Re: Scalability of interface creation and deletion

Jesse Gross
2011-05-09T17:30:29Z

On Sun, May 8, 2011 at 2:00 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> For example, in the VLAN dismantle phase (ip link del eth0.103)
> we have 3 calls to synchronize_rcu() and one call to rcu_barrier()
>
> [ the 'extra' synchronize_rcu() call comes from unregister_vlan_dev() ]
>
> Maybe with new VLAN model, we could now remove this synchronize_net()
> call from vlan code. Jesse what do you think ?
> Once vlan_group_set_device(grp, vlan_id, NULL) had been called, why
> should we respect one rcu grace period at all, given dev is queued to
> unregister_netdevice_queue() [ which has its own couples of
> synchronize_net() / rcu_barrier() ]

Yes, I agree that the extra call to synchronize_net() provides no
value, though I think that's actually been true for a while.