tcp: xps: fix reordering issues

commit 3853b58 ("xps: Improvements in TX queue selection") introduced ooo_okay flag, but the condition to set it is slightly wrong. In our traces, we have seen ACK packets being received out of order, and RST packets sent in response. We should test if we have any packets still in host queue. Signed-off-by: Eric Dumazet <[email protected]> Cc: Tom Herbert <[email protected]> Cc: Yuchung Cheng <[email protected]> Cc: Neal Cardwell <[email protected]> Signed-off-by: David S. Miller <[email protected]>
sjhung · May 24, 2013 · 547669d · 547669d
1 parent 7a1a0cb
commit 547669d
Showing 1 changed file with 6 additions and 4 deletions.
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
@@ -874,11 +874,13 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 							   &md5);
 	tcp_header_size = tcp_options_size + sizeof(struct tcphdr);
 
-	if (tcp_packets_in_flight(tp) == 0) {
+	if (tcp_packets_in_flight(tp) == 0)
 		tcp_ca_event(sk, CA_EVENT_TX_START);
-		skb->ooo_okay = 1;
-	} else
-		skb->ooo_okay = 0;
+
+	/* if no packet is in qdisc/device queue, then allow XPS to select
+	 * another queue.
+	 */
+	skb->ooo_okay = sk_wmem_alloc_get(sk) == 0;
 
 	skb_push(skb, tcp_header_size);
 	skb_reset_transport_header(skb);