netdev - [PATCH net-next 10/10] udp: use skb_attempt_defer

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Message-ID: <20250916160951.541279-11-edumazet@google.com>
Date: Tue, 16 Sep 2025 16:09:51 +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>, Willem de Bruijn <willemb@...gle.com>, 
	Kuniyuki Iwashima <kuniyu@...gle.com>, David Ahern <dsahern@...nel.org>, netdev@...r.kernel.org, 
	eric.dumazet@...il.com, Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next 10/10] udp: use skb_attempt_defer_free()

Move skb freeing from udp recvmsg() path to the cpu
which allocated/received it, as TCP did in linux-5.17.

This increases max thoughput by 20% to 30%, depending
on number of BH producers.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/ipv4/udp.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 7d1444821ee51a19cd5fd0dd5b8d096104c9283c..0c40426628eb2306b609881341a51307c4993871 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1825,6 +1825,13 @@ void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len)
 	if (unlikely(READ_ONCE(udp_sk(sk)->peeking_with_offset)))
 		sk_peek_offset_bwd(sk, len);
 
+	if (!skb_shared(skb)) {
+		if (unlikely(udp_skb_has_head_state(skb)))
+			skb_release_head_state(skb);
+		skb_attempt_defer_free(skb);
+		return;
+	}
+
 	if (!skb_unref(skb))
 		return;
 
-- 
2.51.0.384.g4c02a37b29-goog