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 7D421CCF9E0 for ; Tue, 28 Oct 2025 14:03:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DAEA580158; Tue, 28 Oct 2025 10:03:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D37E18013F; Tue, 28 Oct 2025 10:03:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C002780158; Tue, 28 Oct 2025 10:03:35 -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 AB9AF8013F for ; Tue, 28 Oct 2025 10:03:35 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 50A1788865 for ; Tue, 28 Oct 2025 14:03:35 +0000 (UTC) X-FDA: 84047690790.12.B1153B0 Received: from out-179.mta0.migadu.com (out-179.mta0.migadu.com [91.218.175.179]) by imf07.hostedemail.com (Postfix) with ESMTP id 6CF2E40020 for ; Tue, 28 Oct 2025 14:03:33 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=MbNGCPjX; spf=pass (imf07.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.179 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=1761660213; 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=4oMNhuRAi27cTHrhaZltmQus/gsvCkLckLS+iJA38nw=; b=F8MwftyiZ5XjhCrjTw3LOahPeWwER1N1tOP0y1ioW9FMZ6LJalZ87Kgkw5mZgnvshBuvk8 VhV3yaOTHWDdeMLI/N6z0pKvxnMGez2MckwhTOD7nclBDjy0DIIN/0xxynvZZeWR5M+Zgg AUudYJi39dI+JNXt990LLGVlZPEpZ48= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=MbNGCPjX; spf=pass (imf07.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.179 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=1761660213; a=rsa-sha256; cv=none; b=ErwA8X3C0d7prsn90xES9kR8AR6Fbz6ZTiMGUPPZl1cEVWLYJArToUyWZgjrC9rtTV6Y3L O07PPQXGRsXWeJpplbp9IDY+GGGtmngYiHzSE87dq5S5XiL8DbWeS2Wk1mfMTIa9mU97k3 7WSugDWtUL+xIB+dl/zLb2ovOaKmTpA= 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=1761660211; 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=4oMNhuRAi27cTHrhaZltmQus/gsvCkLckLS+iJA38nw=; b=MbNGCPjX2eMT1kl0IeUIiPgzGhk9+LXl8jF+2FbuFvx9cFOCbfxtLGhzIX0YHs43F8rw0q MOMy/qbzVn5dCpvh5smAIvBZR6AFMi1nbijvzmHsPNRZR6Crox1yE20Tq1CRzKFdbfjJ5E /C/lzYoQFfNgDHCjcMQg1QkXB/WzS4c= 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@redhat.com, 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, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH v1 12/26] mm: migrate: prevent memory cgroup release in folio_migrate_mapping() Date: Tue, 28 Oct 2025 21:58:25 +0800 Message-ID: <2ff7f2f1ac1d3884c549d9b5134322df21703018.1761658310.git.zhengqi.arch@bytedance.com> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 6CF2E40020 X-Stat-Signature: wtuoh4yd3dq8utrdsubqic4xy7fk1w6i X-Rspam-User: X-HE-Tag: 1761660213-725993 X-HE-Meta: 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 qWzNqrOb DqdEbPAwUY7UStlak/MquJsMMWfKtwoUngsJWXQHmL98GVopCJdmvI9qp21ycCKwcmBPx39qX/HvhQ0ln8olWUw+hCji+KmgFgp+VFwDb5NolpHps/NTemrLpUnb5TLsdip6Gd27DDnRFnOGx5G+3wQmhPgtNGHfvCESf4u4/Eup1JOZNAoQQWJn2cys70hg1Td22b23VdFMpwcR/rYzvV+g5N9SEZvHN+YjVvnS65SHXUW4n/dgrWCx7AkkoB4S5oEKuus64cqoe7qc= 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. To ensure safety, it will only be appropriate to hold the rcu read lock or acquire a reference to the memory cgroup returned by folio_memcg(), thereby preventing it from being released. In the current patch, the rcu read lock is employed to safeguard against the release of the memory cgroup in folio_migrate_mapping(). This serves as a preparatory measure for the reparenting of the LRU pages. Signed-off-by: Muchun Song Signed-off-by: Qi Zheng --- mm/migrate.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/migrate.c b/mm/migrate.c index ceee354ef2152..cdab1b652c530 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -664,6 +664,7 @@ static int __folio_migrate_mapping(struct address_space *mapping, struct lruvec *old_lruvec, *new_lruvec; struct mem_cgroup *memcg; + rcu_read_lock(); memcg = folio_memcg(folio); old_lruvec = mem_cgroup_lruvec(memcg, oldzone->zone_pgdat); new_lruvec = mem_cgroup_lruvec(memcg, newzone->zone_pgdat); @@ -691,6 +692,7 @@ static int __folio_migrate_mapping(struct address_space *mapping, __mod_lruvec_state(new_lruvec, NR_FILE_DIRTY, nr); __mod_zone_page_state(newzone, NR_ZONE_WRITE_PENDING, nr); } + rcu_read_unlock(); } local_irq_enable(); -- 2.20.1