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[TCP]: Dropped unnecessary skb/sacked accessing in reneging

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SACK reneging can be precalculated to a FLAG in clean_rtx_queue
which has the right skb looked up. This will help a bit in
future because skb->sacked access will be changed eventually,
changing it already won't hurt any.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ilpo Järvinen 2007-12-31 04:49:21 -08:00 committed by David S. Miller
parent 90840defab
commit cadbd0313b
1 changed files with 13 additions and 12 deletions
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25
net/ipv4/tcp_input.c
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@ -105,6 +105,7 @@ int sysctl_tcp_abc __read_mostly;
#define FLAG_SND_UNA_ADVANCED 0x400 /* Snd_una was changed (!= FLAG_DATA_ACKED) */
#define FLAG_DSACKING_ACK 0x800 /* SACK blocks contained D-SACK info */
#define FLAG_NONHEAD_RETRANS_ACKED 0x1000 /* Non-head rexmitted data was ACKed */
#define FLAG_SACK_RENEGING 0x2000 /* snd_una advanced to a sacked seq */
#define FLAG_ACKED (FLAG_DATA_ACKED|FLAG_SYN_ACKED)
#define FLAG_NOT_DUP (FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED)
@ -1918,18 +1919,15 @@ void tcp_enter_loss(struct sock *sk, int how)
tp->frto_counter = 0;
}
static int tcp_check_sack_reneging(struct sock *sk)
/* If ACK arrived pointing to a remembered SACK, it means that our
* remembered SACKs do not reflect real state of receiver i.e.
* receiver _host_ is heavily congested (or buggy).
*
* Do processing similar to RTO timeout.
*/
static int tcp_check_sack_reneging(struct sock *sk, int flag)
{
struct sk_buff *skb;
/* If ACK arrived pointing to a remembered SACK,
* it means that our remembered SACKs do not reflect
* real state of receiver i.e.
* receiver _host_ is heavily congested (or buggy).
* Do processing similar to RTO timeout.
*/
if ((skb = tcp_write_queue_head(sk)) != NULL &&
(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) {
if (flag & FLAG_SACK_RENEGING) {
struct inet_connection_sock *icsk = inet_csk(sk);
NET_INC_STATS_BH(LINUX_MIB_TCPSACKRENEGING);
@ -2515,7 +2513,7 @@ tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag)
tp->prior_ssthresh = 0;
/* B. In all the states check for reneging SACKs. */
if (tp->sacked_out && tcp_check_sack_reneging(sk))
if (tcp_check_sack_reneging(sk, flag))
return;
/* C. Process data loss notification, provided it is valid. */
@ -2852,6 +2850,9 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets)
tcp_clear_all_retrans_hints(tp);
}
if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
flag |= FLAG_SACK_RENEGING;
if (flag & FLAG_ACKED) {
const struct tcp_congestion_ops *ca_ops
= inet_csk(sk)->icsk_ca_ops;