From: Caleb Raitto <caraitto@xxxxxxxxxx> Always set the affinity hint, even if #cpu != #vq. Handle the case where #cpu > #vq (including when #cpu % #vq != 0) and when #vq > #cpu (including when #vq % #cpu != 0). Signed-off-by: Caleb Raitto <caraitto@xxxxxxxxxx> Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx> Acked-by: Jon Olson <jonolson@xxxxxxxxxx> --- drivers/net/virtio_net.c | 42 ++++++++++++++++++++++++++-------------- 1 file changed, 27 insertions(+), 15 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 43fabc0eb4d2..eb00ae6ee475 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -31,6 +31,7 @@ #include <linux/average.h> #include <linux/filter.h> #include <linux/netdevice.h> +#include <linux/kernel.h> #include <linux/pci.h> #include <net/route.h> #include <net/xdp.h> @@ -1888,30 +1889,41 @@ static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu) static void virtnet_set_affinity(struct virtnet_info *vi) { - int i; - int cpu; + cpumask_var_t mask; + int stragglers; + int group_size; + int i, j, cpu; + int num_cpu; + int stride; - /* In multiqueue mode, when the number of cpu is equal to the number of - * queue pairs, we let the queue pairs to be private to one cpu by - * setting the affinity hint to eliminate the contention. - */ - if (vi->curr_queue_pairs == 1 || - vi->max_queue_pairs != num_online_cpus()) { + if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) { virtnet_clean_affinity(vi, -1); return; } - i = 0; - for_each_online_cpu(cpu) { - const unsigned long *mask = cpumask_bits(cpumask_of(cpu)); + num_cpu = num_online_cpus(); + stride = max_t(int, num_cpu / vi->curr_queue_pairs, 1); + stragglers = num_cpu >= vi->curr_queue_pairs ? + num_cpu % vi->curr_queue_pairs : + 0; + cpu = cpumask_next(-1, cpu_online_mask); - virtqueue_set_affinity(vi->rq[i].vq, cpumask_of(cpu)); - virtqueue_set_affinity(vi->sq[i].vq, cpumask_of(cpu)); - __netif_set_xps_queue(vi->dev, mask, i, false); - i++; + for (i = 0; i < vi->curr_queue_pairs; i++) { + group_size = stride + (i < stragglers ? 1 : 0); + + for (j = 0; j < group_size; j++) { + cpumask_set_cpu(cpu, mask); + cpu = cpumask_next_wrap(cpu, cpu_online_mask, + nr_cpu_ids, false); + } + virtqueue_set_affinity(vi->rq[i].vq, mask); + virtqueue_set_affinity(vi->sq[i].vq, mask); + __netif_set_xps_queue(vi->dev, cpumask_bits(mask), i, false); + cpumask_clear(mask); } vi->affinity_hint_set = true; + free_cpumask_var(mask); } static int virtnet_cpu_online(unsigned int cpu, struct hlist_node *node) -- 2.18.0.597.ga71716f1ad-goog