[TCP]: Don't set SKB owner in tcp_transmit_skb().
The data itself is already charged to the SKB, doing
the skb_set_owner_w() just generates a lot of noise and
extra atomics we don't really need.
Lmbench improvements on lat_tcp are minimal:
before:
TCP latency using localhost: 23.2701 microseconds
TCP latency using localhost: 23.1994 microseconds
TCP latency using localhost: 23.2257 microseconds
after:
TCP latency using localhost: 22.8380 microseconds
TCP latency using localhost: 22.9465 microseconds
TCP latency using localhost: 22.8462 microseconds
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 23633bf..def32d8 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -288,9 +288,8 @@
!(IPCB(skb)->flags & IPSKB_REROUTED));
}
-int ip_queue_xmit(struct sk_buff *skb, int ipfragok)
+int ip_queue_xmit(struct sk_buff *skb, struct sock *sk, int ipfragok)
{
- struct sock *sk = skb->sk;
struct inet_sock *inet = inet_sk(sk);
struct ip_options *opt = inet->opt;
struct rtable *rt;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index ca40615..f63e99a 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -426,7 +426,6 @@
th = (struct tcphdr *) skb_push(skb, tcp_header_size);
skb->h.th = th;
- skb_set_owner_w(skb, sk);
/* Build TCP header and checksum it. */
th->source = inet->sport;
@@ -479,7 +478,7 @@
if (after(tcb->end_seq, tp->snd_nxt) || tcb->seq == tcb->end_seq)
TCP_INC_STATS(TCP_MIB_OUTSEGS);
- err = icsk->icsk_af_ops->queue_xmit(skb, 0);
+ err = icsk->icsk_af_ops->queue_xmit(skb, sk, 0);
if (likely(err <= 0))
return err;