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| author | David S. Miller <davem@davemloft.net> | 2015-03-18 22:52:33 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-03-18 22:52:56 -0400 |
| commit | 99c4a26a159b28fa46a3e746a9b41b297e73d261 (patch) | |
| tree | 38f5c5d424b7596b77e1f40d7c5f1ce33cfa115e /net/8021q | |
| parent | 738e6d30d392fb75933a5eb4b481811598038786 (diff) | |
| download | linux-99c4a26a159b28fa46a3e746a9b41b297e73d261.tar.gz linux-99c4a26a159b28fa46a3e746a9b41b297e73d261.tar.bz2 linux-99c4a26a159b28fa46a3e746a9b41b297e73d261.zip | |
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.c | 16 |
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) { |