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 15DFCEFD202 for ; Wed, 25 Feb 2026 07:53:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7974E6B0093; Wed, 25 Feb 2026 02:53:39 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 76E396B009B; Wed, 25 Feb 2026 02:53:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 69A796B009F; Wed, 25 Feb 2026 02:53:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 563946B0093 for ; Wed, 25 Feb 2026 02:53:39 -0500 (EST) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 10B4AC1504 for ; Wed, 25 Feb 2026 07:53:39 +0000 (UTC) X-FDA: 84482214558.23.32D9503 Received: from out-177.mta0.migadu.com (out-177.mta0.migadu.com [91.218.175.177]) by imf07.hostedemail.com (Postfix) with ESMTP id D283140012 for ; Wed, 25 Feb 2026 07:53:35 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=DkMMUtTg; spf=pass (imf07.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.177 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=1772006017; 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=8hyqbb8F2NRNHHFp77Ms/+jViunOCmw3TEFzht4PTD4=; b=ZT5xWOdmTX2c3wQesBuBVBLCvOA4xLMmlGkPPxoLA4nrXjBIzY5kl3049EzqVNHs6M3aV/ 1csfjYV8zdUtWqQQSvGx+LBQ08pUSoYe2rlUfLCaaPapQUFrFOnH68tOUjZ4vvS8s0oCxS QDBHb5A4fzIjVpb3b98YFhnnsYcgIA0= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772006017; a=rsa-sha256; cv=none; b=OmyFlJktxdAU3vujupVl23FInkRA9wUTOvkRL/81RSmkZrkH4MHKLHI8PGezpuGgyI4Ndp eXccAIVajc1IpTepjP/Cq9JUgZbF1xJyu+giXJwhWetd23S6tEj5cdMiKrX99vGyAd8u4M nlBLSKO/dUu622ULZVxgCkiLff1GxII= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=DkMMUtTg; spf=pass (imf07.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.177 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev 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=1772006014; 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=8hyqbb8F2NRNHHFp77Ms/+jViunOCmw3TEFzht4PTD4=; b=DkMMUtTgybWNa/0ty/FNauhU0rxC7aAnYGYaV3c2QbnRCJUGqb0/mocAAWR11N+NIAcKyp 9/LTK3ai1uHLmFYnS/DpH4K2jx5HxBvsqUcHZHY3IMIoJHPfKViPsYmSkiRPd2rDc42pkm zF3Fdl1HnvrqSq41i5dL0qJq3DV//60= 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, yosry.ahmed@linux.dev, 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, bhe@redhat.com, usamaarif642@gmail.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH v5 13/32] mm: migrate: prevent memory cgroup release in folio_migrate_mapping() Date: Wed, 25 Feb 2026 15:52:56 +0800 Message-ID: <0f156c2f1188f256855617953f8305f43e066065.1772005110.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-Stat-Signature: mzhxy447ux93r3gitr8qbk5zhi7zir6p X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: D283140012 X-HE-Tag: 1772006015-941035 X-HE-Meta: U2FsdGVkX19UfS41SQOqfBPRWvcGQew9GaRciDQsbmRoURdWLcRmPx+9s3hbc+mDVZlw6Rwel/ugqsQflMxE+5wegUc3quBmyCEEgLgH7FasGXvGazrpDvMBWiBnjKVr3iIT6OVEihOf5+XuSgXTqJVqMnQz3+h985wGY6i2KEB1pSAVPQtXyAeQbG1qbh4ahwLy+DvjEh8Ovqqn1ItDqV9DF/FUp5XOYsHVyS38lu9hfSHev8DuX0IgV+oFn5Cqpb9sM2blx5fr6FG4r+cnaDoeIQxppsRS9/Wuns9ajdGmg6OYrLKhxLTv7tOs9g34PZgs9Ikr7mtSN0VCYv8DuBveR3ZZ3C4d6w8L5qNcUJhvKJyN2VAAFXV7ghF1MahPhutbHXfQnkTYHxHixRpJg8TcpMb5PxmMWA5fLn3pvPH8bEhVvLMQzR4d1EZURFMczPl9G7UtDEOkE4CYHnQeT+YBj0BL25v+ox9wTJbr79T09EovJvDXidtaWuEZAPoqzMPsQJTHm06yDQrLAnZa5shQzEvUhNQV8wKL15PSHG4/Z8hK1eRM1/XbXqEnPv+nsG2Zz5f2hpw6iaatisBfsVaUDyoCo299ddn0g0bdD0MJq91SMFtJasS7Os30U8RqK/bZYuiLuipRx0ow9O8OKV9Rq2JjNST7V8r3yTaUyxpl/es4FK136qQniq1AU2vaaaULZX9NirFxVexHBHRA4OHutgnQ7YfYL8etUgJ33WKyausXlJlJ819oYmpuQCZeiK9bEq6uY1KKJrkC1wPffyDXdfuXgVPzxn2mZVJI7Li9gv7WPoo9CpaUBXKjFfSvCnIy43/xsInhyI0Sg0K6RnfvUNejxXyF0/zFNA13sK5Lzd8XSA1enmVa3uGJrW0YMkiIwssZGj4lJoiVbeGd5rAfN/JCEnmT8lECxFpy4mPH8/0RKJtEYGpFuc1s84Ze8vd4eKZpJ1Os0SvF2Bw 4nx6Ww6N W+eYy5dHgR6IhyuMau5ZYL+NOiatN0wdKa0QfhTL6GSXmWDqmiUInrHboQT9MOCSBqkAuOo0IgKawdUxGqb5X2yr33kH2VFAv0+ukybDPlnAGTJp+Ulcs3mgKhNT0xQogN9rEEAeJE0MEYkVt+KimuH+l/1IxFkTNYEBUpZHuPyA7CW8XpUK5xNTXjhTXvcZgadPdi6GrD36Xv/mdsW5RNl40bbBNxiSYkKEr/h2TFuko1XachkuA/Wyy6i2PibNAP4nNNlAvV+azU2tmANekFUgE6+89yCs1ZbbfxMHQze9g0eoVl69LjMUGIUb1bOjZwTQt 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 __folio_migrate_mapping(), 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 Acked-by: Johannes Weiner Acked-by: Shakeel Butt --- mm/migrate.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/migrate.c b/mm/migrate.c index 6cc654858da65..27e6103037c29 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -672,6 +672,7 @@ 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); @@ -699,6 +700,7 @@ 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