMZzC6e4G4x581jO36216REqXI3X4B51CCAHxKu5Cs 4eUyhO8z2mG9Dw9zhdPC8VM7NKZy14EU090onVpF9pk7a3k/JiSP56hdHwd0fCGY0yOoZ/ zhLpQxRUr4rX//H4zy3AMMRZZHErvUE= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788765065; b=StxCs77fFcL2GSsSmyUJIGrmzNe5jI5FvjJbF8d52LdPddQlxlm3k0E/H2B6HZuiD105Sv zBdWquJ55Y5MjO3Af1YU/uHT8xznwBqkL3s08AIs7ObI9APmy7cOMf043vXmk4Ivj+9W8Q R0dcZpijObK3jQPyGbvUMaJFguRaoHA= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=myjIoRI1; spf=pass (imf03.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.130 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com; dmarc=pass (policy=none) header.from=linux.alibaba.com DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1788765057; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=8NYiIdoA0clTQtdI5G5CycyM+YaApfB4aFiNuht58Cs=; b=myjIoRI1mh/KNXuOlUnOF1hTMQA4Ey1eosSFYCrX/fnXjR+la1ZKOwkItyUXyf81VP34m+j3yTlVcOIi4ciIXCqZ/Qn1VXN8fYtfJgbY0p+TJFMrGdRwW+rXdkMsYnX9WEupr9yC1GAQciMyV83UaKgr1wS741hR7948/NtdIBI= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R421e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam011083073210;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=22;SR=0;TI=SMTPD_---0XAQvWM0_1788765054; Received: from 30.74.144.134(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0XAQvWM0_1788765054 cluster:ay36) by smtp.aliyun-inc.com; Mon, 07 Sep 2026 15:10:55 +0800 Message-ID: <78b338da-d700-4457-aab4-8b051343c981@linux.alibaba.com> Date: Mon, 7 Sep 2026 15:10:53 +0800 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?= , David Hildenbrand , Lorenzo Stoakes , Zi Yan , "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: Baolin Wang In-Reply-To: <20260904033503.4067283-2-qinyuntan@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 47FE420009 X-Stat-Signature: otys9u83iuua7sujcz7juyt7xmm4g7rd X-HE-Tag: 1788765062-126862 X-HE-Meta: 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 QRBvg2GW ycGuX+OiLoJZagUyV/0SHtDpBsENGFbxl9cvq5XPN2DqtO14spSf+22IOOViNUtuXNM5JKt37bk8Cea0lwlZzj4aiaAi9FDxMQ3yR/X36H6vJEe/0KXXuDauD5ppZEp4rQy/TIU8pDhnPyVH5rceMaPCrK8L3MJhyo4/9v5vYn1dvjEc9xru+eFeEXVXOVGo8b8B8wcSAMQNi849kBFAFoOL6KQJcBZ0BSt9byLbCc4TPrevD/D19O+djOBz+KSMSyVkUlBVgStGWU5eMdbHMa8iitNbQ5l1goX8huH568VrcMgV2kYbGn1oKWEyL1yd8QJH0LRPPhZD56NRONq7vkiXqGEy0rJYpm2Pf89HSdeQRpNgVlpS7IL5vIH6IxCnriMnvE/N8jZ8qwdmVr2xeM5vVBDeMbdVRDe6YC0WWhUYD9jby/AJBYM166SaJ83jhX3cXdLnR/NT3pUI= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/4/26 11:35 AM, 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 > --- LGTM. Reviewed-by: Baolin Wang