From: Daniele Lacamera Date: Tue, 7 Oct 2008 22:58:17 +0000 (-0700) Subject: tcp: Fix tcp_hybla zero congestion window growth with small rho and large cwnd. X-Git-Tag: v2.6.27~6^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9d2c27e17b7574023b5adb5c6a50d7aaeb915543;p=platform%2Fkernel%2Flinux-stable.git tcp: Fix tcp_hybla zero congestion window growth with small rho and large cwnd. Because of rounding, in certain conditions, i.e. when in congestion avoidance state rho is smaller than 1/128 of the current cwnd, TCP Hybla congestion control starves and the cwnd is kept constant forever. This patch forces an increment by one segment after #send_cwnd calls without increments(newreno behavior). Signed-off-by: Daniele Lacamera Signed-off-by: David S. Miller --- diff --git a/net/ipv4/tcp_hybla.c b/net/ipv4/tcp_hybla.c index bfcbd148a89d..c209e054a634 100644 --- a/net/ipv4/tcp_hybla.c +++ b/net/ipv4/tcp_hybla.c @@ -150,7 +150,11 @@ static void hybla_cong_avoid(struct sock *sk, u32 ack, u32 in_flight) ca->snd_cwnd_cents -= 128; tp->snd_cwnd_cnt = 0; } - + /* check when cwnd has not been incremented for a while */ + if (increment == 0 && odd == 0 && tp->snd_cwnd_cnt >= tp->snd_cwnd) { + tp->snd_cwnd++; + tp->snd_cwnd_cnt = 0; + } /* clamp down slowstart cwnd to ssthresh value. */ if (is_slowstart) tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);