Commit e636f8b0 authored by Yuchung Cheng's avatar Yuchung Cheng Committed by David S. Miller

tcp: new helper for RACK to detect loss

Create a new helper tcp_rack_detect_loss to prepare the upcoming
RACK reordering timer patch.
Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent db8da6bb
......@@ -1863,8 +1863,7 @@ extern int sysctl_tcp_recovery;
/* Use TCP RACK to detect (some) tail and retransmit losses */
#define TCP_RACK_LOST_RETRANS 0x1
extern int tcp_rack_mark_lost(struct sock *sk);
extern void tcp_rack_mark_lost(struct sock *sk);
extern void tcp_rack_advance(struct tcp_sock *tp,
const struct skb_mstamp *xmit_time, u8 sacked);
......
......@@ -2865,11 +2865,15 @@ static void tcp_fastretrans_alert(struct sock *sk, const int acked,
}
/* Use RACK to detect loss */
if (sysctl_tcp_recovery & TCP_RACK_LOST_RETRANS &&
tcp_rack_mark_lost(sk)) {
if (sysctl_tcp_recovery & TCP_RACK_LOST_RETRANS) {
u32 prior_retrans = tp->retrans_out;
tcp_rack_mark_lost(sk);
if (prior_retrans > tp->retrans_out) {
flag |= FLAG_LOST_RETRANS;
*ack_flag |= FLAG_LOST_RETRANS;
}
}
/* E. Process state. */
switch (icsk->icsk_ca_state) {
......
......@@ -32,17 +32,11 @@ static void tcp_rack_mark_skb_lost(struct sock *sk, struct sk_buff *skb)
* The current version is only used after recovery starts but can be
* easily extended to detect the first loss.
*/
int tcp_rack_mark_lost(struct sock *sk)
static void tcp_rack_detect_loss(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
u32 reo_wnd, prior_retrans = tp->retrans_out;
if (inet_csk(sk)->icsk_ca_state < TCP_CA_Recovery || !tp->rack.advanced)
return 0;
/* Reset the advanced flag to avoid unnecessary queue scanning */
tp->rack.advanced = 0;
u32 reo_wnd;
/* To be more reordering resilient, allow min_rtt/4 settling delay
* (lower-bounded to 1000uS). We use min_rtt instead of the smoothed
......@@ -82,7 +76,17 @@ int tcp_rack_mark_lost(struct sock *sk)
break;
}
}
return prior_retrans - tp->retrans_out;
}
void tcp_rack_mark_lost(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
if (inet_csk(sk)->icsk_ca_state < TCP_CA_Recovery || !tp->rack.advanced)
return;
/* Reset the advanced flag to avoid unnecessary queue scanning */
tp->rack.advanced = 0;
tcp_rack_detect_loss(sk);
}
/* Record the most recently (re)sent time among the (s)acked packets */
......
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