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author | Neal Cardwell <ncardwell@google.com> | 2016-01-11 18:42:43 (GMT) |
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committer | David S. Miller <davem@davemloft.net> | 2016-01-11 22:25:16 (GMT) |
commit | 83d15e70c4d8909d722c0d64747d8fb42e38a48f (patch) | |
tree | 2b3b91b39e4c5e53fa413175b2e598ceab45cbae /net/sched/cls_flower.c | |
parent | 649621e3d54439ae232d726d7beef295d3887a68 (diff) | |
download | linux-83d15e70c4d8909d722c0d64747d8fb42e38a48f.tar.xz |
tcp_yeah: don't set ssthresh below 2
For tcp_yeah, use an ssthresh floor of 2, the same floor used by Reno
and CUBIC, per RFC 5681 (equation 4).
tcp_yeah_ssthresh() was sometimes returning a 0 or negative ssthresh
value if the intended reduction is as big or bigger than the current
cwnd. Congestion control modules should never return a zero or
negative ssthresh. A zero ssthresh generally results in a zero cwnd,
causing the connection to stall. A negative ssthresh value will be
interpreted as a u32 and will set a target cwnd for PRR near 4
billion.
Oleksandr Natalenko reported that a system using tcp_yeah with ECN
could see a warning about a prior_cwnd of 0 in
tcp_cwnd_reduction(). Testing verified that this was due to
tcp_yeah_ssthresh() misbehaving in this way.
Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/cls_flower.c')
0 files changed, 0 insertions, 0 deletions