Re: [RFC PATCH net-next 02/12] vhost_net: introduce vhost_exceeds_weight()

Jesse Brandeburg
2018-05-21T16:29:27Z

On Mon, 21 May 2018 17:04:23 +0800 Jason wrote:
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> drivers/vhost/net.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 15d191a..de544ee 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -479,6 +479,12 @@ static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter,
> return len;
> }
>
> +static bool vhost_exceeds_weight(int pkts, int total_len)
> +{
> + return unlikely(total_len >= VHOST_NET_WEIGHT) ||
> + unlikely(pkts >= VHOST_NET_PKT_WEIGHT);

I was going to say just one unlikely, but then the caller of this
function also says unlikely(vhost_exceeds...), so I think you should
just drop the unlikely statements here (both of them)

> +}
> +
> /* Expects to be always run from workqueue - which acts as
> * read-size critical section for our kind of RCU. */
> static void handle_tx(struct vhost_net *net)
> @@ -570,7 +576,6 @@ static void handle_tx(struct vhost_net *net)
> msg.msg_control = NULL;
> ubufs = NULL;
> }
> -

unrelated whitespace changes?

> total_len += len;
> if (total_len < VHOST_NET_WEIGHT &&
> !vhost_vq_avail_empty(&net->dev, vq) &&
> @@ -600,8 +605,7 @@ static void handle_tx(struct vhost_net *net)
> else
> vhost_zerocopy_signal_used(net, vq);
> vhost_net_tx_packet(net);
> - if (unlikely(total_len >= VHOST_NET_WEIGHT) ||
> - unlikely(++sent_pkts >= VHOST_NET_PKT_WEIGHT)) {
> + if (unlikely(vhost_exceeds_weight(++sent_pkts, total_len))) {
> vhost_poll_queue(&vq->poll);
> break;
> }
> @@ -887,8 +891,7 @@ static void handle_rx(struct vhost_net *net)
> if (unlikely(vq_log))
> vhost_log_write(vq, vq_log, log, vhost_len);
> total_len += vhost_len;
> - if (unlikely(total_len >= VHOST_NET_WEIGHT) ||
> - unlikely(++recv_pkts >= VHOST_NET_PKT_WEIGHT)) {
> + if (unlikely(vhost_exceeds_weight(++recv_pkts, total_len))) {
> vhost_poll_queue(&vq->poll);
> goto out;
> }