From 2b13af8ade38ef3afe48d60c518c64010cfa8b0d Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 25 Oct 2021 09:48:18 -0700
Subject: [PATCH] net: avoid dirtying sk->sk_napi_id
sk_napi_id is located in a cache line that can be kept read mostly.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
include/net/busy_poll.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h
index 40296ed976a97..4202c609bb0b0 100644
--- a/include/net/busy_poll.h
+++ b/include/net/busy_poll.h
@@ -130,7 +130,8 @@ static inline void skb_mark_napi_id(struct sk_buff *skb,
static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
- WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
+ if (unlikely(READ_ONCE(sk->sk_napi_id) != skb->napi_id))
+ WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
#endif
sk_rx_queue_set(sk, skb);
}
--
2.30.2