diff options
| -rw-r--r-- | net/ipv4/tcp_input.c | 63 |
1 files changed, 39 insertions, 24 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 125b4517f36..03f5ede8722 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2461,6 +2461,44 @@ static int tcp_time_to_recover(struct sock *sk) return 0; } +/* New heuristics: it is possible only after we switched to restart timer + * each time when something is ACKed. Hence, we can detect timed out packets + * during fast retransmit without falling to slow start. + * + * Usefulness of this as is very questionable, since we should know which of + * the segments is the next to timeout which is relatively expensive to find + * in general case unless we add some data structure just for that. The + * current approach certainly won't find the right one too often and when it + * finally does find _something_ it usually marks large part of the window + * right away (because a retransmission with a larger timestamp blocks the + * loop from advancing). -ij + */ +static void tcp_timeout_skbs(struct sock *sk) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct sk_buff *skb; + + if (!tcp_is_fack(tp) || !tcp_head_timedout(sk)) + return; + + skb = tp->scoreboard_skb_hint; + if (tp->scoreboard_skb_hint == NULL) + skb = tcp_write_queue_head(sk); + + tcp_for_write_queue_from(skb, sk) { + if (skb == tcp_send_head(sk)) + break; + if (!tcp_skb_timedout(sk, skb)) + break; + + tcp_skb_mark_lost(tp, skb); + } + + tp->scoreboard_skb_hint = skb; + + tcp_verify_left_out(tp); +} + /* Mark head of queue up as lost. With RFC3517 SACK, the packets is * is against sacked "cnt", otherwise it's against facked "cnt" */ @@ -2533,30 +2571,7 @@ static void tcp_update_scoreboard(struct sock *sk, int fast_rexmit) tcp_mark_head_lost(sk, sacked_upto); } - /* New heuristics: it is possible only after we switched - * to restart timer each time when something is ACKed. - * Hence, we can detect timed out packets during fast - * retransmit without falling to slow start. - */ - if (tcp_is_fack(tp) && tcp_head_timedout(sk)) { - struct sk_buff *skb; - - skb = tp->scoreboard_skb_hint ? tp->scoreboard_skb_hint - : tcp_write_queue_head(sk); - - tcp_for_write_queue_from(skb, sk) { - if (skb == tcp_send_head(sk)) - break; - if (!tcp_skb_timedout(sk, skb)) - break; - - tcp_skb_mark_lost(tp, skb); - } - - tp->scoreboard_skb_hint = skb; - - tcp_verify_left_out(tp); - } + tcp_timeout_skbs(sk); } /* CWND moderation, preventing bursts due to too big ACKs |