From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754740Ab3AYIha (ORCPT ); Fri, 25 Jan 2013 03:37:30 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:7698 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753493Ab3AYIhN (ORCPT ); Fri, 25 Jan 2013 03:37:13 -0500 X-IronPort-AV: E=Sophos;i="4.84,537,1355068800"; d="scan'208";a="6645782" From: Wanlong Gao To: linux-kernel@vger.kernel.org Cc: Rusty Russell , "Michael S. Tsirkin" , Jason Wang , Eric Dumazet , "David S. Miller" , virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, Wanlong Gao Subject: [PATCH V7 3/3] virtio-net: reset virtqueue affinity when doing cpu hotplug Date: Fri, 25 Jan 2013 16:36:21 +0800 Message-Id: <1359102981-3401-3-git-send-email-gaowanlong@cn.fujitsu.com> X-Mailer: git-send-email 1.8.1 In-Reply-To: <1359102981-3401-1-git-send-email-gaowanlong@cn.fujitsu.com> References: <1359102981-3401-1-git-send-email-gaowanlong@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/01/25 16:35:57, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/01/25 16:35:58, Serialize complete at 2013/01/25 16:35:58 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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: "David S. Miller" Cc: virtualization@lists.linux-foundation.org Cc: netdev@vger.kernel.org Signed-off-by: Wanlong Gao Acked-by: Michael S. Tsirkin --- V6->V7: no change V5->V6: deal with CPU_DOWN_PREPARE separately by just cleaning affinity V4->V5: New method to deal with the cpu hotplug actions (Rusty) drivers/net/virtio_net.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 2f6fe9b..35c00c5 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); @@ -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 { @@ -1067,6 +1071,26 @@ static void virtnet_set_affinity(struct virtnet_info *vi) vi->affinity_hint_set = true; } +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: + case CPU_DEAD: + virtnet_set_affinity(vi); + break; + case CPU_DOWN_PREPARE: + virtnet_clean_affinity(vi, (long)hcpu); + break; + default: + break; + } + return NOTIFY_OK; +} + static void virtnet_get_ringparam(struct net_device *dev, struct ethtool_ringparam *ring) { @@ -1541,6 +1565,13 @@ 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)) { @@ -1587,6 +1618,8 @@ 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