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 08ECE1EB5CE; Mon, 20 Apr 2026 15:58:36 +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=1776700716; cv=none; b=KGA4fXxkUHiJJWJ8s6s8Y8kDuQM0717UXmhV7E/HYSxRywiLHFbXaGQ08gwOfhi6dpV8VFsQ0Cs6mfIct91pEP22UPrt0bSIkwufemQ8+nHD5bR/+Q0h43K1WBvLOe4aJ4yNNLdncPz8yhgWbHW8dxHf4/T7Xc4p1Sz/nDBjBHE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776700716; c=relaxed/simple; bh=9AvG9QARWTnCwS6xYa2wF/Okf++da3kSKH85oYegS2Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gRySggyNHyu8qp5LRrc7KIq6QNqg6NgWS+fanVgaVNMCCo6wsH5YoLiEEZOI+sEhFoHQx19EVmugQTJAUIQvZV+wnH/LgPa/YPboPVK+KvBiQ+/pdE/YnLsL+DQc1bPKAH6fMouO9GHR+q1VgPpSMem0a2GxmvmGH5BQCelj6ss= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=u06YKQG/; 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="u06YKQG/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9505DC19425; Mon, 20 Apr 2026 15:58:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776700715; bh=9AvG9QARWTnCwS6xYa2wF/Okf++da3kSKH85oYegS2Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u06YKQG/w2Ak59C0UcGIyQT0hoVNyXDGd1aGIhrKk0gR3epbd5nxdJub5YIHcG8rH CzICl/x9C5RRJpz5noUa1vk03W2n3zxXNKteeE41YPmTmJMaHEkR1S0nNzzopiXoMS 7XlP6Jij8RFoUoMbUy5jr8tQTbhRAocFjYvSr8hM= 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 6.18 059/198] PCI: hv: Set default NUMA node to 0 for devices without affinity info Date: Mon, 20 Apr 2026 17:40:38 +0200 Message-ID: <20260420153937.739752612@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420153935.605963767@linuxfoundation.org> References: <20260420153935.605963767@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 6.18-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 146b43981b278..28b1572974879 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -2486,6 +2486,14 @@ 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