Merge master.kernel.org:/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog

[linux-2.6] / net / ipv4 / tcp_westwood.c

diff --git a/net/ipv4/tcp_westwood.c b/net/ipv4/tcp_westwood.c
index 12a2cd976e3a06b33edfe08e4d749ac309027506..4247da1384bfb25487b51add257cb8d852ec8327 100644 (file)
--- a/net/ipv4/tcp_westwood.c
+++ b/net/ipv4/tcp_westwood.c
@@ -40,6 +40,7 @@ struct westwood {
        u32    rtt;
        u32    rtt_min;          /* minimum observed RTT */
        u8     first_ack;        /* flag which infers that this is the first ack */
+       u8     reset_rtt_min;    /* Reset RTT min to next RTT sample*/
 };
 
 
@@ -67,6 +68,7 @@ static void tcp_westwood_init(struct sock *sk)
         w->bw_est = 0;
         w->accounted = 0;
         w->cumul_ack = 0;
+       w->reset_rtt_min = 1;
        w->rtt_min = w->rtt = TCP_WESTWOOD_INIT_RTT;
        w->rtt_win_sx = tcp_time_stamp;
        w->snd_una = tcp_sk(sk)->snd_una;
@@ -82,10 +84,16 @@ static inline u32 westwood_do_filter(u32 a, u32 b)
        return (((7 * a) + b) >> 3);
 }
 
-static inline void westwood_filter(struct westwood *w, u32 delta)
+static void westwood_filter(struct westwood *w, u32 delta)
 {
-       w->bw_ns_est = westwood_do_filter(w->bw_ns_est, w->bk / delta);
-       w->bw_est = westwood_do_filter(w->bw_est, w->bw_ns_est);
+       /* If the filter is empty fill it with the first sample of bandwidth  */
+       if (w->bw_ns_est == 0 && w->bw_est == 0) {
+               w->bw_ns_est = w->bk / delta;
+               w->bw_est = w->bw_ns_est;
+       } else {
+               w->bw_ns_est = westwood_do_filter(w->bw_ns_est, w->bk / delta);
+               w->bw_est = westwood_do_filter(w->bw_est, w->bw_ns_est);
+       }
 }
 
 /*
@@ -136,6 +144,16 @@ static void westwood_update_window(struct sock *sk)
        }
 }
 
+static inline void update_rtt_min(struct westwood *w)
+{
+       if (w->reset_rtt_min) {
+               w->rtt_min = w->rtt;
+               w->reset_rtt_min = 0;   
+       } else
+               w->rtt_min = min(w->rtt, w->rtt_min);
+}
+
+
 /*
  * @westwood_fast_bw
  * It is called when we are in fast path. In particular it is called when
@@ -151,7 +169,7 @@ static inline void westwood_fast_bw(struct sock *sk)
 
        w->bk += tp->snd_una - w->snd_una;
        w->snd_una = tp->snd_una;
-       w->rtt_min = min(w->rtt, w->rtt_min);
+       update_rtt_min(w);
 }
 
 /*
@@ -220,12 +238,14 @@ static void tcp_westwood_event(struct sock *sk, enum tcp_ca_event event)
 
        case CA_EVENT_FRTO:
                tp->snd_ssthresh = tcp_westwood_bw_rttmin(sk);
+               /* Update RTT_min when next ack arrives */
+               w->reset_rtt_min = 1;
                break;
 
        case CA_EVENT_SLOW_ACK:
                westwood_update_window(sk);
                w->bk += westwood_acked_count(sk);
-               w->rtt_min = min(w->rtt, w->rtt_min);
+               update_rtt_min(w);
                break;
 
        default: