tcp: enable RACK loss detection to trigger recovery
This patch changes two things:
1. Start fast recovery with RACK in addition to other heuristics
(e.g., DUPACK threshold, FACK). Prior to this change RACK
is enabled to detect losses only after the recovery has
started by other algorithms.
2. Disable TCP early retransmit. RACK subsumes the early retransmit
with the new reordering timer feature. A latter patch in this
series removes the early retransmit code.
Signed-off-by: Yuchung Cheng <[email protected]>
Signed-off-by: Neal Cardwell <[email protected]>
Acked-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 5fb1e75..423438d 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -262,6 +262,9 @@ extern int sysctl_tcp_slow_start_after_idle;
extern int sysctl_tcp_thin_linear_timeouts;
extern int sysctl_tcp_thin_dupack;
extern int sysctl_tcp_early_retrans;
+extern int sysctl_tcp_recovery;
+#define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */
+
extern int sysctl_tcp_limit_output_bytes;
extern int sysctl_tcp_challenge_ack_limit;
extern int sysctl_tcp_min_tso_segs;
@@ -1043,6 +1046,7 @@ static inline void tcp_enable_early_retrans(struct tcp_sock *tp)
tp->do_early_retrans = sysctl_tcp_early_retrans &&
sysctl_tcp_early_retrans < 4 && !sysctl_tcp_thin_dupack &&
+ !(sysctl_tcp_recovery & TCP_RACK_LOSS_DETECTION) &&
net->ipv4.sysctl_tcp_reordering == 3;
}
@@ -1859,13 +1863,6 @@ void tcp_v4_init(void);
void tcp_init(void);
/* tcp_recovery.c */
-
-/* Flags to enable various loss recovery features. See below */
-extern int sysctl_tcp_recovery;
-
-/* Use TCP RACK to detect (some) tail and retransmit losses */
-#define TCP_RACK_LOST_RETRANS 0x1
-
extern void tcp_rack_mark_lost(struct sock *sk, const struct skb_mstamp *now);
extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq,
const struct skb_mstamp *xmit_time,
