Merge branch 'sched_skb_free_defer'

Eric Dumazet says:

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net_sched: defer skb freeing while changing qdiscs

qdiscs/classes are changed under RTNL protection and often
while blocking BH and root qdisc spinlock.

When lots of skbs need to be dropped, we free
them under these locks causing TX/RX freezes,
and more generally latency spikes.

I saw spikes of 50+ ms on quite fast hardware...

This patch series adds a simple queue protected by RTNL
where skbs can be placed until RTNL is released.

Note that this might also serve in the future for optional
reinjection of packets when a qdisc is replaced.
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Signed-off-by: David S. Miller <davem@davemloft.net>