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 415ECD68BDD for ; Thu, 18 Dec 2025 07:09:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8C27A6B0088; Thu, 18 Dec 2025 02:09:24 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 870686B0089; Thu, 18 Dec 2025 02:09:24 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 752526B008A; Thu, 18 Dec 2025 02:09:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 662066B0088 for ; Thu, 18 Dec 2025 02:09:24 -0500 (EST) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 1FAB76085D for ; Thu, 18 Dec 2025 07:09:24 +0000 (UTC) X-FDA: 84231715848.25.E304D8D Received: from out-189.mta1.migadu.com (out-189.mta1.migadu.com [95.215.58.189]) by imf08.hostedemail.com (Postfix) with ESMTP id 3D19A16000D for ; Thu, 18 Dec 2025 07:09:21 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=wo9TLXqB; spf=pass (imf08.hostedemail.com: domain of qi.zheng@linux.dev designates 95.215.58.189 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1766041762; 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=BUoGWDo/ueOcvU1k8f5hEcEJi1kwbtQAhA8TscsLJ8c=; b=oYScDaan3OWri467dsG0l+PwFZdeaCQ4xqVC/siRUC2MjoX1FHC1zqb2bqlV4+DN/Mm4GO 68bU3cwmx2EJUlvKMSVISnGcIjuJ486J/ZXA7eXEodP2LHcVL2bYufcY/Oga8CTYYeTxog yZbAOPyKZY2CRYiPJNPFUDO1564nXis= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=wo9TLXqB; spf=pass (imf08.hostedemail.com: domain of qi.zheng@linux.dev designates 95.215.58.189 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1766041762; a=rsa-sha256; cv=none; b=CLP9lcOaW7v8QRoGInxGBLkjytdoxFrmzO5OY7uIqO0tILvDZYvzeFnzuS4ZZ6S8abCVXx evT1QjyKMkizmCcHv+26HNHsh3LHhQqvc1V/WKY4Q9i+AgCAmbErw8sO+5YUhEmcISbEcT /9cCPVKtL7kJ4ggku6NnOPxWn7RYbKY= Message-ID: <8aee44f5-11ec-410a-9b45-5cb224e9e23a@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1766041759; 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; bh=BUoGWDo/ueOcvU1k8f5hEcEJi1kwbtQAhA8TscsLJ8c=; b=wo9TLXqBZg4c+msgguYsic0XAZGdytn6yFZ3/W45uO5LfEOX9QMvyNr5REVy1yBgtjP/GH KNsaOWX0RZJDlSuKh7JM+rbcn9obJMFT8Byxvn/J43GwgGJDRn1eZ2CI7aI+UG1NgTiIpW LiEqHefQt8UMdpFjTS+Z4nlZuU6nv6c= Date: Thu, 18 Dec 2025 15:09:04 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v2 20/28] mm: zswap: prevent lruvec release in zswap_folio_swapin() To: Johannes Weiner Cc: hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@kernel.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, chenridong@huaweicloud.com, mkoutny@suse.com, akpm@linux-foundation.org, hamzamahfooz@linux.microsoft.com, apais@linux.microsoft.com, lance.yang@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Nhat Pham , Chengming Zhou , Qi Zheng References: X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Qi Zheng In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 3D19A16000D X-Stat-Signature: ujpqu8jwrykkixfrtymjhsk8pf1ztxdj X-HE-Tag: 1766041761-309656 X-HE-Meta: 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 yndUYaeg 2U5dV1Wop8tdbRp+lA2g7RgAbeTz42sbuDP/+Tn7FNc4RU/vz6FnGbJMq2dkhragJNmJ39QIyezy66kxDFAY+sUDjY6+SKgJ2mB6VcgjZAwKMKnCBBvi66PKnnkM1FXOf46eH6D4EYr0Hm4LjSMz+IKgd+1tOQDI8c5NPKEGFTFeWAHBb26NTheZzYT7fhruNcbmBXuwONyDFBlIdYQ8JD4RMWqmUQo+GHwKvyHITHVlThPuxo6HbdFFISQ2ZttqL+ZjrQUSAAcSbT/LnmydqczZzvq37ZvURPxniytvG4XctjHX3Y3/mgt24RkgEGXITIqjDQ04GOWV2pgRdWBhQGHx8IjEOy801Qie/odLwqr2PU5KJbNnCxtk7ue0bYTNPlHSQ 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 12/18/25 6:33 AM, Johannes Weiner wrote: > On Wed, Dec 17, 2025 at 03:27:44PM +0800, Qi Zheng wrote: >> From: Muchun Song >> >> In the near future, a folio will no longer pin its corresponding >> memory cgroup. So an lruvec returned by folio_lruvec() could be >> released without the rcu read lock or a reference to its memory >> cgroup. >> >> In the current patch, the rcu read lock is employed to safeguard >> against the release of the lruvec in zswap_folio_swapin(). >> >> This serves as a preparatory measure for the reparenting of the >> LRU pages. >> >> Signed-off-by: Muchun Song >> Acked-by: Nhat Pham >> Reviewed-by: Chengming Zhou >> Signed-off-by: Qi Zheng >> Reviewed-by: Harry Yoo > > Acked-by: Johannes Weiner Thanks! > > Btw, it would make the series shorter if you combined the changes to > workingset.c, zswap.c etc. It should still be easy to review as long > as you just stick to making folio_memcg(), folio_lruvec() calls safe. I prefer to separate them. For example, as you pointed out, in some places, it would be more appropriate to switch to use get_mem_cgroup_from_folio() to handle it. Separating them also makes subsequent updates and iterations easier.