| Message ID | 1358487121-7956-2-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: > Add a cpu notifier to virtio-net, so that we can reset the > virtqueue affinity if the cpu hotplug happens. It improve > the performance through enabling or disabling the virtqueue > affinity after doing cpu hotplug. > > 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: > New method to deal with the cpu hotplug actions (Rusty) > > drivers/net/virtio_net.c | 50 ++++++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 44 insertions(+), 6 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 440b0eb..061f2c5 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -26,6 +26,7 @@ > #include <linux/scatterlist.h> > #include <linux/if_vlan.h> > #include <linux/slab.h> > +#include <linux/cpu.h> > > static int napi_weight = 128; > module_param(napi_weight, int, 0444); > @@ -126,6 +127,9 @@ struct virtnet_info { > > /* Per-cpu variable to show the mapping from CPU to virtqueue */ > int __percpu *vq_index; > + > + /* CPU hot plug notifier */ > + struct notifier_block nb; > }; > > struct skb_vnet_hdr { > @@ -1016,7 +1020,7 @@ static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid) > return 0; > } > > -static void virtnet_set_affinity(struct virtnet_info *vi, bool set) > +static void virtnet_set_affinity(struct virtnet_info *vi, bool set, long hcpu) > { > int i; > int cpu; > @@ -1026,7 +1030,8 @@ static void virtnet_set_affinity(struct virtnet_info *vi, bool set) > * setting the affinity hint to eliminate the contention. > */ > if ((vi->curr_queue_pairs == 1 || > - vi->max_queue_pairs != num_online_cpus()) && set) { > + vi->max_queue_pairs != num_online_cpus() - ((hcpu == -1) ? 0 : 1)) > + && set) { > if (vi->affinity_hint_set) > set = false; > else This make complex the this function. How about introduce another function that just clean the affinity of cpu during CPU_DOWN_PREPARE. Then we could get a simpler virtnet_set_affinity() called in CPU_DEAD like you previous version? > @@ -1036,6 +1041,8 @@ static void virtnet_set_affinity(struct virtnet_info *vi, bool set) > if (set) { > i = 0; > for_each_online_cpu(cpu) { > + if (cpu == hcpu) > + continue; > virtqueue_set_affinity(vi->rq[i].vq, cpu); > virtqueue_set_affinity(vi->sq[i].vq, cpu); > *per_cpu_ptr(vi->vq_index, cpu) = i; > @@ -1050,14 +1057,36 @@ static void virtnet_set_affinity(struct virtnet_info *vi, bool set) > } > > i = 0; > - for_each_online_cpu(cpu) > + for_each_online_cpu(cpu) { > + if (cpu == hcpu) > + continue; > *per_cpu_ptr(vi->vq_index, cpu) = > ++i % vi->curr_queue_pairs; > + } > > vi->affinity_hint_set = false; > } > } > > +static int virtnet_cpu_callback(struct notifier_block *nfb, > + unsigned long action, void *hcpu) > +{ > + struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb); > + > + switch(action & ~CPU_TASKS_FROZEN) { > + case CPU_ONLINE: > + case CPU_DOWN_FAILED: > + virtnet_set_affinity(vi, true, -1); > + break; > + case CPU_DOWN_PREPARE: > + virtnet_set_affinity(vi, true, (long)hcpu); > + break; > + default: > + break; > + } > + return NOTIFY_OK; > +} > + > static void virtnet_get_ringparam(struct net_device *dev, > struct ethtool_ringparam *ring) > { > @@ -1105,7 +1134,7 @@ static int virtnet_set_channels(struct net_device *dev, > netif_set_real_num_rx_queues(dev, queue_pairs); > > get_online_cpus(); > - virtnet_set_affinity(vi, true); > + virtnet_set_affinity(vi, true, -1); > put_online_cpus(); > } > > @@ -1275,7 +1304,7 @@ static void virtnet_del_vqs(struct virtnet_info *vi) > struct virtio_device *vdev = vi->vdev; > > get_online_cpus(); > - virtnet_set_affinity(vi, false); > + virtnet_set_affinity(vi, false, -1); > put_online_cpus(); > > vdev->config->del_vqs(vdev); > @@ -1400,7 +1429,7 @@ static int init_vqs(struct virtnet_info *vi) > goto err_free; > > get_online_cpus(); > - virtnet_set_affinity(vi, true); > + virtnet_set_affinity(vi, true, -1); > put_online_cpus(); > > return 0; > @@ -1534,6 +1563,13 @@ static int virtnet_probe(struct virtio_device *vdev) > } > } > > + vi->nb.notifier_call = &virtnet_cpu_callback; > + err = register_hotcpu_notifier(&vi->nb); > + if (err) { > + pr_debug("virtio_net: registering cpu notifier failed\n"); > + goto free_recv_bufs; > + } > + > /* Assume link up if device can't report link status, > otherwise get link status from config. */ > if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) { > @@ -1580,6 +1616,8 @@ static void virtnet_remove(struct virtio_device *vdev) > { > struct virtnet_info *vi = vdev->priv; > > + unregister_hotcpu_notifier(&vi->nb); > + > /* Prevent config work handler from accessing the device. */ > mutex_lock(&vi->config_lock); > vi->config_enable = false; -- 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 440b0eb..061f2c5 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -26,6 +26,7 @@ #include <linux/scatterlist.h> #include <linux/if_vlan.h> #include <linux/slab.h> +#include <linux/cpu.h> static int napi_weight = 128; module_param(napi_weight, int, 0444); @@ -126,6 +127,9 @@ struct virtnet_info { /* Per-cpu variable to show the mapping from CPU to virtqueue */ int __percpu *vq_index; + + /* CPU hot plug notifier */ + struct notifier_block nb; }; struct skb_vnet_hdr { @@ -1016,7 +1020,7 @@ static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid) return 0; } -static void virtnet_set_affinity(struct virtnet_info *vi, bool set) +static void virtnet_set_affinity(struct virtnet_info *vi, bool set, long hcpu) { int i; int cpu; @@ -1026,7 +1030,8 @@ static void virtnet_set_affinity(struct virtnet_info *vi, bool set) * setting the affinity hint to eliminate the contention. */ if ((vi->curr_queue_pairs == 1 || - vi->max_queue_pairs != num_online_cpus()) && set) { + vi->max_queue_pairs != num_online_cpus() - ((hcpu == -1) ? 0 : 1)) + && set) { if (vi->affinity_hint_set) set = false; else @@ -1036,6 +1041,8 @@ static void virtnet_set_affinity(struct virtnet_info *vi, bool set) if (set) { i = 0; for_each_online_cpu(cpu) { + if (cpu == hcpu) + continue; virtqueue_set_affinity(vi->rq[i].vq, cpu); virtqueue_set_affinity(vi->sq[i].vq, cpu); *per_cpu_ptr(vi->vq_index, cpu) = i; @@ -1050,14 +1057,36 @@ static void virtnet_set_affinity(struct virtnet_info *vi, bool set) } i = 0; - for_each_online_cpu(cpu) + for_each_online_cpu(cpu) { + if (cpu == hcpu) + continue; *per_cpu_ptr(vi->vq_index, cpu) = ++i % vi->curr_queue_pairs; + } vi->affinity_hint_set = false; } } +static int virtnet_cpu_callback(struct notifier_block *nfb, + unsigned long action, void *hcpu) +{ + struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb); + + switch(action & ~CPU_TASKS_FROZEN) { + case CPU_ONLINE: + case CPU_DOWN_FAILED: + virtnet_set_affinity(vi, true, -1); + break; + case CPU_DOWN_PREPARE: + virtnet_set_affinity(vi, true, (long)hcpu); + break; + default: + break; + } + return NOTIFY_OK; +} + static void virtnet_get_ringparam(struct net_device *dev, struct ethtool_ringparam *ring) { @@ -1105,7 +1134,7 @@ static int virtnet_set_channels(struct net_device *dev, netif_set_real_num_rx_queues(dev, queue_pairs); get_online_cpus(); - virtnet_set_affinity(vi, true); + virtnet_set_affinity(vi, true, -1); put_online_cpus(); } @@ -1275,7 +1304,7 @@ static void virtnet_del_vqs(struct virtnet_info *vi) struct virtio_device *vdev = vi->vdev; get_online_cpus(); - virtnet_set_affinity(vi, false); + virtnet_set_affinity(vi, false, -1); put_online_cpus(); vdev->config->del_vqs(vdev); @@ -1400,7 +1429,7 @@ static int init_vqs(struct virtnet_info *vi) goto err_free; get_online_cpus(); - virtnet_set_affinity(vi, true); + virtnet_set_affinity(vi, true, -1); put_online_cpus(); return 0; @@ -1534,6 +1563,13 @@ static int virtnet_probe(struct virtio_device *vdev) } } + vi->nb.notifier_call = &virtnet_cpu_callback; + err = register_hotcpu_notifier(&vi->nb); + if (err) { + pr_debug("virtio_net: registering cpu notifier failed\n"); + goto free_recv_bufs; + } + /* Assume link up if device can't report link status, otherwise get link status from config. */ if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) { @@ -1580,6 +1616,8 @@ static void virtnet_remove(struct virtio_device *vdev) { struct virtnet_info *vi = vdev->priv; + unregister_hotcpu_notifier(&vi->nb); + /* Prevent config work handler from accessing the device. */ mutex_lock(&vi->config_lock); vi->config_enable = false;
Add a cpu notifier to virtio-net, so that we can reset the virtqueue affinity if the cpu hotplug happens. It improve the performance through enabling or disabling the virtqueue affinity after doing cpu hotplug. 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: New method to deal with the cpu hotplug actions (Rusty) drivers/net/virtio_net.c | 50 ++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 44 insertions(+), 6 deletions(-)