@@ -475,7 +475,15 @@ extern unsigned int tcp_current_mss(struct sock *sk);
/* Bound MSS / TSO packet size with the half of the window */
static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)
{
- if (tp->max_window && pktsize > (tp->max_window >> 1))
+ /* When peer uses tiny windows, there is no use in packetizing
+ * to sub-MSS pieces for the sake of SWS or making sure there
+ * are enough packets in the pipe for fast recovery.
+ *
+ * On the other hand, for extremely large MSS devices, handling
+ * smaller than MSS windows in this way does make sense.
+ */
+ if (tp->max_window >= 512 &&
+ pktsize > (tp->max_window >> 1))
return max(tp->max_window >> 1, 68U - tp->tcp_header_len);
else
return pktsize;