diff options
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/tcp_input.c | 64 |
1 files changed, 32 insertions, 32 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 3ab0c75..38589e4 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2700,6 +2700,38 @@ static bool tcp_try_undo_loss(struct sock *sk) return false; } +/* This function implements the PRR algorithm, specifcally the PRR-SSRB + * (proportional rate reduction with slow start reduction bound) as described in + * http://www.ietf.org/id/draft-mathis-tcpm-proportional-rate-reduction-01.txt. + * It computes the number of packets to send (sndcnt) based on packets newly + * delivered: + * 1) If the packets in flight is larger than ssthresh, PRR spreads the + * cwnd reductions across a full RTT. + * 2) If packets in flight is lower than ssthresh (such as due to excess + * losses and/or application stalls), do not perform any further cwnd + * reductions, but instead slow start up to ssthresh. + */ +static void tcp_update_cwnd_in_recovery(struct sock *sk, int newly_acked_sacked, + int fast_rexmit, int flag) +{ + struct tcp_sock *tp = tcp_sk(sk); + int sndcnt = 0; + int delta = tp->snd_ssthresh - tcp_packets_in_flight(tp); + + if (tcp_packets_in_flight(tp) > tp->snd_ssthresh) { + u64 dividend = (u64)tp->snd_ssthresh * tp->prr_delivered + + tp->prior_cwnd - 1; + sndcnt = div_u64(dividend, tp->prior_cwnd) - tp->prr_out; + } else { + sndcnt = min_t(int, delta, + max_t(int, tp->prr_delivered - tp->prr_out, + newly_acked_sacked) + 1); + } + + sndcnt = max(sndcnt, (fast_rexmit ? 1 : 0)); + tp->snd_cwnd = tcp_packets_in_flight(tp) + sndcnt; +} + static inline void tcp_complete_cwr(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); @@ -2854,38 +2886,6 @@ void tcp_simple_retransmit(struct sock *sk) } EXPORT_SYMBOL(tcp_simple_retransmit); -/* This function implements the PRR algorithm, specifcally the PRR-SSRB - * (proportional rate reduction with slow start reduction bound) as described in - * http://www.ietf.org/id/draft-mathis-tcpm-proportional-rate-reduction-01.txt. - * It computes the number of packets to send (sndcnt) based on packets newly - * delivered: - * 1) If the packets in flight is larger than ssthresh, PRR spreads the - * cwnd reductions across a full RTT. - * 2) If packets in flight is lower than ssthresh (such as due to excess - * losses and/or application stalls), do not perform any further cwnd - * reductions, but instead slow start up to ssthresh. - */ -static void tcp_update_cwnd_in_recovery(struct sock *sk, int newly_acked_sacked, - int fast_rexmit, int flag) -{ - struct tcp_sock *tp = tcp_sk(sk); - int sndcnt = 0; - int delta = tp->snd_ssthresh - tcp_packets_in_flight(tp); - - if (tcp_packets_in_flight(tp) > tp->snd_ssthresh) { - u64 dividend = (u64)tp->snd_ssthresh * tp->prr_delivered + - tp->prior_cwnd - 1; - sndcnt = div_u64(dividend, tp->prior_cwnd) - tp->prr_out; - } else { - sndcnt = min_t(int, delta, - max_t(int, tp->prr_delivered - tp->prr_out, - newly_acked_sacked) + 1); - } - - sndcnt = max(sndcnt, (fast_rexmit ? 1 : 0)); - tp->snd_cwnd = tcp_packets_in_flight(tp) + sndcnt; -} - static void tcp_enter_recovery(struct sock *sk, bool ece_ack) { struct tcp_sock *tp = tcp_sk(sk); |