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Commit 9d2c27e1 authored by Daniele Lacamera's avatar Daniele Lacamera Committed by David S. Miller
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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: default avatarDaniele Lacamera <root@danielinux.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 58ec3b4d

net/ipv4/tcp_hybla.c

+5 −1
Original line number Original line Diff line number Diff line
@@ -150,7 +150,11 @@ static void hybla_cong_avoid(struct sock *sk, u32 ack, u32 in_flight) 
		ca->snd_cwnd_cents -= 128;

		ca->snd_cwnd_cents -= 128;

		tp->snd_cwnd_cnt = 0;

		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. */

	/* clamp down slowstart cwnd to ssthresh value. */

	if (is_slowstart)

	if (is_slowstart)

		tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);

		tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);