Jason Wang <jasowang@xxxxxxxxxx> writes:
> 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 use 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@xxxxxxxxxxxxxxx>
> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/net/virtio_net.c | 55 +++++++--------------------------------------
> 1 files changed, 9 insertions(+), 46 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index defec2b..4102c1b 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -127,9 +127,6 @@ 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;
> };
> @@ -1063,7 +1060,6 @@ 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++) {
> @@ -1073,20 +1069,11 @@ 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)
> {
> + cpumask_var_t cpumask;
> int i;
> int cpu;
>
> @@ -1100,15 +1087,21 @@ static void virtnet_set_affinity(struct virtnet_info *vi)
> return;
> }
>
> + if (!alloc_cpumask_var(&cpumask, GFP_KERNEL))
> + return;
> +
> i = 0;
> 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;
> + cpumask_clear(cpumask);
> + cpumask_set_cpu(cpu, cpumask);
> + netif_set_xps_queue(vi->dev, cpumask, i);
> i++;
> }
>
> vi->affinity_hint_set = true;
> + free_cpumask_var(cpumask);
> }
Um, isn't this just cpumask_of(cpu)?
Cheers,
Rusty.
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