| Message ID | 1358487121-7956-1-git-send-email-gaowanlong@cn.fujitsu.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On 01/18/2013 01:32 PM, Wanlong Gao wrote: > As Michael mentioned, set affinity and select queue will not work very > well when CPU IDs are not consecutive, this can happen with hot unplug. > Fix this bug by traversal the online CPUs, and create a per cpu variable > to find the mapping from CPU to the preferable virtual-queue. > > Cc: Rusty Russell <rusty@rustcorp.com.au> > Cc: "Michael S. Tsirkin" <mst@redhat.com> > Cc: Jason Wang <jasowang@redhat.com> > Cc: Eric Dumazet <erdnetdev@gmail.com> > Cc: virtualization@lists.linux-foundation.org > Cc: netdev@vger.kernel.org > Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> > --- > V4->V5: > Add get/put_online_cpus to avoid CPUs go up and down during operations (Rusty) > > V3->V4: > move vq_index into virtnet_info (Jason) > change the mapping value when not setting affinity (Jason) > address the comments about select_queue (Rusty) > > drivers/net/virtio_net.c | 60 +++++++++++++++++++++++++++++++++++++++--------- > 1 file changed, 49 insertions(+), 11 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index a6fcf15..440b0eb 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -123,6 +123,9 @@ 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; > }; > > struct skb_vnet_hdr { > @@ -1016,6 +1019,7 @@ static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid) > static void virtnet_set_affinity(struct virtnet_info *vi, bool set) > { > int i; > + int cpu; > > /* 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 > @@ -1029,16 +1033,29 @@ static void virtnet_set_affinity(struct virtnet_info *vi, bool set) > return; > } > > - for (i = 0; i < vi->max_queue_pairs; i++) { > - int cpu = set ? i : -1; > - virtqueue_set_affinity(vi->rq[i].vq, cpu); > - virtqueue_set_affinity(vi->sq[i].vq, cpu); > - } > + if (set) { > + 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; > + i++; > + } > > - if (set) > vi->affinity_hint_set = true; > - else > + } else { > + for(i = 0; i < vi->max_queue_pairs; i++) { > + virtqueue_set_affinity(vi->rq[i].vq, -1); > + virtqueue_set_affinity(vi->sq[i].vq, -1); > + } > + > + i = 0; > + for_each_online_cpu(cpu) > + *per_cpu_ptr(vi->vq_index, cpu) = > + ++i % vi->curr_queue_pairs; > + > vi->affinity_hint_set = false; > + } > } > > static void virtnet_get_ringparam(struct net_device *dev, > @@ -1087,7 +1104,9 @@ static int virtnet_set_channels(struct net_device *dev, > netif_set_real_num_tx_queues(dev, queue_pairs); > netif_set_real_num_rx_queues(dev, queue_pairs); > > + get_online_cpus(); > virtnet_set_affinity(vi, true); > + put_online_cpus(); > } > > return err; > @@ -1127,12 +1146,19 @@ static int virtnet_change_mtu(struct net_device *dev, int new_mtu) > > /* To avoid contending a lock hold by a vcpu who would exit to host, select the > * txq based on the processor id. > - * TODO: handle cpu hotplug. > */ > static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb) > { > - int txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : > - smp_processor_id(); > + 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; > @@ -1248,7 +1274,9 @@ static void virtnet_del_vqs(struct virtnet_info *vi) > { > struct virtio_device *vdev = vi->vdev; > > + get_online_cpus(); > virtnet_set_affinity(vi, false); > + put_online_cpus(); I think the {get|put}_online_cpus() is not necessary here when we are cleaning. > > vdev->config->del_vqs(vdev); > > @@ -1371,7 +1399,10 @@ static int init_vqs(struct virtnet_info *vi) > if (ret) > goto