From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A92DF19A288; Fri, 24 Apr 2026 13:34:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777037680; cv=none; b=eRN73DlA9DfCUZU81a2UIkTer0bGkp8MelC+XXVHqpm1LyAXtLrcDcauyyZd2n36KelWVIsrXmOh+OMd7sQaM5NwWfRJlTViRGW+yL/ACgyUOAvxj0eY2EHRjj1boPeZ5KIe+rutzjLvYeV8WrdBOV2uYXlwfEXYjWJldwS8oIg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777037680; c=relaxed/simple; bh=Zy+43tYtn+UVgzgWTydLeI4bTtkPMSo3kfDFBQ0DqHc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZSUoIDA54avTYK35r5u+h793szZ7nHQftMdHLTiEn3jQs+Zny2PMXxOIlU6GDq2VNqTmXJUNowc7viFPzbdfUaaDXN/S+RcNMYBsXJcgJdRE2Rr7hSzCYEZoZ9T7r8oud0lyfNkV+ri9cQ+mTvgT/i1x4UYjS4bxIv8yrbe3flA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RUVYb15o; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RUVYb15o" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FA89C19425; Fri, 24 Apr 2026 13:34:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1777037680; bh=Zy+43tYtn+UVgzgWTydLeI4bTtkPMSo3kfDFBQ0DqHc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RUVYb15oSuNokjT8tAgkscx1GRnHDzUARRueL293N3P9AR8sEuqL2WCsw0UauP+0O oJwS2GtMKEKwZaog+zkAW/Rfjot6M1NNmp214BJ3FnHNCE6p79hRRFU5xpE5+gXYZx 6sG5XKYeprD7LavYOoKc3KMJsEkobUQq36hFWu30= 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 6.6 029/166] PCI: hv: Set default NUMA node to 0 for devices without affinity info Date: Fri, 24 Apr 2026 15:29:03 +0200 Message-ID: <20260424132538.960360006@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260424132532.812258529@linuxfoundation.org> References: <20260424132532.812258529@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-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 4c34909810d8e..e379ed9b5d2eb 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -2371,6 +2371,14 @@ 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