[PATCH v1 net-next 1/5] net: add add indirect call wrapper in skb_release_head_state()

[Eric Dumazet <edumazet@google.com>]

While stress testing UDP senders on a host with expensive indirect
calls, I found cpus processing TX completions where showing
a very high cost (20%) in sock_wfree() due to
CONFIG_MITIGATION_RETPOLINE=y.

Take care of TCP and UDP TX destructors and use INDIRECT_CALL_3() macro.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/core/skbuff.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index bc12790017b0b5c0be99f8fb9d362b3730fa4eb0..692e3a70e75ed14786a67d72bc2ebc0282eee2be 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1136,7 +1136,16 @@ void skb_release_head_state(struct sk_buff *skb)
 	skb_dst_drop(skb);
 	if (skb->destructor) {
 		DEBUG_NET_WARN_ON_ONCE(in_hardirq());
-		skb->destructor(skb);
+#ifdef CONFIG_INET
+		INDIRECT_CALL_3(skb->destructor,
+				tcp_wfree, __sock_wfree, sock_wfree,
+				skb);
+#else
+		INDIRECT_CALL_1(skb->destructor,
+				sock_wfree,
+				skb);
+
+#endif
 	}
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 	nf_conntrack_put(skb_nfct(skb));
-- 
2.51.0.740.g6adb054d12-goog