[TCP]: Limit processing lost_retrans loop to work-to-do cases

This addition of lost_retrans_low to tcp_sock might be
unnecessary, it's not clear how often lost_retrans worker is
executed when there wasn't work to do.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 53296753b0bd..324b4207254a 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1914,6 +1914,8 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
                                 printk(KERN_DEBUG "retrans_out leaked.\n");
                 }
 #endif
+                if (!tp->retrans_out)
+                        tp->lost_retrans_low = tp->snd_nxt;
                 TCP_SKB_CB(skb)->sacked |= TCPCB_RETRANS;
                 tp->retrans_out += tcp_skb_pcount(skb);