* Re: [RHEL7]virtio-net: switch to use XPS to choose txq
[not found] <20191220114813.7052-1-lulu@redhat.com>
@ 2019-12-23 2:27 ` Jason Wang
0 siblings, 0 replies; only message in thread
From: Jason Wang @ 2019-12-23 2:27 UTC (permalink / raw)
To: Cindylu, virtualization, mst, jfreimann, rusty, jmaxwell
On 2019/12/20 下午7:48, Cindylu wrote:
> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1769479
> Upstream Status: 9bb8ca86075f37d3c169b9c46f8e7c6d3165e18f
> Brew: https://brewweb.devel.redhat.com/taskinfo?taskID=25482050
> Tested: verified by customer
>
> commit 9bb8ca86075f37d3c169b9c46f8e7c6d3165e18f
> Author: Jason Wang <jasowang@redhat.com>
> Date: Tue Nov 5 18:19:45 2013 +0800
>
> virtio-net: switch to use XPS to choose txq
>
> We used to use a percpu structure vq_index to record the cpu to queue
> mapping, this is suboptimal since it duplicates the work of XPS and
> loses all other XPS functionality such as allowing user to configure
> their own transmission steering strategy.
>
> So this patch switches to use XPS and suggest a default mapping when
> the number of cpus is equal to the number of queues. With XPS support,
> there's no need for keeping per-cpu vq_index and .ndo_select_queue(),
> so they were removed also.
>
> Cc: Rusty Russell <rusty@rustcorp.com.au>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Acked-by: Rusty Russell <rusty@rustcorp.com.au>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> ---
> drivers/net/virtio_net.c | 49 ++--------------------------------------
> 1 file changed, 2 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 61c64d92211..d5335774c60 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -125,9 +125,6 @@ struct virtnet_info {
> /* Does the affinity hint is set for virtqueues? */
> bool affinity_hint_set;
>
> - /* Per-cpu variable to show the mapping from CPU to virtqueue */
> - int __percpu *vq_index;
> -
> /* CPU hot plug notifier */
> struct notifier_block nb;
>
> @@ -1124,7 +1121,6 @@ static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
> static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
> {
> int i;
> - int cpu;
>
> if (vi->affinity_hint_set) {
> for (i = 0; i < vi->max_queue_pairs; i++) {
> @@ -1134,16 +1130,6 @@ static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
>
> vi->affinity_hint_set = false;
> }
> -
> - i = 0;
> - for_each_online_cpu(cpu) {
> - if (cpu == hcpu) {
> - *per_cpu_ptr(vi->vq_index, cpu) = -1;
> - } else {
> - *per_cpu_ptr(vi->vq_index, cpu) =
> - ++i % vi->curr_queue_pairs;
> - }
> - }
> }
>
> static void virtnet_set_affinity(struct virtnet_info *vi)
> @@ -1165,7 +1151,7 @@ static void virtnet_set_affinity(struct virtnet_info *vi)
> for_each_online_cpu(cpu) {
> virtqueue_set_affinity(vi->rq[i].vq, cpu);
> virtqueue_set_affinity(vi->sq[i].vq, cpu);
> - *per_cpu_ptr(vi->vq_index, cpu) = i;
> + netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
> i++;
> }
>
> @@ -1268,29 +1254,6 @@ static const struct ethtool_ops virtnet_ethtool_ops = {
> .get_channels = virtnet_get_channels,
> };
>
> -/* To avoid contending a lock hold by a vcpu who would exit to host, select the
> - * txq based on the processor id.
> - */
> -static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb,
> - void *accel_priv, select_queue_fallback_t fallback)
> -{
> - int txq;
> - struct virtnet_info *vi = netdev_priv(dev);
> -
> - if (skb_rx_queue_recorded(skb)) {
> - txq = skb_get_rx_queue(skb);
> - } else {
> - txq = *__this_cpu_ptr(vi->vq_index);
> - if (txq == -1)
> - txq = 0;
> - }
> -
> - while (unlikely(txq >= dev->real_num_tx_queues))
> - txq -= dev->real_num_tx_queues;
> -
> - return txq;
> -}
> -
> static int virtnet_get_phys_port_name(struct net_device *dev, char *buf,
> size_t len)
> {
> @@ -1317,7 +1280,6 @@ static const struct net_device_ops virtnet_netdev = {
> .ndo_get_stats64 = virtnet_stats,
> .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
> .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
> - .ndo_select_queue = virtnet_select_queue,
> #ifdef CONFIG_NET_POLL_CONTROLLER
> .ndo_poll_controller = virtnet_netpoll,
> #endif
> @@ -1642,10 +1604,6 @@ static int virtnet_probe(struct virtio_device *vdev)
> if (vi->stats == NULL)
> goto free;
>
> - vi->vq_index = alloc_percpu(int);
> - if (vi->vq_index == NULL)
> - goto free_stats;
> -
> INIT_WORK(&vi->config_work, virtnet_config_changed_work);
>
> /* If we can receive ANY GSO packets, we must allocate large ones. */
> @@ -1695,7 +1653,7 @@ static int virtnet_probe(struct virtio_device *vdev)
> /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
> err = init_vqs(vi);
> if (err)
> - goto free_index;
> + goto free_stats;
>
> netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
> netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
> @@ -1764,8 +1722,6 @@ free_failover:
> free_vqs:
> cancel_delayed_work_sync(&vi->refill);
> virtnet_del_vqs(vi);
> -free_index:
> - free_percpu(vi->vq_index);
> free_stats:
> free_percpu(vi->stats);
> free:
> @@ -1801,7 +1757,6 @@ static void virtnet_remove(struct virtio_device *vdev)
> remove_vq_common(vi);
>
>
> - free_percpu(vi->vq_index);
> free_percpu(vi->stats);
> free_netdev(vi->dev);
> }
Acked-by: Jason Wang <jasowang@redhat.com>
Thanks
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