netdev - [PATCH RFC net-next 1/5] net: add add indirect call wrapper in skb_release_head

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Message-ID: <20251006193103.2684156-2-edumazet@google.com>
Date: Mon,  6 Oct 2025 19:30:59 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>
Cc: Simon Horman <horms@...nel.org>, Jamal Hadi Salim <jhs@...atatu.com>, 
	Cong Wang <xiyou.wangcong@...il.com>, Jiri Pirko <jiri@...nulli.us>, 
	Kuniyuki Iwashima <kuniyu@...gle.com>, Willem de Bruijn <willemb@...gle.com>, netdev@...r.kernel.org, 
	eric.dumazet@...il.com, Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH RFC net-next 1/5] net: add add indirect call wrapper in skb_release_head_state()

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@...gle.com>
---
 net/core/skbuff.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index bc12790017b0b5c0be99f8fb9d362b3730fa4eb0..c9c06f9a8d6085f8d0907b412e050a60c835a6e8 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1136,7 +1136,9 @@ 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);
+		INDIRECT_CALL_3(skb->destructor,
+				tcp_wfree, __sock_wfree, sock_wfree,
+				skb);
 	}
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 	nf_conntrack_put(skb_nfct(skb));
-- 
2.51.0.618.g983fd99d29-goog