tcp: allow congestion control module to request TSO skb segment count
authorNeal Cardwell <ncardwell@google.com>
Tue, 20 Sep 2016 03:39:17 +0000 (23:39 -0400)
committerDavid S. Miller <davem@davemloft.net>
Wed, 21 Sep 2016 04:23:00 +0000 (00:23 -0400)
commited6e7268b930e0a9a65d895d368eac79a438d992
tree4dddd837b12a0691140285fac90c1bac9ff5f82b
parenteb8329e0a04db0061f714f033b4454326ba147f4
tcp: allow congestion control module to request TSO skb segment count

Add the tso_segs_goal() function in tcp_congestion_ops to allow the
congestion control module to specify the number of segments that
should be in a TSO skb sent by tcp_write_xmit() and
tcp_xmit_retransmit_queue(). The congestion control module can either
request a particular number of segments in TSO skb that we transmit,
or return 0 if it doesn't care.

This allows the upcoming BBR congestion control module to select small
TSO skb sizes if the module detects that the bottleneck bandwidth is
very low, or that the connection is policed to a low rate.

Signed-off-by: Van Jacobson <vanj@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Nandita Dukkipati <nanditad@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
include/net/tcp.h
net/ipv4/tcp_output.c