diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 0b88158dd4a7..eb73a1dccf56 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1562,7 +1562,7 @@ static unsigned int tcp_mss_split_point(const struct sock *sk, static inline unsigned int tcp_cwnd_test(const struct tcp_sock *tp, const struct sk_buff *skb) { - u32 in_flight, cwnd; + u32 in_flight, cwnd, halfcwnd; /* Don't be strict about the congestion window for the final FIN. */ if ((TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) && @@ -1571,10 +1571,14 @@ static inline unsigned int tcp_cwnd_test(const struct tcp_sock *tp, in_flight = tcp_packets_in_flight(tp); cwnd = tp->snd_cwnd; - if (in_flight < cwnd) - return (cwnd - in_flight); + if (in_flight >= cwnd) + return 0; - return 0; + /* For better scheduling, ensure we have at least + * 2 GSO packets in flight. + */ + halfcwnd = max(cwnd >> 1, 1U); + return min(halfcwnd, cwnd - in_flight); } /* Initialize TSO state of a skb.