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

[Xuan Zhuo <xuanzhuo@linux.alibaba.com>]

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)) {
>

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