[PATCH] net/netvsc: add device argument to configure if NUMA information on the device should be ignored

[Stephen Hemminger]

On Mon, 11 Aug 2025 15:48:07 -0700
longli at linuxonhyperv.com wrote:

> From: Long Li <longli at microsoft.com>
> 
> In most cases, netvsc is used with a VF device. The application generally
> runs with better performance when all the device memory is allocated on
> VF's NUMA node, as the VF device carries most of the data packets.
> 
> But sometimes netvsc may run on a different NUMA node than that of the VF.
> This patches adds a device argument "numa" to allow the application to
> configure if netvsc should be NUMA aware. The default behavior for netvsc
> is that it is NUMA aware. Setting "numa=0" tells netvsc not to be NUMA
> aware.
> 
> Signed-off-by: Long Li <longli at microsoft.com>

Using 0 as "not numa" seems odd because NUMA node 0 is a valid node id.
SOCKET_ID_ANY is defined as -1 in rte_memory.h

The VMBus channels are being created before the device is probed.
And those end up being set before the probe is called.

> @@ -126,7 +183,7 @@ eth_dev_vmbus_allocate(struct rte_vmbus_device *dev, size_t private_data_size)
>  		if (private_data_size) {
>  			eth_dev->data->dev_private =
>  				rte_zmalloc_socket(name, private_data_size,
> -						     RTE_CACHE_LINE_SIZE, dev->device.numa_node);
> +						   RTE_CACHE_LINE_SIZE, dev->device.numa_node);
>  			if (!eth_dev->data->dev_private) {
>  				PMD_DRV_LOG(NOTICE, "can not allocate driver data");
>  				rte_eth_dev_release_port(eth_dev);

No need to change indentation here. Yes alignment with paren is nicer but better
to just focus patch on one thing.

Maybe this should be handled in vmbus then it could get all the allocations right?