err_free; > > + get_online_cpus(); > virtnet_set_affinity(vi, true); > + put_online_cpus(); > + > return 0; > > err_free: > @@ -1453,6 +1484,10 @@ 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; > + > mutex_init(&vi->config_lock); > vi->config_enable = true; > INIT_WORK(&vi->config_work, virtnet_config_changed_work); > @@ -1476,7 +1511,7 @@ 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_stats; > + goto free_index; > > netif_set_real_num_tx_queues(dev, 1); > netif_set_real_num_rx_queues(dev, 1); > @@ -1520,6 +1555,8 @@ free_recv_bufs: > 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: > @@ -1554,6 +1591,7 @@ static void virtnet_remove(struct virtio_device *vdev) > > flush_work(&vi->config_work); > > + free_percpu(vi->vq_index); > free_percpu(vi->stats); > free_netdev(vi->dev); > } -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 01/18/2013 02:18 PM, Jason Wang wrote: > On 01/18/2013 01:32 PM, Wanlong Gao wrote: >> As Michael mentioned, set affinity and select queue will not work very >> well when CPU IDs are not consecutive, this can happen with hot unplug. >> Fix this bug by traversal the online CPUs, and create a per cpu variable >> to find the mapping from CPU to the preferable virtual-queue. >> >> Cc: Rusty Russell <rusty@rustcorp.com.au> >> Cc: "Michael S. Tsirkin" <mst@redhat.com> >> Cc: Jason Wang <jasowang@redhat.com> >> Cc: Eric Dumazet <erdnetdev@gmail.com> >> Cc: virtualization@lists.linux-foundation.org >> Cc: netdev@vger.kernel.org >> Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> >> --- >> V4->V5: >> Add get/put_online_cpus to avoid CPUs go up and down during operations (Rusty) >> >> V3->V4: >> move vq_index into virtnet_info (Jason) >> change the mapping value when not setting affinity (Jason) >> address the comments about select_queue (Rusty) >> >> drivers/net/virtio_net.c | 60 +++++++++++++++++++++++++++++++++++++++--------- >> 1 file changed, 49 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >> index a6fcf15..440b0eb 100644 >> --- a/drivers/net/virtio_net.c >> +++ b/drivers/net/virtio_net.c >> @@ -123,6 +123,9 @@ 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; >> }; >> >> struct skb_vnet_hdr { >> @@ -1016,6 +1019,7 @@ static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid) >> static void virtnet_set_affinity(struct virtnet_info *vi, bool set) >> { >> int i; >> + int cpu; >> >> /* 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 >> @@ -1029,16 +1033,29 @@ static void virtnet_set_affinity(struct virtnet_info *vi, bool set) >> return; >> } >> >> - for (i = 0; i < vi->max_queue_pairs; i++) { >> - int cpu = set ? i : -1; >> - virtqueue_set_affinity(vi->rq[i].vq, cpu); >> - virtqueue_set_affinity(vi->sq[i].vq, cpu); >> - } >> + if (set) { >> + 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; >> + i++; >> + } >> >> - if (set) >> vi->affinity_hint_set = true; >> - else >> + } else { >> + for(i = 0; i < vi->max_queue_pairs; i++) { >> + virtqueue_set_affinity(vi->rq[i].vq, -1); >> + virtqueue_set_affinity(vi->sq[i].vq, -1); >> + } >> + >> + i = 0; >> + for_each_online_cpu(cpu) >> + *per_cpu_ptr(vi->vq_index, cpu) = >> + ++i % vi->curr_queue_pairs; >> + >> vi->affinity_hint_set = false; >> + } >> } >> >> static void virtnet_get_ringparam(struct net_device *dev, >> @@ -1087,7 +1104,9 @@ static int virtnet_set_channels(struct net_device *dev, >> netif_set_real_num_tx_queues(dev, queue_pairs); >> netif_set_real_num_rx_queues(dev, queue_pairs); >> >> + get_online_cpus(); >> virtnet_set_affinity(vi, true); >> + put_online_cpus(); >> } >> >> return err; >> @@ -1127,12 +1146,19 @@ static int virtnet_change_mtu(struct net_device *dev, int