From: Eric Dumazet <edumazet@google.com>
Date: Tue, 27 Nov 2018 22:42:00 +0000 (-0800)
Subject: tcp: hint compiler about sack flows
X-Git-Tag: for-linus-20190104~82^2~178^2~3
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=ebeef4bcccf4681ba3de04fbf3a005f6054f7999;p=linux-2.6-block.git

tcp: hint compiler about sack flows

Tell the compiler that most TCP flows are using SACK these days.

There is no need to add the unlikely() clause in tcp_is_reno(),
the compiler is able to infer it.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 63e37dd1c274..0c61bf0a06da 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1124,7 +1124,7 @@ void tcp_rate_check_app_limited(struct sock *sk);
  */
 static inline int tcp_is_sack(const struct tcp_sock *tp)
 {
-	return tp->rx_opt.sack_ok;
+	return likely(tp->rx_opt.sack_ok);
 }
 
 static inline bool tcp_is_reno(const struct tcp_sock *tp)