tcp: switch tcp_internal_pacing() to tcp_wstamp_ns

Now TCP keeps track of tcp_wstamp_ns, recording the earliest
departure time of next packet, we can remove duplicate code
from tcp_internal_pacing()

This removes one ktime_get_tai_ns() call, and a divide.

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

1 files changed, 4 insertions, 13 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 2adb719e97b8..fe7855b090e4 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -993,21 +993,12 @@ enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer)
         return HRTIMER_NORESTART;
 }
 
-static void tcp_internal_pacing(struct sock *sk, const struct sk_buff *skb)
+static void tcp_internal_pacing(struct sock *sk)
 {
-        u64 len_ns;
-        u32 rate;
-
         if (!tcp_needs_internal_pacing(sk))
                 return;
-        rate = sk->sk_pacing_rate;
-        if (!rate || rate == ~0U)
-                return;
-
-        len_ns = (u64)skb->len * NSEC_PER_SEC;
-        do_div(len_ns, rate);
         hrtimer_start(&tcp_sk(sk)->pacing_timer,
-                      ktime_add_ns(ktime_get_tai_ns(), len_ns),
+                      ns_to_ktime(tcp_sk(sk)->tcp_wstamp_ns),
                       HRTIMER_MODE_ABS_PINNED_SOFT);
         sock_hold(sk);
 }
@@ -1026,7 +1017,8 @@ static void tcp_update_skb_after_send(struct sock *sk, struct sk_buff *skb)
                  */
                 if (rate != ~0U && rate && tp->data_segs_out >= 10) {
                         tp->tcp_wstamp_ns += div_u64((u64)skb->len * NSEC_PER_SEC, rate);
-                        /* TODO: update internal pacing here */
+
+                        tcp_internal_pacing(sk);
                 }
         }
         list_move_tail(&skb->tcp_tsorted_anchor, &tp->tsorted_sent_queue);
@@ -1167,7 +1159,6 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb,
                 tcp_event_data_sent(tp, sk);
                 tp->data_segs_out += tcp_skb_pcount(skb);
                 tp->bytes_sent += skb->len - tcp_header_size;
-                tcp_internal_pacing(sk, skb);
         }
 
         if (after(tcb->end_seq, tp->snd_nxt) || tcb->seq == tcb->end_seq)