Re: [net-next rfc v7 3/3] virtio-net: change the number of queues through ethtool
From: Jason Wang <hidden>
Date: 2012-12-03 06:09:44
Also in:
kvm, lkml, virtualization
On Sunday, December 02, 2012 06:09:06 PM Michael S. Tsirkin wrote:
On Tue, Nov 27, 2012 at 06:16:00PM +0800, Jason Wang wrote:quoted
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?
Not sure the value bettwen 1 and max_queue_pairs is useful. But anyway, I can remove this limitation.
Also how does userspace discover what the legal values are?
Userspace only check whether the value is greater than max_queue_pairs.
quoted
+ 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)-- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html