[PATCH V3 2/2] virtio-net: reset virtqueue affinity when doing cpu hotplug
From: Wanlong Gao <hidden>
Date: 2013-01-08 10:07:34
Also in:
lkml, netdev
Subsystem:
networking drivers, the rest, virtio net driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, "Michael S. Tsirkin", Jason Wang
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 <redacted> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Eric Dumazet <redacted> Cc: virtualization@lists.linux-foundation.org Cc: netdev@vger.kernel.org Signed-off-by: Wanlong Gao <redacted> --- drivers/net/virtio_net.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index a77f86c..31a25db 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);
@@ -125,6 +126,9 @@ struct virtnet_info { /* Does the affinity hint is set for virtqueues? */ bool affinity_hint_set; + + /* CPU hot plug notifier */ + struct notifier_block nb; }; struct skb_vnet_hdr {
@@ -1057,6 +1061,23 @@ static void virtnet_set_affinity(struct virtnet_info *vi, bool set) } } +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) { + case CPU_ONLINE: + case CPU_ONLINE_FROZEN: + case CPU_DEAD: + case CPU_DEAD_FROZEN: + virtnet_set_affinity(vi, true); + break; + default: + break; + } + return NOTIFY_OK; +} + static void virtnet_get_ringparam(struct net_device *dev, struct ethtool_ringparam *ring) {
@@ -1518,6 +1539,13 @@ 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)) {
@@ -1562,6 +1590,8 @@ 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;
--
1.8.1