Merge branch 'net_sched-allow-use-of-hrtimer-slack'

Eric Dumazet says:

====================
net_sched: allow use of hrtimer slack

Packet schedulers have used hrtimers with exact expiry times.

Some of them can afford having a slack, in order to reduce
the number of timer interrupts and feed bigger batches
to increase efficiency.

FQ for example does not care if throttled packets are
sent with an additional (small) delay.

Original observation of having maybe too many interrupts
was made by Willem de Bruijn.

v2: added strict netlink checking (Jakub Kicinski)
====================

Signed-off-by: David S. Miller <davem@davemloft.net>