From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 550493438A8; Sat, 30 May 2026 16:22:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780158151; cv=none; b=I1wJ5BZ8QbMlnXxEjjsLMsoMtGoLBRVlMPgyuibl4bCxZlDcqxqaOyrvIbP/dinZd7RW/Doq67zhGu6dqkszDFemUVceOF1xDeJQyXOgXKieDLMVu32onyOz4PDrNcLpEjP9vRFpEcCoq88ot6KP86diwAcJzZaORROWjBalkkc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780158151; c=relaxed/simple; bh=4CBIHJvUFWvhAu0e7/SJzzueODCAP2aKWCWpkT6dOlk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IEIg1+S3PeY8l/Gap8UsVHmLpUijOFoQ3cBRC/aNgDtEHihUCi9NB6pFJA9b/hGvQV/DVnuBuRAAMryT0YLtHX5M6p4Hzy8xYjY7+7eLOEuskvXT0RQ8t5PsxQlLP+HEFUH0P5A0NIpe0AxdKEeRcsDnHeu1O2+Jfri+NYgHbjg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=n1UyhNuW; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="n1UyhNuW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8594D1F00893; Sat, 30 May 2026 16:22:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780158150; bh=B6G41XdiyuSgB6t8HDiWc2zKFumrG8flONUOunsT6os=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=n1UyhNuWQdS3yN39LYugUKByhEai+orBzdNFOr5dsME2KlDAsetbTysGgtsmV8fpu M1vJ0HUqDyBKEyrs3GnCFkkeQHSZ4sdM65TwzDT+fTXeLxzWfaPqAtIfYEeYk2g2S7 /U5pvkxYww9SBwaLHbgC4ur/PjNWJWShvIXPoeFU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Long Li , Michael Kelley , Wei Liu , Sasha Levin Subject: [PATCH 6.1 026/969] PCI: hv: Set default NUMA node to 0 for devices without affinity info Date: Sat, 30 May 2026 17:52:30 +0200 Message-ID: <20260530160301.167843018@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160300.485627683@linuxfoundation.org> References: <20260530160300.485627683@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Long Li [ Upstream commit 7b3b1e5a87b2f5e35c52b5386d7c327be869454f ] When hv_pci_assign_numa_node() processes a device that does not have HV_PCI_DEVICE_FLAG_NUMA_AFFINITY set or has an out-of-range virtual_numa_node, the device NUMA node is left unset. On x86_64, the uninitialized default happens to be 0, but on ARM64 it is NUMA_NO_NODE (-1). Tests show that when no NUMA information is available from the Hyper-V host, devices perform best when assigned to node 0. With NUMA_NO_NODE the kernel may spread work across NUMA nodes, which degrades performance on Hyper-V, particularly for high-throughput devices like MANA. Always set the device NUMA node to 0 before the conditional NUMA affinity check, so that devices get a performant default when the host provides no NUMA information, and behavior is consistent on both x86_64 and ARM64. Fixes: 999dd956d838 ("PCI: hv: Add support for protocol 1.3 and support PCI_BUS_RELATIONS2") Signed-off-by: Long Li Reviewed-by: Michael Kelley Signed-off-by: Wei Liu Signed-off-by: Sasha Levin --- drivers/pci/controller/pci-hyperv.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index 09491d06589ee..58430ca37bbdf 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -2291,6 +2291,14 @@ static void hv_pci_assign_numa_node(struct hv_pcibus_device *hbus) if (!hv_dev) continue; + /* + * If the Hyper-V host doesn't provide a NUMA node for the + * device, default to node 0. With NUMA_NO_NODE the kernel + * may spread work across NUMA nodes, which degrades + * performance on Hyper-V. + */ + set_dev_node(&dev->dev, 0); + if (hv_dev->desc.flags & HV_PCI_DEVICE_FLAG_NUMA_AFFINITY && hv_dev->desc.virtual_numa_node < num_possible_nodes()) /* -- 2.53.0