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| author | David S. Miller <davem@davemloft.net> | 2015-03-19 05:52:33 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-03-19 05:52:56 +0300 |
| commit | 99c4a26a159b28fa46a3e746a9b41b297e73d261 (patch) | |
| tree | 38f5c5d424b7596b77e1f40d7c5f1ce33cfa115e /net/core | |
| parent | 738e6d30d392fb75933a5eb4b481811598038786 (diff) | |
| download | linux-99c4a26a159b28fa46a3e746a9b41b297e73d261.tar.xz | |
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/core')
| -rw-r--r-- | net/core/dev.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index a1f24151db5b..5d43e010ef87 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1385,7 +1385,7 @@ static int __dev_close(struct net_device *dev) return retval; } -static int dev_close_many(struct list_head *head) +int dev_close_many(struct list_head *head, bool unlink) { struct net_device *dev, *tmp; @@ -1399,11 +1399,13 @@ static int dev_close_many(struct list_head *head) list_for_each_entry_safe(dev, tmp, head, close_list) { rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING, GFP_KERNEL); call_netdevice_notifiers(NETDEV_DOWN, dev); - list_del_init(&dev->close_list); + if (unlink) + list_del_init(&dev->close_list); } return 0; } +EXPORT_SYMBOL(dev_close_many); /** * dev_close - shutdown an interface. @@ -1420,7 +1422,7 @@ int dev_close(struct net_device *dev) LIST_HEAD(single); list_add(&dev->close_list, &single); - dev_close_many(&single); + dev_close_many(&single, true); list_del(&single); } return 0; @@ -5986,7 +5988,7 @@ static void rollback_registered_many(struct list_head *head) /* If device is running, close it first. */ list_for_each_entry(dev, head, unreg_list) list_add_tail(&dev->close_list, &close_head); - dev_close_many(&close_head); + dev_close_many(&close_head, true); list_for_each_entry(dev, head, unreg_list) { /* And unlink it from device chain. */ |