On 09/30/2013 07:35 AM, Rusty Russell wrote:
> 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)?
True, I thought it should be somewhat more easier.
Will post V2.
>
> Cheers,
> Rusty.
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