new_mtu) >> >> /* To avoid contending a lock hold by a vcpu who would exit to host, select the >> * txq based on the processor id. >> - * TODO: handle cpu hotplug. >> */ >> static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb) >> { >> - int txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : >> - smp_processor_id(); >> + 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; >> @@ -1248,7 +1274,9 @@ static void virtnet_del_vqs(struct virtnet_info *vi) >> { >> struct virtio_device *vdev = vi->vdev; >> >> + get_online_cpus(); >> virtnet_set_affinity(vi, false); >> + put_online_cpus(); > > I think the {get|put}_online_cpus() is not necessary here when we are > cleaning. When cleaning, we also set the per-cpu variable, is avoiding hot plug or unplug unnecessary? Thanks, Wanlong Gao >> >> vdev->config->del_vqs(vdev); >> >> @@ -1371,7 +1399,10 @@ static int init_vqs(struct virtnet_info *vi) >> if (ret) >> goto err_free; >> >> + get_online_cpus(); >> virtnet_set_affinity(vi, true); >> + put_online_cpus(); >> + >> return 0; >> >> err_free: >> @@ -1453,6 +1484,10 @@ 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; >> + >> mutex_init(&vi->config_lock); >> vi->config_enable = true; >> INIT_WORK(&vi->config_work, virtnet_config_changed_work); >> @@ -1476,7 +1511,7 @@ 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_stats; >> + goto free_index; >> >> netif_set_real_num_tx_queues(dev, 1); >> netif_set_real_num_rx_queues(dev, 1); >> @@ -1520,6 +1555,8 @@ free_recv_bufs: >> 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: >> @@ -1554,6 +1591,7 @@ static void virtnet_remove(struct virtio_device *vdev) >> >> flush_work(&vi->config_work); >> >> + free_percpu(vi->vq_index); >> free_percpu(vi->stats); >> free_netdev(vi->dev); >> } > > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 01/18/2013 02:25 PM, Wanlong Gao wrote: > On 01/18/2013 02:18 PM, Jason Wang wrote: >> On 01/18/2013 01:32 PM, Wanlong Gao wrote: >>> As Michael mentioned, set affinity and select queue will not work very >>> well when CPU IDs are not consecutive, this can happen with hot unplug. >>> Fix this bug by traversal the online CPUs, and create a per cpu variable >>> to find the mapping from CPU to the preferable virtual-queue. >>> >>> Cc: Rusty Russell <rusty@rustcorp.com.au> >>> Cc: "Michael S. Tsirkin" <mst@redhat.com> >>> Cc: Jason Wang <jasowang@redhat.com> >>> Cc: Eric Dumazet <erdnetdev@gmail.com> >>> Cc: virtualization@lists.linux-foundation.org >>> Cc: netdev@vger.kernel.org >>> Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> >>> --- >>> V4->V5: >>> Add get/put_online_cpus to avoid CPUs go up and down during operations (Rusty) >>> >>> V3->V4: >>> move vq_index into virtnet_info (Jason) >>> change the mapping value when not setting affinity (Jason) >>> address the comments about select_queue (Rusty) >>> >>> drivers/net/virtio_net.c | 60 +++++++++++++++++++++++++++++++++++++++--------- >>> 1 file changed, 49 insertions(+), 11 deletions(-) >>> >>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >>> index a6fcf15..440b0eb 100644 >>> --- a/drivers/net/virtio_net.c >>> +++ b/drivers/net/virtio_net.c >>> @@ -123,6 +123,9 @@ 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; >>> }; >>> >>> struct skb_vnet_hdr { >>> @@ -1016,6 +1019,7 @@ static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid) >>> static void virtnet_set_affinity(struct virtnet_info *vi, bool set) >>> { >>> int i; >>> + int cpu; >>> >>> /* 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 >>> @@ -1029,16 +1033,29 @@ static void virtnet_set_affinity(struct virtnet_info *vi, bool