Merge branch 'tcp_bbr-Improving-TCP-BBR-performance-for-WiFi-and-cellular-networks'

Priyaranjan Jha says:

====================
tcp_bbr: Improving TCP BBR performance for WiFi and cellular networks

Ack aggregation is quite prevalent with wifi, cellular and cable modem
link tchnologies, ACK decimation in middleboxes, and common offloading
techniques such as TSO and GRO, at end hosts. Previously, BBR was often
cwnd-limited in the presence of severe ACK aggregation, which resulted in
low throughput due to insufficient data in flight.

To achieve good throughput for wifi and other paths with aggregation, this
patch series implements an ACK aggregation estimator for BBR, which
estimates the maximum recent degree of ACK aggregation and adapts cwnd
based on it. The algorithm is further described by the following
presentation:
https://datatracker.ietf.org/meeting/101/materials/slides-101-iccrg-an-update-on-bbr-work-at-google-00

(1) A preparatory patch, which refactors bbr_target_cwnd for generic
    inflight provisioning.

(2) Implements BBR ack aggregation estimator and adapts cwnd based
    on measured degree of ACK aggregation.
====================

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>