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 4F179D29FF1 for ; Wed, 14 Jan 2026 11:34:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B8FB96B00A1; Wed, 14 Jan 2026 06:34:11 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B4D956B00A4; Wed, 14 Jan 2026 06:34:11 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A4BE56B00A1; Wed, 14 Jan 2026 06:34:11 -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 921B66B00A1 for ; Wed, 14 Jan 2026 06:34:11 -0500 (EST) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 5AA848BC0C for ; Wed, 14 Jan 2026 11:34:11 +0000 (UTC) X-FDA: 84330360702.27.ADE7BB6 Received: from out-180.mta0.migadu.com (out-180.mta0.migadu.com [91.218.175.180]) by imf23.hostedemail.com (Postfix) with ESMTP id 9619714000E for ; Wed, 14 Jan 2026 11:34:09 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=YoU4Iky8; spf=pass (imf23.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.180 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=1768390449; 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=642wzt5sbJwBZzq4cokZbiQed5LcU+/gP3D7+Nkqfps=; b=6f5h3Ri5hMrIj5TeP4alIffxU5R36lpmkJUgzoonHAU6MBLv8k/0gX2q4X+kpB1Mm8eJN9 +RdBrctLO7y55XAXoRnpGFIIK15nF84wrGEWM2QtlbIVctaZyYA+O6AdRpi5hotJqK6qwX KwE6DMFURbTTCqTB1wgnJXOLdm5wfQg= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=YoU4Iky8; spf=pass (imf23.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.180 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=1768390449; a=rsa-sha256; cv=none; b=XFU0eeOSk0rGbMCYlO3giM0dCy56afrOrayXsf8AITIPxraTP1XB+OdEqpgl/wLPlYj6YZ j9e8KOGxlJH+CPluyGe4nJXe0PKIifn15NW9mhKvGxw8CzZRCeflMSaIZbfDCwdczsNwi8 xjs9uIj1SrS1LaF6J8Lne82dH8IvJcg= 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=1768390446; 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=642wzt5sbJwBZzq4cokZbiQed5LcU+/gP3D7+Nkqfps=; b=YoU4Iky8HLVffHiXRoGwvgVGzlVPeumBdrWGgRX3FHJHeSUAOcRyplIqVBvX9ZV4PECp/m wVNVWs204n5weRpItm0WRWIOH/sVQ0v44YN9b6egvXft4ZURKshYA+NNhwh95UbPIEutz7 4pgDms5mDpXAR/EA0KbeGFqdVrblkV4= 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 Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH v3 13/30] mm: migrate: prevent memory cgroup release in folio_migrate_mapping() Date: Wed, 14 Jan 2026 19:32:40 +0800 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 9619714000E X-Stat-Signature: 78hqpci44wrhkiiqbefrbx59trs1p5oa X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1768390449-673696 X-HE-Meta: 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 TghsC7YH QaWkG1EdaaJyGI5I2RxPrZHxniwBf0Urrg8feZWK8Ksaa4gAmw1qJ62uDxw6yMSnTUwr9K+l6zDniBb/bpkHuIPkbxLiTmNS7TUtVvvhi4+nVWzkMQpT1qhnq5EEulKVHGMgNHinaEqnRKphmNUt9wYyV06WmbcMENiCg6iDzs61zhwDnildtUiaT6exgRRN6ULa9TxXN1/FNKvkvLlSrjN9FKVAAcXx2FHXVuqSGrlZFroGJDGDKG/bOx0S+5kOcwoZEI48dZHlLL5scyhSYKkcYQLVMGa73sjHUjMcPSBvghm/ojd/Rpe6pRczIpJhZv66h 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 __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 4688b9e38cd2f..1aec3f5509538 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