set) >>> return; >>> } >>> >>> - for (i = 0; i < vi->max_queue_pairs; i++) { >>> - int cpu = set ? i : -1; >>> - virtqueue_set_affinity(vi->rq[i].vq, cpu); >>> - virtqueue_set_affinity(vi->sq[i].vq, cpu); >>> - } >>> + if (set) { >>> + 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; >>> + i++; >>> + } >>> >>> - if (set) >>> vi->affinity_hint_set = true; >>> - else >>> + } else { >>> + for(i = 0; i < vi->max_queue_pairs; i++) { >>> + virtqueue_set_affinity(vi->rq[i].vq, -1); >>> + virtqueue_set_affinity(vi->sq[i].vq, -1); >>> + } >>> + >>> + i = 0; >>> + for_each_online_cpu(cpu) >>> + *per_cpu_ptr(vi->vq_index, cpu) = >>> + ++i % vi->curr_queue_pairs; >>> + >>> vi->affinity_hint_set = false; >>> + } >>> } >>> >>> static void virtnet_get_ringparam(struct net_device *dev, >>> @@ -1087,7 +1104,9 @@ static int virtnet_set_channels(struct net_device *dev, >>> netif_set_real_num_tx_queues(dev, queue_pairs); >>> netif_set_real_num_rx_queues(dev, queue_pairs); >>> >>> + get_online_cpus(); >>> virtnet_set_affinity(vi, true); >>> + put_online_cpus(); >>> } >>> >>> return err; >>> @@ -1127,12 +1146,19 @@ static int virtnet_change_mtu(struct net_device *dev, int new_mtu) >>> >>> /* To avoid contending a lock hold by a vcpu who would exit to host, select the >>> * txq based on the processor id. >>> - * TODO: handle cpu hotplug. >>> */ >>> static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb) >>> { >>> - int txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : >>> - smp_processor_id(); >>> + 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; >>> @@ -1248,7 +1274,9 @@ static void virtnet_del_vqs(struct virtnet_info *vi) >>> { >>> struct virtio_device *vdev = vi->vdev; >>> >>> + get_online_cpus(); >>> virtnet_set_affinity(vi, false); >>> + put_online_cpus(); >> I think the {get|put}_online_cpus() is not necessary here when we are >> cleaning. > When cleaning, we also set the per-cpu variable, is avoiding hot plug > or unplug unnecessary? We del vqs when: 1) fail to probe the device 2) device removal 3) freeze before suspend In both cases, the device has been stopped. And in 1 and 2 we are about to free the device, the per-cpu won't be used any more. For 3, we will re-initialize the virtqueues during restoring which will call virtnet_set_affinity() which has been protected by {get|put}_online_cpus() below. So looks we could safely remove this. Thanks > > Thanks, > Wanlong Gao > >>> >>> vdev->config->del_vqs(vdev); >>> >>> @@ -1371,7 +1399,10 @@ static int init_vqs(struct virtnet_info *vi) >>> if (ret) >>> goto err_free; >>> >>> + get_online_cpus(); >>> virtnet_set_affinity(vi, true); >>> + put_online_cpus(); >>> + >>> return 0; >>> >>> err_free: >>> @@ -1453,6 +1484,10 @@ 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; >>> + >>> mutex_init(&vi->config_lock); >>> vi->config_enable = true; >>> INIT_WORK(&vi->config_work, virtnet_config_changed_work); >>> @@ -1476,7 +1511,7 @@ 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_stats; >>> + goto free_index; >>> >>> netif_set_real_num_tx_queues(dev, 1); >>> netif_set_real_num_rx_queues(dev, 1); >>> @@ -1520,6 +1555,8 @@ free_recv_bufs: >>> 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: >>> @@ -1554,6 +1591,7 @@ static void virtnet_remove(struct virtio_device *vdev) >>> >>> flush_work(&vi->config_work); >>> >>> + free_percpu(vi->vq_index); >>> free_percpu(vi->stats); >>> free_netdev(vi->dev); >>> } >> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index a6fcf15..440b0eb 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -123,6 +123,9 @@ 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; }; struct