AcoSail/kernel_optimize_test
8
0
Fork 0
forked from luck/tmp_suning_uos_patched
Code Pull Requests Activity

tcp: remove tcp_mark_lost_retrans()

Browse Source 
Remove the existing lost retransmit detection because RACK subsumes
it completely. This also stops the overloading the ack_seq field of
the skb control block.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yuchung Cheng 2015-10-16 21:57:43 -07:00 committed by David S. Miller
parent f672258391
commit af82f4e848
3 changed files with 0 additions and 73 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/tcp.h
View File

@ -283,8 +283,6 @@ struct tcp_sock {
int lost_cnt_hint;
u32 retransmit_high; /* L-bits may be on up to this seqno */
u32 lost_retrans_low; /* Sent seq after any rxmit (lowest) */
u32 prior_ssthresh; /* ssthresh saved at recovery start */
u32 high_seq; /* snd_nxt at onset of congestion */

65
net/ipv4/tcp_input.c
View File

@ -1048,70 +1048,6 @@ static bool tcp_is_sackblock_valid(struct tcp_sock *tp, bool is_dsack,
return !before(start_seq, end_seq - tp->max_window);
}
/* Check for lost retransmit. This superb idea is borrowed from "ratehalving".
* Event "B". Later note: FACK people cheated me again 8), we have to account
* for reordering! Ugly, but should help.
*
* Search retransmitted skbs from write_queue that were sent when snd_nxt was
* less than what is now known to be received by the other end (derived from
* highest SACK block). Also calculate the lowest snd_nxt among the remaining
* retransmitted skbs to avoid some costly processing per ACKs.
*/
static void tcp_mark_lost_retrans(struct sock *sk, int *flag)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
int cnt = 0;
u32 new_low_seq = tp->snd_nxt;
u32 received_upto = tcp_highest_sack_seq(tp);
if (!tcp_is_fack(tp) || !tp->retrans_out ||
!after(received_upto, tp->lost_retrans_low) ||
icsk->icsk_ca_state != TCP_CA_Recovery)
return;
tcp_for_write_queue(skb, sk) {
u32 ack_seq = TCP_SKB_CB(skb)->ack_seq;
if (skb == tcp_send_head(sk))
break;
if (cnt == tp->retrans_out)
break;
if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una))
continue;
if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS))
continue;
/* TODO: We would like to get rid of tcp_is_fack(tp) only
* constraint here (see above) but figuring out that at
* least tp->reordering SACK blocks reside between ack_seq
* and received_upto is not easy task to do cheaply with
* the available datastructures.
*
* Whether FACK should check here for tp->reordering segs
* in-between one could argue for either way (it would be
* rather simple to implement as we could count fack_count
* during the walk and do tp->fackets_out - fack_count).
*/
if (after(received_upto, ack_seq)) {
TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
tp->retrans_out -= tcp_skb_pcount(skb);
*flag |= FLAG_LOST_RETRANS;
tcp_skb_mark_lost_uncond_verify(tp, skb);
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPLOSTRETRANSMIT);
} else {
if (before(ack_seq, new_low_seq))
new_low_seq = ack_seq;
cnt += tcp_skb_pcount(skb);
}
}
if (tp->retrans_out)
tp->lost_retrans_low = new_low_seq;
}
static bool tcp_check_dsack(struct sock *sk, const struct sk_buff *ack_skb,
struct tcp_sack_block_wire *sp, int num_sacks,
u32 prior_snd_una)
@ -1838,7 +1774,6 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
((inet_csk(sk)->icsk_ca_state != TCP_CA_Loss) || tp->undo_marker))
tcp_update_reordering(sk, tp->fackets_out - state->reord, 0);
tcp_mark_lost_retrans(sk, &state->flag);
tcp_verify_left_out(tp);
out:

6
net/ipv4/tcp_output.c
View File

@ -2655,8 +2655,6 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
net_dbg_ratelimited("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);
@ -2664,10 +2662,6 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
if (!tp->retrans_stamp)
tp->retrans_stamp = tcp_skb_timestamp(skb);
/* snd_nxt is stored to detect loss of retransmitted segment,
* see tcp_input.c tcp_sacktag_write_queue().
*/
TCP_SKB_CB(skb)->ack_seq = tp->snd_nxt;
} else if (err != -EBUSY) {
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPRETRANSFAIL);
}