From 99c4a26a159b28fa46a3e746a9b41b297e73d261 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Wed, 18 Mar 2015 22:52:33 -0400 Subject: net: Fix high overhead of vlan sub-device teardown. When a networking device is taken down that has a non-trivial number of VLAN devices configured under it, we eat a full synchronize_net() for every such VLAN device. This is because of the call chain: NETDEV_DOWN notifier --> vlan_device_event() --> dev_change_flags() --> __dev_change_flags() --> __dev_close() --> __dev_close_many() --> dev_deactivate_many() --> synchronize_net() This is kind of rediculous because we already have infrastructure for batching doing operation X to a list of net devices so that we only incur one sync. So make use of that by exporting dev_close_many() and adjusting it's interfaace so that the caller can fully manage the batch list. Use this in vlan_device_event() and all the overhead goes away. Reported-by: Salam Noureddine Signed-off-by: David S. Miller --- net/8021q/vlan.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'net/8021q') diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c index 64c6bed4a3d3..98a30a5b8664 100644 --- a/net/8021q/vlan.c +++ b/net/8021q/vlan.c @@ -413,7 +413,10 @@ static int vlan_device_event(struct notifier_block *unused, unsigned long event, vlan_transfer_features(dev, vlandev); break; - case NETDEV_DOWN: + case NETDEV_DOWN: { + struct net_device *tmp; + LIST_HEAD(close_list); + if (dev->features & NETIF_F_HW_VLAN_CTAG_FILTER) vlan_vid_del(dev, htons(ETH_P_8021Q), 0); @@ -425,11 +428,18 @@ static int vlan_device_event(struct notifier_block *unused, unsigned long event, vlan = vlan_dev_priv(vlandev); if (!(vlan->flags & VLAN_FLAG_LOOSE_BINDING)) - dev_change_flags(vlandev, flgs & ~IFF_UP); + list_add(&vlandev->close_list, &close_list); + } + + dev_close_many(&close_list, false); + + list_for_each_entry_safe(vlandev, tmp, &close_list, close_list) { netif_stacked_transfer_operstate(dev, vlandev); + list_del_init(&vlandev->close_list); } + list_del(&close_list); break; - + } case NETDEV_UP: /* Put all VLANs for this dev in the up state too. */ vlan_group_for_each_dev(grp, i, vlandev) { -- cgit