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| author |   Eric Dumazet <eric.dumazet@gmail.com> | 2009-11-17 05:59:21 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2009-11-18 05:03:11 -0800 |
| commit | e014debecd3ee3832e6476b3a9c948edfcfd1250 (patch) | |
| tree | 9b73836a5dc3c1df92b17037a12bbbfaf5f495d3 /include/linux | |
| parent | ipv4: factorize cache clearing for batched unregister operations (diff) | |
| download | linux-dev-e014debecd3ee3832e6476b3a9c948edfcfd1250.tar.xz linux-dev-e014debecd3ee3832e6476b3a9c948edfcfd1250.zip | |
linkwatch: linkwatch_forget_dev() to speedup device dismantle
Herbert Xu a écrit :
> On Tue, Nov 17, 2009 at 04:26:04AM -0800, David Miller wrote:
>> Really, the link watch stuff is just due for a redesign. I don't
>> think a simple hack is going to cut it this time, sorry Eric :-)
>
> I have no objections against any redesigns, but since the only
> caller of linkwatch_forget_dev runs in process context with the
> RTNL, it could also legally emit those events.
Thanks guys, here an updated version then, before linkwatch surgery ?
In this version, I force the event to be sent synchronously.
[PATCH net-next-2.6] linkwatch: linkwatch_forget_dev() to speedup device dismantle
time ip link del eth3.103 ; time ip link del eth3.104 ; time ip link del eth3.105
real 0m0.266s
user 0m0.000s
sys 0m0.001s
real 0m0.770s
user 0m0.000s
sys 0m0.000s
real 0m1.022s
user 0m0.000s
sys 0m0.000s
One problem of current schem in vlan dismantle phase is the
holding of device done by following chain :
vlan_dev_stop() ->
netif_carrier_off(dev) ->
linkwatch_fire_event(dev) ->
dev_hold() ...
And __linkwatch_run_queue() runs up to one second later...
A generic fix to this problem is to add a linkwatch_forget_dev() method
to unlink the device from the list of watched devices.
dev->link_watch_next becomes dev->link_watch_list (and use a bit more memory),
to be able to unlink device in O(1).
After patch :
time ip link del eth3.103 ; time ip link del eth3.104 ; time ip link del eth3.105
real 0m0.024s
user 0m0.000s
sys 0m0.000s
real 0m0.032s
user 0m0.000s
sys 0m0.001s
real 0m0.033s
user 0m0.000s
sys 0m0.000s
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/netdevice.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index c8fa4627de00..97873e31661c 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -896,7 +896,7 @@ struct net_device { /* device index hash chain */ struct hlist_node index_hlist; - struct net_device *link_watch_next; + struct list_head link_watch_list; /* register/unregister state machine */ enum { NETREG_UNINITIALIZED=0, @@ -1600,6 +1600,7 @@ static inline void dev_hold(struct net_device *dev) */ extern void linkwatch_fire_event(struct net_device *dev); +extern void linkwatch_forget_dev(struct net_device *dev); /** * netif_carrier_ok - test if carrier present |