From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CDB10606A31B for ; Tue, 27 Oct 2026 00:14:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=hmboVRqb; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=gGjiBpH9 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Date: Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Cc:To:Subject: From:Message-ID:MIME-Version:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=6+Qn83otNkpPLLetvOkPpEarChsgTvrJSByi11bVmzY=; b=hmboVRqbc3a6EZouK5yIsI2zMt 3Dhu8P0hyryThBVFdVlanpJ9UM3R6866IfHmJOT/xa19QpbcpDWu5RH2RyGuH6ZFYHZnouD3Ne129 83L2DQAGgY7IXH9CIerxD76R4YfpjRyHbdFj+bYQ7bqrWyWxLQFvgzOlyVl8UFtF4IqgDRkYcfoCF Aqt+mc2QK5lBWvVndqmqD3JynfvD14OmjcY4a/r8GVdduBR79tC5a/rm89UpRSx5IdUueKr3AnJ/v dmvxSTSFN2ceEPlfP6MSlmXjWfH4G7rlVJnGkrnzWH7fZleBrKAgt+gkiRRR8OAd8E5kMBEQJSoa+ vaUYOIig==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUpi-00000003WKm-2CC8; Tue, 27 Oct 2026 00:14:30 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUph-00000003WJj-22rN for kexec@lists.infradead.org; Tue, 27 Oct 2026 00:14:29 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 251BE414D3; Tue, 27 Oct 2026 00:14:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 097761F01825; Tue, 27 Oct 2026 00:14:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793060069; bh=6+Qn83otNkpPLLetvOkPpEarChsgTvrJSByi11bVmzY=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=gGjiBpH9zEHAOaJeynoRMGOMQzuVPBvmdCO/C176mh23wovy+6zQxACCP6Cb7cOse ch2a88j5AT8zZ9gKSIt4kesZBVN0TiRM8A5xcbbjZwG2Bju6HIKkWaHzDxQnX0+xzT JsOHz6wZfdGEggCecg5q0oMeAfU11/pLkCSWAnSu9s/ikx+d4hYab2z/bU74rZuuq/ 0vs0pbrfEqXvgIyRwJifaP80HJqvtnyXPzJocdtSAB6pJsePFNcv+lb4Dcyw7QcnM9 oqioli5GTEfYduTxzna+Ef4lQqjYXSabIWDl87Id3UYlQW0x8nptvKZF9SrxxpNGyy CFyhHWgLsHyQw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 45/46] mm/memory-tiers: unregister empty tiers outside memory_tier_lock To: =?utf-8?b?RGF2aWQgSGlsZGVuYnJhbmQgKEFybSk=?= , "Andrew Morton" , "Johannes Weiner" , "Michal Hocko" , "Qi Zheng" , "Shakeel Butt" , "Lorenzo Stoakes" , "Kairui Song" , "Barry Song" , "Axel Rasmussen" , "Yuanchu Xie" , "Wei Xu" , "Baoquan He" , "Baolin Wang" , "Liam R. Howlett" , "Vlastimil Babka" , "Mike Rapoport" , "Suren Baghdasaryan" , "Michal Hocko" , "Kees Cook" , "Peter Zijlstra" , "Jann Horn" , "Pedro Falcato" , "Hugh Dickins" , "Pasha Tatashin" , "Pratyush Yadav" , =?utf-8?b?TWF0dGhldyBXaWxjb3ggKE9yYWNsZSk=?= , "Jan Kara" , "Zi Yan" , "Lance Yang" , "Rik van Riel" , "Harry Yoo" , "Alistair Popple" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Usama Arif" , "Kiryl Shutsemau" , "Matthew Brost" , "John Hubbard" , "Peter Xu" , "Will Deacon" , "Aneesh Kumar K.V" , "Nick Piggin" , "Oscar Salvador" , "Minchan Kim" , "Muchun Song" , "Xu Xin" , "Chengming Zhou" , "Chris Li" , "Kemeng Shi" , "Nhat Pham" , "Youngjun Park" , "Gregory Price" , "Joshua Hahn" , "Rakie Kim" , "Ying Huang" , "Jason Gunthorpe" Cc: kexec@lists.infradead.org, "Josef Bacik" In-Reply-To: <20261027-fixes_core-v1-45-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-45-6f74bec9a5bb@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 27 Oct 2026 00:14:25 +0000 X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "kexec" X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: > When offlining a node's last memory empties its tier, > clear_node_memory_tier() calls device_unregister() while holding > memory_tier_lock. A concurrent sysfs read can hold a kernfs active > reference and block in nodelist_show() on that mutex. device_unregister() > then waits in kernfs_drain() for the read to finish and release its active > reference, while the reader waits for the offlining task to release the > mutex. >=20 > Return the node's former tier from clear_node_memory_tier(), making the > helper more similar to set_node_memory_tier(), which also returns a > memory_tier pointer. Let the caller unlink an empty tier under > memory_tier_lock before rebuilding demotion targets, then unregister its > device after dropping the lock. >=20 > Fixes: 9832fb87834e ("mm/demotion: expose memory tier details via sysfs") > Cc: stable@vger.kernel.org > Reported-by: Josef Bacik > Signed-off-by: David Hildenbrand (Arm) Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261027-fixes_core= -v1-0-6f74bec9a5bb@kernel.org?part=3D45