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 EEFE1D64085 for ; Wed, 17 Dec 2025 07:32:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 60BD86B0096; Wed, 17 Dec 2025 02:32:54 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5B5CB6B009D; Wed, 17 Dec 2025 02:32:54 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4DCB16B00AF; Wed, 17 Dec 2025 02:32:54 -0500 (EST) 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 3FCAC6B0096 for ; Wed, 17 Dec 2025 02:32:54 -0500 (EST) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id F3E00BBC20 for ; Wed, 17 Dec 2025 07:32:53 +0000 (UTC) X-FDA: 84228146226.18.112BC4D Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) by imf16.hostedemail.com (Postfix) with ESMTP id 2119F180014 for ; Wed, 17 Dec 2025 07:32:51 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=utjimqar; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf16.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.182 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1765956772; a=rsa-sha256; cv=none; b=aibOSXTYoOcu4ehn1LYbtLfTTnJyxkDgz8LNWtnbCG/vnQPBzBSotCCc7fpze/+GMdFAUG WtNs32dx/91UrDSgu8lDLFHZyktiq8ouN5l2y4lHQqESJYPbdk+b9vINnhAj/Y0Nf9qgLJ EV70dJtuDJ/aF7yQ8/ehywmg8Nt9K+E= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=utjimqar; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf16.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.182 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1765956772; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=r7R2YsecSy/bMyWfSR2fXTDFkSfi8ZmuktkAOmJUkaM=; b=caitP/bwyjgPLFs9NI1UCpB/dc2GRqqo+L/5LlCtOnygYoxdtoMisawdPhqk7zGb75uam9 gVcxR3Yu+qDUVr26FQ8Fd+oyLu/RWBZt6fDgAqrzXR4QtdA2QyY8i8QMs7nZTsBUptSd4P VrJvwYhe19ogZdda7tFEWNvgIaQ2eF8= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1765956765; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=r7R2YsecSy/bMyWfSR2fXTDFkSfi8ZmuktkAOmJUkaM=; b=utjimqarpJXzPTVvhid+eE3cwOsJ/hVXX6Fz447+S0Nrj5Mhr4vYtYMabOisntRkuyl9gg MQYGXnv6tjh2xy/Ve9Lmnbfr5XyjYeZXIoIuOKmxsE5zZxZmcG1tdfavDUQWt8ksYgQ4hQ Asqcc8Q9449fvBZaJ9EYLaptzYLE8rs= From: Qi Zheng To: hannes@cmpxchg.org, 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 Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH v2 19/28] mm: workingset: prevent lruvec release in workingset_refault() Date: Wed, 17 Dec 2025 15:27:43 +0800 Message-ID: <1b6ad26b5199b8134de37506b669ad4e3c0b6356.1765956026.git.zhengqi.arch@bytedance.com> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 2119F180014 X-Stat-Signature: 5eukjawz1xnqcnoc6r4g6xxr7qkcj366 X-HE-Tag: 1765956771-27459 X-HE-Meta: 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 bTHXSsgF xkv0IE/1/z6iHkz9ceETNhg1vhPkZlwKYlxGoCs/7k6GBPcxGeYS9qwmTq6rsFeYy5SAw8OfCJJbxbQ5x5oAec/WVcfBjpyyjLCKKNA2k8yKh3g7+3MyNlCiwf6xuXGZsNSw/Mzanyau2O4c6U1OZmbLh4Ran4lVbFMN6U4ocHOoo8oNjvJARuyaoIhWesEn8CgCeESLkhVJInhPyaRoiDcl+r4xnYrs/eT+BMTSXHEIK7uAQSZxpIX9A35qWBmaKsSzR 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: 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 workingset_refault(). This serves as a preparatory measure for the reparenting of the LRU pages. Signed-off-by: Muchun Song Signed-off-by: Qi Zheng Reviewed-by: Harry Yoo --- mm/workingset.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/workingset.c b/mm/workingset.c index 445fc634196d8..427ca1a5625e8 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -560,11 +560,12 @@ void workingset_refault(struct folio *folio, void *shadow) * locked to guarantee folio_memcg() stability throughout. */ nr = folio_nr_pages(folio); + rcu_read_lock(); lruvec = folio_lruvec(folio); mod_lruvec_state(lruvec, WORKINGSET_REFAULT_BASE + file, nr); if (!workingset_test_recent(shadow, file, &workingset, true)) - return; + goto out; folio_set_active(folio); workingset_age_nonresident(lruvec, nr); @@ -580,6 +581,8 @@ void workingset_refault(struct folio *folio, void *shadow) lru_note_cost_refault(folio); mod_lruvec_state(lruvec, WORKINGSET_RESTORE_BASE + file, nr); } +out: + rcu_read_unlock(); } /** -- 2.20.1