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authorDavid S. Miller <davem@davemloft.net>2015-03-18 22:52:33 -0400
committerDavid S. Miller <davem@davemloft.net>2015-03-18 22:52:56 -0400
commit99c4a26a159b28fa46a3e746a9b41b297e73d261 (patch)
tree38f5c5d424b7596b77e1f40d7c5f1ce33cfa115e /net/8021q
parent738e6d30d392fb75933a5eb4b481811598038786 (diff)
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 <noureddine@arista.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/8021q')
-rw-r--r--net/8021q/vlan.c16
1 files changed, 13 insertions, 3 deletions
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) {

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