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 DC0C7D64087 for ; Wed, 17 Dec 2025 07:31:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4C61B6B00A5; Wed, 17 Dec 2025 02:31:30 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 483BD6B00A7; Wed, 17 Dec 2025 02:31:30 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3B09D6B00A8; Wed, 17 Dec 2025 02:31:30 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 28C556B00A5 for ; Wed, 17 Dec 2025 02:31:30 -0500 (EST) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id DE7BA160946 for ; Wed, 17 Dec 2025 07:31:29 +0000 (UTC) X-FDA: 84228142698.12.40290DE Received: from out-171.mta0.migadu.com (out-171.mta0.migadu.com [91.218.175.171]) by imf04.hostedemail.com (Postfix) with ESMTP id 420C740006 for ; Wed, 17 Dec 2025 07:31:28 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="Dpym/8wi"; spf=pass (imf04.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.171 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=1765956688; 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=9ugmq4fp6u6Yh4W4K7GQktCJ98/N712HUp8zSOzWPIU=; b=KrJ5Kk0eEYv/hZ41q8PJ91tCHRFb9HIifmNu91y54nHFjiORqStn0G4c9PzoTw+eOrUPIz WME2L7oQC31vQahKfkYNFoFQrogwLvRgAgWj1e+IJijIJmKivsbsIwHCFsQRp9zKSYS7VV WG09rBIZO3Q5e+QSDerig5fHBG/DP04= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="Dpym/8wi"; spf=pass (imf04.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.171 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=1765956688; a=rsa-sha256; cv=none; b=HlJWMi/aTG/YZi96NxTLqJyTlKXpXzkXMTpEwZ9tPQWmOU4ZyHIHlXsy8jB01HilH6aTxv qTLB4l7daX6jln7oWvmqd4ds5cbvYJwtGHF2uyaTZwqWXPLoERk9g9WXBCybzdsYARpBPF 1Gg9tbapVC89XpMgfEB7yFh9EKKWcXU= 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=1765956681; 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=9ugmq4fp6u6Yh4W4K7GQktCJ98/N712HUp8zSOzWPIU=; b=Dpym/8wiT7J1ZVKeNfPt+C3A+L7GdRuNhMyDPTQKIMteFSS5QIJYRZCFJNdHpiMS1ez25Y 7X1VGxT67Up330JCOXDXoI1rHcxe2C6xowJgyhm7GBrskvebqMmSp66/G9AOsDH4sMQa4I QgiaDtXzXOzyT4f+DsixHyZtIUbp+CY= 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 13/28] mm: migrate: prevent memory cgroup release in folio_migrate_mapping() Date: Wed, 17 Dec 2025 15:27:37 +0800 Message-ID: <1554459c705a46324b83799ede617b670b9e22fb.1765956025.git.zhengqi.arch@bytedance.com> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: 7e3rjwgsppsmxr4ttrzzmjozmzyosym5 X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 420C740006 X-HE-Tag: 1765956687-1895 X-HE-Meta: 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 4sS0qJ/6 UfkdvZcB+oKdALeF9HVG1E3ncgJpWwts5eZ+FrTZT1jhJEMGBIV0hpr6zpP5MfbRHdJzcjaUxuZGvpBVR+V8EqjUS0INVaUoLGg7td8MEXZHO5h6aso5cPp14igSa7eAabnjJOYXDJ429IjGbExQLeC3QckBr9P3A0Uj9ML/i2aEmMkE2ol//b+UYZdwzLkW9w3Uf9bq+BDGEbVR8Xvk96eUTRSjXq9kFpHj+GDN9Axo+gS2W270D19wM3X6U0VT+U15D 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 Reviewed-by: Harry Yoo --- mm/migrate.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/migrate.c b/mm/migrate.c index 5169f9717f606..8bcd588c083ca 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -671,6 +671,7 @@ 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); @@ -698,6 +699,7 @@ 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