From 342159ee394d103db4bea1b01f932c50e66be163 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 25 Oct 2021 09:48:19 -0700
Subject: [PATCH] net: avoid dirtying sk->sk_rx_queue_mapping
sk_rx_queue_mapping is located in a cache line that should 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/sock.h | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index 99c4194cb61a..b4d3744b188a 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1916,10 +1916,8 @@ static inline void sk_rx_queue_set(struct sock *sk, const struct sk_buff *skb)
if (skb_rx_queue_recorded(skb)) {
u16 rx_queue = skb_get_rx_queue(skb);
- if (WARN_ON_ONCE(rx_queue == NO_QUEUE_MAPPING))
- return;
-
- sk->sk_rx_queue_mapping = rx_queue;
+ if (unlikely(READ_ONCE(sk->sk_rx_queue_mapping) != rx_queue))
+ WRITE_ONCE(sk->sk_rx_queue_mapping, rx_queue);
}
#endif
}