[dpdk-dev] [PATCH v2 1/2] virtio: fix queue size and number of descriptors

[Thomas Monjalon]

2015-07-20 11:40, Stephen Hemminger:
> The number of descriptors can be either zero to use the whole
> available ring, or some value smaller. This is used to limit
> the number of mbufs allocated for the receive ring. If more
> descriptors are requested than available the size is silently
> truncated.
[...]
> +	if (nb_desc == 0 || nb_desc > vq_size)
> +		nb_desc = vq_size;

This behaviour should be common to every drivers and explained in the API doxygen:
http://dpdk.org/browse/dpdk/tree/lib/librte_ether/rte_ethdev.h?id=v2.1.0-rc1#n1843