Re: [PATCH v7 25/26] virtio_net: set the default max ring size by find_vqs()

Xuan Zhuo
2022-03-09T09:36:28Z

On Wed, 9 Mar 2022 17:28:21 +0800, Jason Wang <jasowang@redhat.com> wrote:
>
> 在 2022/3/8 下午8:35, Xuan Zhuo 写道:
> > Use virtio_find_vqs_ctx_size() to specify the maximum ring size of tx,
> > rx at the same time.
> >
> > | rx/tx ring size
> > -------------------------------------------
> > speed == UNKNOWN or < 10G| 1024
> > speed < 40G | 4096
> > speed >= 40G | 8192
> >
> > Call virtnet_update_settings() once before calling init_vqs() to update
> > speed.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > ---
> > drivers/net/virtio_net.c | 42 ++++++++++++++++++++++++++++++++++++----
> > 1 file changed, 38 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index ffff323dcef0..f1bdc6ce21c3 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -2977,6 +2977,29 @@ static unsigned int mergeable_min_buf_len(struct virtnet_info *vi, struct virtqu
> > (unsigned int)GOOD_PACKET_LEN);
> > }
> >
> > +static void virtnet_config_sizes(struct virtnet_info *vi, u32 *sizes)
> > +{
> > + u32 i, rx_size, tx_size;
> > +
> > + if (vi->speed == SPEED_UNKNOWN || vi->speed < SPEED_10000) {
> > + rx_size = 1024;
> > + tx_size = 1024;
> > +
> > + } else if (vi->speed < SPEED_40000) {
> > + rx_size = 1024 * 4;
> > + tx_size = 1024 * 4;
> > +
> > + } else {
> > + rx_size = 1024 * 8;
> > + tx_size = 1024 * 8;
> > + }
> > +
> > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > + sizes[rxq2vq(i)] = rx_size;
> > + sizes[txq2vq(i)] = tx_size;
> > + }
> > +}
> > +
> > static int virtnet_find_vqs(struct virtnet_info *vi)
> > {
> > vq_callback_t **callbacks;
> > @@ -2984,6 +3007,7 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
> > int ret = -ENOMEM;
> > int i, total_vqs;
> > const char **names;
> > + u32 *sizes;
> > bool *ctx;
> >
> > /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
> > @@ -3011,10 +3035,15 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
> > ctx = NULL;
> > }
> >
> > + sizes = kmalloc_array(total_vqs, sizeof(*sizes), GFP_KERNEL);
> > + if (!sizes)
> > + goto err_sizes;
> > +
> > /* Parameters for control virtqueue, if any */
> > if (vi->has_cvq) {
> > callbacks[total_vqs - 1] = NULL;
> > names[total_vqs - 1] = "control";
> > + sizes[total_vqs - 1] = 0;
>
>
> Nit: Do we need a sane value for the control vq? (e.g 64)

I think it can.

Thanks.

>
> Thanks
>
>
> > }
> >
> > /* Allocate/initialize parameters for send/receive virtqueues */
> > @@ -3029,8 +3058,10 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
> > ctx[rxq2vq(i)] = true;
> > }
> >
> > - ret = virtio_find_vqs_ctx(vi->vdev, total_vqs, vqs, callbacks,
> > - names, ctx, NULL);
> > + virtnet_config_sizes(vi, sizes);
> > +
> > + ret = virtio_find_vqs_ctx_size(vi->vdev, total_vqs, vqs, callbacks,
> > + names, ctx, NULL, sizes);
> > if (ret)
> > goto err_find;
> >
> > @@ -3050,6 +3081,8 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
> >
> >
> > err_find:
> > + kfree(sizes);
> > +err_sizes:
> > kfree(ctx);
> > err_ctx:
> > kfree(names);
> > @@ -3368,6 +3401,9 @@ static int virtnet_probe(struct virtio_device *vdev)
> > vi->curr_queue_pairs = num_online_cpus();
> > vi->max_queue_pairs = max_queue_pairs;
> >
> > + virtnet_init_settings(dev);
> > + virtnet_update_settings(vi);
> > +
> > /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
> > err = init_vqs(vi);
> > if (err)
> > @@ -3380,8 +3416,6 @@ static int virtnet_probe(struct virtio_device *vdev)
> > netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
> > netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
> >
> > - virtnet_init_settings(dev);
> > -
> > if (virtio_has_feature(vdev, VIRTIO_NET_F_STANDBY)) {
> > vi->failover = net_failover_create(vi->dev);
> > if (IS_ERR(vi->failover)) {