diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index c6b9f92..c072f88 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -333,6 +333,8 @@
 
 	struct tcp_sack_block_wire recv_sack_cache[4];
 
+	u32	highest_sack;	/* Start seq of globally highest revd SACK (valid only in slowpath) */
+
 	/* from STCP, retrans queue hinting */
 	struct sk_buff* lost_skb_hint;
 
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index f893e90..813f204 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -979,8 +979,10 @@
 	int i;
 	int first_sack_index;
 
-	if (!tp->sacked_out)
+	if (!tp->sacked_out) {
 		tp->fackets_out = 0;
+		tp->highest_sack = tp->snd_una;
+	}
 	prior_fackets = tp->fackets_out;
 
 	/* Check for D-SACK. */
@@ -1217,6 +1219,10 @@
 
 				if (fack_count > tp->fackets_out)
 					tp->fackets_out = fack_count;
+
+				if (after(TCP_SKB_CB(skb)->seq,
+				    tp->highest_sack))
+					tp->highest_sack = TCP_SKB_CB(skb)->seq;
 			} else {
 				if (dup_sack && (sacked&TCPCB_RETRANS))
 					reord = min(fack_count, reord);