tcp_lp: cache tcp_time_stamp

tcp_time_stamp will become slightly more expensive soon,
cache its value.

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

diff --git a/net/ipv4/tcp_lp.c b/net/ipv4/tcp_lp.c
index d6fb6c067af4641f232b94e7c590c212648e8173..ef3122abb3734a63011fba035f7a7aae431da8de 100644 (file)
--- a/net/ipv4/tcp_lp.c
+++ b/net/ipv4/tcp_lp.c
@@ -264,18 +264,19 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        struct lp *lp = inet_csk_ca(sk);
+       u32 now = tcp_time_stamp;
        u32 delta;
 
        if (sample->rtt_us > 0)
                tcp_lp_rtt_sample(sk, sample->rtt_us);
 
        /* calc inference */
-       delta = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
+       delta = now - tp->rx_opt.rcv_tsecr;
        if ((s32)delta > 0)
                lp->inference = 3 * delta;
 
        /* test if within inference */
-       if (lp->last_drop && (tcp_time_stamp - lp->last_drop < lp->inference))
+       if (lp->last_drop && (now - lp->last_drop < lp->inference))
                lp->flag |= LP_WITHIN_INF;
        else
                lp->flag &= ~LP_WITHIN_INF;
@@ -312,7 +313,7 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample)
                tp->snd_cwnd = max(tp->snd_cwnd >> 1U, 1U);
 
        /* record this drop time */
-       lp->last_drop = tcp_time_stamp;
+       lp->last_drop = now;
 }
 
 static struct tcp_congestion_ops tcp_lp __read_mostly = {