From: Eric Dumazet <edumazet@google.com>
Date: Mon, 15 Oct 2018 16:37:58 +0000 (-0700)
Subject: tcp: cdg: use tcp high resolution clock cache
X-Git-Tag: v4.20-rc1~14^2~62^2
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=825e1c523d5000f067a1614e4a66bb282a2d373c;p=uclinux-h8%2Flinux.git

tcp: cdg: use tcp high resolution clock cache

We store in tcp socket a cache of most recent high resolution
clock, there is no need to call local_clock() again, since
this cache is good enough.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp_cdg.c b/net/ipv4/tcp_cdg.c
index 06fbe102a425..37eebd910396 100644
--- a/net/ipv4/tcp_cdg.c
+++ b/net/ipv4/tcp_cdg.c
@@ -146,7 +146,7 @@ static void tcp_cdg_hystart_update(struct sock *sk)
 		return;
 
 	if (hystart_detect & HYSTART_ACK_TRAIN) {
-		u32 now_us = div_u64(local_clock(), NSEC_PER_USEC);
+		u32 now_us = tp->tcp_mstamp;
 
 		if (ca->last_ack == 0 || !tcp_is_cwnd_limited(sk)) {
 			ca->last_ack = now_us;