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Message-Id: <20180921155154.49489-6-edumazet@google.com>
Date: Fri, 21 Sep 2018 08:51:50 -0700
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>
Cc: netdev <netdev@...r.kernel.org>, Van Jacobson <vanj@...gle.com>,
Neal Cardwell <ncardwell@...gle.com>,
Yuchung Cheng <ycheng@...gle.com>,
Soheil Hassas Yeganeh <soheil@...gle.com>,
Willem de Bruijn <willemb@...gle.com>,
Eric Dumazet <edumazet@...gle.com>,
Eric Dumazet <eric.dumazet@...il.com>
Subject: [PATCH net-next 5/9] tcp: provide earliest departure time in skb->tstamp
Switch internal TCP skb->skb_mstamp to skb->skb_mstamp_ns,
from usec units to nsec units.
Do not clear skb->tstamp before entering IP stacks in TX,
so that qdisc or devices can implement pacing based on the
earliest departure time instead of socket sk->sk_pacing_rate
Packets are fed with tcp_wstamp_ns, and following patch
will update tcp_wstamp_ns when both TCP and sch_fq switch to
the earliest departure time mechanism.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
include/linux/skbuff.h | 2 +-
include/net/tcp.h | 6 +++---
net/ipv4/syncookies.c | 2 +-
net/ipv4/tcp.c | 2 +-
net/ipv4/tcp_output.c | 13 ++++++-------
net/ipv4/tcp_timer.c | 2 +-
6 files changed, 13 insertions(+), 14 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index e3a53ca4a9b51b84b7d75ce87485d4d9109a4cf2..86f337e9a81d5eff360335a19ab09f26ae48fca8 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -689,7 +689,7 @@ struct sk_buff {
union {
ktime_t tstamp;
- u64 skb_mstamp;
+ u64 skb_mstamp_ns; /* earliest departure time */
};
/*
* This is the control buffer. It is free to use for every
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 370198fdc65d3e863104665e20faefd0e5a09b92..ff15d8e0d525715b17671e64f6abdead9df0a8f3 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -761,13 +761,13 @@ static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0)
static inline u32 tcp_skb_timestamp(const struct sk_buff *skb)
{
- return div_u64(skb->skb_mstamp, USEC_PER_SEC / TCP_TS_HZ);
+ return div_u64(skb->skb_mstamp_ns, NSEC_PER_SEC / TCP_TS_HZ);
}
/* provide the departure time in us unit */
static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb)
{
- return skb->skb_mstamp;
+ return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC);
}
@@ -813,7 +813,7 @@ struct tcp_skb_cb {
#define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
#define TCPCB_LOST 0x04 /* SKB is lost */
#define TCPCB_TAGBITS 0x07 /* All tag bits */
-#define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp) */
+#define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */
#define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \
TCPCB_REPAIRED)
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index c3387dfd725bf99bcddefb9fb4f1dc98f5dd7f23..606f868d9f3fde1c3140aa7eecde87d2ec32b5f2 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -88,7 +88,7 @@ u64 cookie_init_timestamp(struct request_sock *req)
ts <<= TSBITS;
ts |= options;
}
- return (u64)ts * (USEC_PER_SEC / TCP_TS_HZ);
+ return (u64)ts * (NSEC_PER_SEC / TCP_TS_HZ);
}
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 67670fac7c8de510df351fe3a835b554cc4759a9..69c236943f56bd0749e5efb18de97e69898f1bde 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1295,7 +1295,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
copy = size_goal;
/* All packets are restored as if they have
- * already been sent. skb_mstamp isn't set to
+ * already been sent. skb_mstamp_ns isn't set to
* avoid wrong rtt estimation.
*/
if (tp->repair)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 5a8105e84f7c1a876bbd15e8050c2574c1fbe162..957f7a0e21c06cae9f0d3bed57017bbc0a36c880 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1014,7 +1014,7 @@ static void tcp_internal_pacing(struct sock *sk, const struct sk_buff *skb)
static void tcp_update_skb_after_send(struct tcp_sock *tp, struct sk_buff *skb)
{
- skb->skb_mstamp = tp->tcp_mstamp;
+ skb->skb_mstamp_ns = tp->tcp_wstamp_ns;
list_move_tail(&skb->tcp_tsorted_anchor, &tp->tsorted_sent_queue);
}
@@ -1061,7 +1061,7 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb,
if (unlikely(!skb))
return -ENOBUFS;
}
- skb->skb_mstamp = tp->tcp_mstamp;
+ skb->skb_mstamp_ns = tp->tcp_wstamp_ns;
inet = inet_sk(sk);
tcb = TCP_SKB_CB(skb);
@@ -1165,8 +1165,7 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb,
skb_shinfo(skb)->gso_segs = tcp_skb_pcount(skb);
skb_shinfo(skb)->gso_size = tcp_skb_mss(skb);
- /* Our usage of tstamp should remain private */
- skb->tstamp = 0;
+ /* Leave earliest departure time in skb->tstamp (skb->skb_mstamp_ns) */
/* Cleanup our debris for IP stacks */
memset(skb->cb, 0, max(sizeof(struct inet_skb_parm),
@@ -3221,10 +3220,10 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
memset(&opts, 0, sizeof(opts));
#ifdef CONFIG_SYN_COOKIES
if (unlikely(req->cookie_ts))
- skb->skb_mstamp = cookie_init_timestamp(req);
+ skb->skb_mstamp_ns = cookie_init_timestamp(req);
else
#endif
- skb->skb_mstamp = tcp_clock_us();
+ skb->skb_mstamp_ns = tcp_clock_ns();
#ifdef CONFIG_TCP_MD5SIG
rcu_read_lock();
@@ -3440,7 +3439,7 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
err = tcp_transmit_skb(sk, syn_data, 1, sk->sk_allocation);
- syn->skb_mstamp = syn_data->skb_mstamp;
+ syn->skb_mstamp_ns = syn_data->skb_mstamp_ns;
/* Now full SYN+DATA was cloned and sent (or not),
* remove the SYN from the original skb (syn_data)
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 7fdf222a0bdfe9775970082f6b5dcdcc82b2ae1a..61023d50cd604d5e19464a32c33b65d29c75c81e 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -360,7 +360,7 @@ static void tcp_probe_timer(struct sock *sk)
*/
start_ts = tcp_skb_timestamp(skb);
if (!start_ts)
- skb->skb_mstamp = tp->tcp_mstamp;
+ skb->skb_mstamp_ns = tp->tcp_wstamp_ns;
else if (icsk->icsk_user_timeout &&
(s32)(tcp_time_stamp(tp) - start_ts) > icsk->icsk_user_timeout)
goto abort;
--
2.19.0.444.g18242da7ef-goog
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