From nobody Fri Dec 19 19:12:42 2025 Received: from out-181.mta0.migadu.com (out-181.mta0.migadu.com [91.218.175.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C333B341061 for ; Wed, 17 Dec 2025 07:33:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.181 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765956809; cv=none; b=RLRIUe7n7niejVcn2uooELYOgdNdYukCSsWsb3B109Eu/w8SSCCsYWOHXJD3fJ35MyMzpKyQ0q9EcS0Uq26VyQhQIA4E46kQOWQRpxPrWxk5pcoDYwpSt/ffnvUjHvLgx9Ci0t5Yvg3MzVRjd0Z/Da5s9/c6aBFg5/DjSZh9FxM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765956809; c=relaxed/simple; bh=OHFZ0LNEpKuTW12Z6kaHmQe+wuzpZdGmCCr/dTwWHsg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aai5pKbfWD0ZDfqbOLV0+Ks62lGrzlfHrBlZzlaibTrh9xjOZ0yL6zeNlU26X3AuKC/uI594spPjYtw+PmEDZMT/X6jggZMQtwdNq07WJJE63f9sxSuy0UTLrE9J3uRH11Mla7bcYg0PAOHlNUx814j9rZAe4MXc0Bqluqzj3UU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Dusw2/39; arc=none smtp.client-ip=91.218.175.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Dusw2/39" 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=1765956801; 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=MLWSJF0nLNh7N5C/0x5tciJKSygGd9RMW0b7OeDmmlY=; b=Dusw2/39bPZpCKgWRmixvObH3oye1W0d2l/EI+/2d4touyB7sDcx41H6ThV+apVJtk/Yzi Mh3NZrd4Dfg10moPMGz7Vru+UO3Po4bUjn2yLFwclZU0w1iEms+dNnGleWkuQpAKJ4cqlr 7M4Gnng6vNejpEIsBHdQU/5f4k5uVa0= 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 22/28] mm: workingset: prevent lruvec release in workingset_activation() Date: Wed, 17 Dec 2025 15:27:46 +0800 Message-ID: <195a8cb47b90e48cd1ec6cb93bc33a8e794847f6.1765956026.git.zhengqi.arch@bytedance.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" 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_activation(). 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 --- mm/workingset.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/workingset.c b/mm/workingset.c index 427ca1a5625e8..d6484f7a3ad28 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -595,8 +595,11 @@ void workingset_activation(struct folio *folio) * Filter non-memcg pages here, e.g. unmap can call * mark_page_accessed() on VDSO pages. */ - if (mem_cgroup_disabled() || folio_memcg_charged(folio)) + if (mem_cgroup_disabled() || folio_memcg_charged(folio)) { + rcu_read_lock(); workingset_age_nonresident(folio_lruvec(folio), folio_nr_pages(folio)); + rcu_read_unlock(); + } } =20 /* --=20 2.20.1