revalidator: Replace ukey->mark with dump_seq.

Rather than setting and resetting the 'mark' field in the ukey, this
patch introduces a seq to track whether a flow has been seen during the
most recent dump. This tidies the code and simplifies the logic for
detecting when flows are duplicated from the datapath.

Signed-off-by: Joe Stringer <joestringer@nicira.com>
Acked-by: Ethan Jackson <ethan@nicira.com>
netdev: netdev_send accepts multiple packets

The netdev_send function has been modified to accept multiple packets, to
allow netdev providers to amortize locking and queuing costs.
This is especially true for netdev-dpdk.

Later commits exploit the new API.

Signed-off-by: Daniele Di Proietto <ddiproietto@vmware.com>
dpif-netdev: batch packet processing

This change in dpif-netdev allows faster packet processing for devices which
implement batching (netdev-dpdk currently).

Signed-off-by: Daniele Di Proietto <ddiproietto@vmware.com>
move the rdlock out of the loop.
refactor the dpif netdev batching stuff.
batch the classifier lookup function
prefetch subtables