skb_vnet_hdr { @@ -1016,6 +1019,7 @@ static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid) static void virtnet_set_affinity(struct virtnet_info *vi, bool set) { int i; + int cpu; /* 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 @@ -1029,16 +1033,29 @@ static void virtnet_set_affinity(struct virtnet_info *vi, bool set) return; } - for (i = 0; i < vi->max_queue_pairs; i++) { - int cpu = set ? i : -1; - virtqueue_set_affinity(vi->rq[i].vq, cpu); - virtqueue_set_affinity(vi->sq[i].vq, cpu); - } + if (set) { + 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; + i++; + } - if (set) vi->affinity_hint_set = true; - else + } else { + for(i = 0; i < vi->max_queue_pairs; i++) { + virtqueue_set_affinity(vi->rq[i].vq, -1); + virtqueue_set_affinity(vi->sq[i].vq, -1); + } + + i = 0; + for_each_online_cpu(cpu) + *per_cpu_ptr(vi->vq_index, cpu) = + ++i % vi->curr_queue_pairs; + vi->affinity_hint_set = false; + } } static void virtnet_get_ringparam(struct net_device *dev, @@ -1087,7 +1104,9 @@ static int virtnet_set_channels(struct net_device *dev, netif_set_real_num_tx_queues(dev, queue_pairs); netif_set_real_num_rx_queues(dev, queue_pairs); + get_online_cpus(); virtnet_set_affinity(vi, true); + put_online_cpus(); } return err; @@ -1127,12 +1146,19 @@ static int virtnet_change_mtu(struct net_device *dev, int new_mtu) /* To avoid contending a lock hold by a vcpu who would exit to host, select the * txq based on the processor id. - * TODO: handle cpu hotplug. */ static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb) { - int txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : - smp_processor_id(); + 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; @@ -1248,7 +1274,9 @@ static void virtnet_del_vqs(struct virtnet_info *vi) { struct virtio_device *vdev = vi->vdev; + get_online_cpus(); virtnet_set_affinity(vi, false); + put_online_cpus(); vdev->config->del_vqs(vdev); @@ -1371,7 +1399,10 @@ static int init_vqs(struct virtnet_info *vi) if (ret) goto err_free; + get_online_cpus(); virtnet_set_affinity(vi, true); + put_online_cpus(); + return 0; err_free: @@ -1453,6 +1484,10 @@ 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; + mutex_init(&vi->config_lock); vi->config_enable = true; INIT_WORK(&vi->config_work, virtnet_config_changed_work); @@ -1476,7 +1511,7 @@ 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_stats; + goto free_index; netif_set_real_num_tx_queues(dev, 1); netif_set_real_num_rx_queues(dev, 1); @@ -1520,6 +1555,8 @@ free_recv_bufs: 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: @@ -1554,6 +1591,7 @@ static void virtnet_remove(struct virtio_device *vdev) flush_work(&vi->config_work); + free_percpu(vi->vq_index); free_percpu(vi->stats); free_netdev(vi->dev); }
As Michael mentioned, set affinity and select queue will not work very well when CPU IDs are not consecutive, this can happen with hot unplug. Fix this bug by traversal the online CPUs, and create a per cpu variable to find the mapping from CPU to the preferable virtual-queue. Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Eric Dumazet <erdnetdev@gmail.com> Cc: virtualization@lists.linux-foundation.org Cc: netdev@vger.kernel.org Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> --- V4->V5: Add get/put_online_cpus to avoid CPUs go up and down during operations (Rusty) V3->V4: move vq_index into virtnet_info (Jason) change the mapping value when not setting affinity (Jason) address the comments about select_queue (Rusty) drivers/net/virtio_net.c | 60 +++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 49 insertions(+), 11 deletions(-)