diff mbox

tcp: xps: fix reordering issues

Message ID 1369331060.3301.396.camel@edumazet-glaptop
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Eric Dumazet May 23, 2013, 5:44 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

commit 3853b5841c01a ("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 <edumazet@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
---
 net/ipv4/tcp_output.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)



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Comments

David Miller May 24, 2013, 1:29 a.m. UTC | #1 
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 23 May 2013 10:44:20 -0700

> From: Eric Dumazet <edumazet@google.com>
> 
> commit 3853b5841c01a ("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 <edumazet@google.com>

Applied, thanks Eric.
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diff mbox

Patch

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 536d409..ec335fa 100644
--- 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);