Re: [Patch v3] PCI: hv: Fix NUMA node assignment when kernel boots with custom NUMA topology

From: Leon Romanovsky
Date: Sun Jan 23 2022 - 05:39:17 EST


On Wed, Jan 19, 2022 at 11:59:06AM -0800, longli@xxxxxxxxxxxxxxxxx wrote:
> From: Long Li <longli@xxxxxxxxxxxxx>
>
> When kernel boots with a NUMA topology with some NUMA nodes offline, the PCI
> driver should only set an online NUMA node on the device. This can happen
> during KDUMP where some NUMA nodes are not made online by the KDUMP kernel.
>
> This patch also fixes the case where kernel is booting with "numa=off".
>
> Fixes: 999dd956d838 ("PCI: hv: Add support for protocol 1.3 and support PCI_BUS_RELATIONS2")
>

No blank line here, please

> Signed-off-by: Long Li <longli@xxxxxxxxxxxxx>

Everything below needs to be under "---" marker.

Thanks

>
> Change log:
> v2: use numa_map_to_online_node() to assign a node to device (suggested by
> Michael Kelly <mikelley@xxxxxxxxxxxxx>)
>
> v3: add "Fixes" and check for num_possible_nodes()
> ---
> drivers/pci/controller/pci-hyperv.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index 6c9efeefae1b..b5276e81bb44 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -2129,8 +2129,17 @@ static void hv_pci_assign_numa_node(struct hv_pcibus_device *hbus)
> if (!hv_dev)
> continue;
>
> - if (hv_dev->desc.flags & HV_PCI_DEVICE_FLAG_NUMA_AFFINITY)
> - set_dev_node(&dev->dev, hv_dev->desc.virtual_numa_node);
> + if (hv_dev->desc.flags & HV_PCI_DEVICE_FLAG_NUMA_AFFINITY &&
> + hv_dev->desc.virtual_numa_node < num_possible_nodes())
> + /*
> + * The kernel may boot with some NUMA nodes offline
> + * (e.g. in a KDUMP kernel) or with NUMA disabled via
> + * "numa=off". In those cases, adjust the host provided
> + * NUMA node to a valid NUMA node used by the kernel.
> + */
> + set_dev_node(&dev->dev,
> + numa_map_to_online_node(
> + hv_dev->desc.virtual_numa_node));
>
> put_pcichild(hv_dev);
> }
> --
> 2.25.1
>