From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wanlong Gao Subject: [PATCH V3 2/2] virtio-net: reset virtqueue affinity when doing cpu hotplug Date: Tue, 8 Jan 2013 18:07:40 +0800 Message-ID: <1357639660-6660-2-git-send-email-gaowanlong@cn.fujitsu.com> References: <1357639660-6660-1-git-send-email-gaowanlong@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "Michael S. Tsirkin" , netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, Eric Dumazet To: linux-kernel@vger.kernel.org Return-path: In-Reply-To: <1357639660-6660-1-git-send-email-gaowanlong@cn.fujitsu.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: netdev.vger.kernel.org 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 Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Eric Dumazet Cc: virtualization@lists.linux-foundation.org Cc: netdev@vger.kernel.org Signed-off-by: Wanlong Gao --- 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 #include #include +#include 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