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-rw-r--r--include/linux/tcp.h6
-rw-r--r--include/net/tcp.h11
2 files changed, 12 insertions, 5 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index bc35e4709e8e..a0513210798f 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -197,7 +197,8 @@ struct tcp_sock {
u8 do_early_retrans:1,/* Enable RFC5827 early-retransmit */
syn_data:1, /* SYN includes data */
syn_fastopen:1, /* SYN includes Fast Open option */
- syn_data_acked:1;/* data in SYN is acked by SYN-ACK */
+ syn_data_acked:1,/* data in SYN is acked by SYN-ACK */
+ is_cwnd_limited:1;/* forward progress limited by snd_cwnd? */
u32 tlp_high_seq; /* snd_nxt at the time of TLP retransmit. */
/* RTT measurement */
@@ -209,6 +210,8 @@ struct tcp_sock {
u32 packets_out; /* Packets which are "in flight" */
u32 retrans_out; /* Retransmitted packets out */
+ u32 max_packets_out; /* max packets_out in last window */
+ u32 max_packets_seq; /* right edge of max_packets_out flight */
u16 urg_data; /* Saved octet of OOB data and control flags */
u8 ecn_flags; /* ECN status bits. */
@@ -230,7 +233,6 @@ struct tcp_sock {
u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
u32 snd_cwnd_used;
u32 snd_cwnd_stamp;
- u32 lsnd_pending; /* packets inflight or unsent since last xmit */
u32 prior_cwnd; /* Congestion window at start of Recovery. */
u32 prr_delivered; /* Number of newly delivered packets to
* receiver in Recovery. */
diff --git a/include/net/tcp.h b/include/net/tcp.h
index f5d6ca4a9d28..e80abe4486cb 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -971,8 +971,9 @@ static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
/* We follow the spirit of RFC2861 to validate cwnd but implement a more
* flexible approach. The RFC suggests cwnd should not be raised unless
- * it was fully used previously. But we allow cwnd to grow as long as the
- * application has used half the cwnd.
+ * it was fully used previously. And that's exactly what we do in
+ * congestion avoidance mode. But in slow start we allow cwnd to grow
+ * as long as the application has used half the cwnd.
* Example :
* cwnd is 10 (IW10), but application sends 9 frames.
* We allow cwnd to reach 18 when all frames are ACKed.
@@ -985,7 +986,11 @@ static inline bool tcp_is_cwnd_limited(const struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
- return tp->snd_cwnd < 2 * tp->lsnd_pending;
+ /* If in slow start, ensure cwnd grows to twice what was ACKed. */
+ if (tp->snd_cwnd <= tp->snd_ssthresh)
+ return tp->snd_cwnd < 2 * tp->max_packets_out;
+
+ return tp->is_cwnd_limited;
}
static inline void tcp_check_probe_timer(struct sock *sk)