Re: Scalability of interface creation and deletion

Le samedi 07 mai 2011 à 09:23 -0700, Ben Greear a écrit :

I wonder if it would be worth having a 'delete me soon'
method to delete interfaces that would not block on the
RCU code.

The controlling programs could use netlink messages to
know exactly when an interface was truly gone.

That should allow some batching in the sync-net logic
too, if user-space code deletes 1000 interfaces very
quickly, for instance...

I suggested in the past to have an extension of batch capabilities, so
that one kthread could have 3 separate lists of devices being destroyed
in //,

This daemon would basically loop on one call to synchronize_rcu(), and
transfert list3 to deletion, list2 to list3, list1 to list2, loop,
eventually releasing RTNL while blocked in synchronize_rcu()

This would need to allow as you suggest an asynchronous deletion method,
or use a callback to wake the process blocked on device delete.

Right now, we hold RTNL for the whole 3 steps process, so we cannot use
any parallelism.