Re: [PATCH 3/3] driver: vHost support to free consumed buffers

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri, 16 Dec 2016 07:48:51 -0500
Billy McFall <bmcfall@redhat.com> wrote:

> Add support to the vHostdriver for the new API to force free consumed
> buffers on TX ring. vHost does not cache the mbufs so there is no work
> to do.
> 
> Signed-off-by: Billy McFall <bmcfall@redhat.com>
> ---
>  drivers/net/vhost/rte_eth_vhost.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
> index 766d4ef..6493d56 100644
> --- a/drivers/net/vhost/rte_eth_vhost.c
> +++ b/drivers/net/vhost/rte_eth_vhost.c
> @@ -939,6 +939,16 @@ eth_queue_release(void *q)
>  }
>  
>  static int
> +eth_tx_done_cleanup(void *txq __rte_unused, uint32_t free_cnt __rte_unused)
> +{
> +	/*
> +	 * vHost does not hang onto mbuf. eth_vhost_tx() copies packet data
> +	 * and releases mbuf, so nothing to cleanup.
> +	 */
> +	return 0;
> +}
> +
> +static int
>  eth_link_update(struct rte_eth_dev *dev __rte_unused,
>  		int wait_to_complete __rte_unused)
>  {
> @@ -979,6 +989,7 @@ static const struct eth_dev_ops ops = {
>  	.tx_queue_setup = eth_tx_queue_setup,
>  	.rx_queue_release = eth_queue_release,
>  	.tx_queue_release = eth_queue_release,
> +	.tx_done_cleanup = eth_tx_done_cleanup,
>  	.link_update = eth_link_update,
>  	.stats_get = eth_stats_get,
>  	.stats_reset = eth_stats_reset,

Rather than having to change every drive, why not make this the default
behavior?