net: rfs: enable RFS before first data packet is received

Le jeudi 16 juin 2011 à 23:38 -0400, David Miller a écrit :
> From: Ben Hutchings <bhutchings@solarflare.com>
> Date: Fri, 17 Jun 2011 00:50:46 +0100
>
> > On Wed, 2011-06-15 at 04:15 +0200, Eric Dumazet wrote:
> >> @@ -1594,6 +1594,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
> >>  			goto discard;
> >>
> >>  		if (nsk != sk) {
> >> +			sock_rps_save_rxhash(nsk, skb->rxhash);
> >>  			if (tcp_child_process(sk, nsk, skb)) {
> >>  				rsk = nsk;
> >>  				goto reset;
> >>
> >
> > I haven't tried this, but it looks reasonable to me.
> >
> > What about IPv6?  The logic in tcp_v6_do_rcv() looks very similar.
>
> Indeed ipv6 side needs the same fix.
>
> Eric please add that part and resubmit.  And in fact I might stick
> this into net-2.6 instead of net-next-2.6
>

OK, here is the net-2.6 based one then, thanks !

[PATCH v2] net: rfs: enable RFS before first data packet is received

First packet received on a passive tcp flow is not correctly RFS
steered.

One sock_rps_record_flow() call is missing in inet_accept()

But before that, we also must record rxhash when child socket is setup.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Tom Herbert <therbert@google.com>
CC: Ben Hutchings <bhutchings@solarflare.com>
CC: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@conan.davemloft.net>

net/ipv4/af_inet.c

@@ -676,6 +676,7 @@ int inet_accept(struct socket *sock, struct socket *newsock, int flags)
 
 	lock_sock(sk2);
 
+	sock_rps_record_flow(sk2);
 	WARN_ON(!((1 << sk2->sk_state) &
 		  (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_CLOSE)));
 

net/ipv4/tcp_ipv4.c

@@ -1589,6 +1589,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
 			goto discard;
 
 		if (nsk != sk) {
+			sock_rps_save_rxhash(nsk, skb->rxhash);
 			if (tcp_child_process(sk, nsk, skb)) {
 				rsk = nsk;
 				goto reset;

net/ipv6/tcp_ipv6.c

@@ -1644,6 +1644,7 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 		 * the new socket..
 		 */
 		if(nsk != sk) {
+			sock_rps_save_rxhash(nsk, skb->rxhash);
 			if (tcp_child_process(sk, nsk, skb))
 				goto reset;
 			if (opt_skb)