Re: [net-next rfc v7 3/3] virtio-net: change the number of queues through ethtool
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2012-12-02 16:06:28
Also in:
kvm, lkml, virtualization
On Tue, Nov 27, 2012 at 06:16:00PM +0800, Jason Wang wrote:
quoted hunk ↗ jump to hunk
This patch implement the {set|get}_channels method of ethool to allow user to change the number of queues dymaically when the device is running. This would let the user to configure it on demand. Signed-off-by: Jason Wang <redacted> --- drivers/net/virtio_net.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 files changed, 41 insertions(+), 0 deletions(-)diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index bcaa6e5..f08ec2a 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c@@ -1578,10 +1578,51 @@ static struct virtio_driver virtio_net_driver = { #endif }; +/* TODO: Eliminate OOO packets during switching */ +static int virtnet_set_channels(struct net_device *dev, + struct ethtool_channels *channels) +{ + struct virtnet_info *vi = netdev_priv(dev); + u16 queue_pairs = channels->combined_count; + + /* We don't support separate rx/tx channels. + * We don't allow setting 'other' channels. + */ + if (channels->rx_count || channels->tx_count || channels->other_count) + return -EINVAL; + + /* Only two modes were support currently */ + if (queue_pairs != vi->max_queue_pairs && queue_pairs != 1) + return -EINVAL; +
Why the limitation? Also how does userspace discover what the legal values are?
+ vi->curr_queue_pairs = queue_pairs;
+ BUG_ON(virtnet_set_queues(vi));
+
+ netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
+ netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
+
+ return 0;
+}
+
+static void virtnet_get_channels(struct net_device *dev,
+ struct ethtool_channels *channels)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+
+ channels->combined_count = vi->curr_queue_pairs;
+ channels->max_combined = vi->max_queue_pairs;
+ channels->max_other = 0;
+ channels->rx_count = 0;
+ channels->tx_count = 0;
+ channels->other_count = 0;
+}
+
static const struct ethtool_ops virtnet_ethtool_ops = {
.get_drvinfo = virtnet_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_ringparam = virtnet_get_ringparam,
+ .set_channels = virtnet_set_channels,
+ .get_channels = virtnet_get_channels,
};
static int __init init(void)
--
1.7.1