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authorEric Dumazet <edumazet@google.com>2018-06-20 16:07:35 -0400
committerDavid S. Miller <davem@davemloft.net>2018-06-22 13:59:22 +0900
commitcadefe5f584abaac40dce72009e4de738cbff467 (patch)
tree1b40f040d84e576d231826bd19593918eb597d86
parent3f484a6e766740c9cb89cf576fdceeec49e221fd (diff)
tcp_bbr: fix bbr pacing rate for internal pacing
This commit makes BBR use only the MSS (without any headers) to calculate pacing rates when internal TCP-layer pacing is used. This is necessary to achieve the correct pacing behavior in this case, since tcp_internal_pacing() uses only the payload length to calculate pacing delays. Signed-off-by: Kevin Yang <yyd@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/tcp.h11
-rw-r--r--net/ipv4/tcp_bbr.c6
-rw-r--r--net/ipv4/tcp_output.c14
3 files changed, 16 insertions, 15 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 0448e7c5d2b4..822ee49ed0f9 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1184,6 +1184,17 @@ static inline bool tcp_is_cwnd_limited(const struct sock *sk)
return tp->is_cwnd_limited;
}
+/* BBR congestion control needs pacing.
+ * Same remark for SO_MAX_PACING_RATE.
+ * sch_fq packet scheduler is efficiently handling pacing,
+ * but is not always installed/used.
+ * Return true if TCP stack should pace packets itself.
+ */
+static inline bool tcp_needs_internal_pacing(const struct sock *sk)
+{
+ return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED;
+}
+
/* Something is really bad, we could not queue an additional packet,
* because qdisc is full or receiver sent a 0 window.
* We do not want to add fuel to the fire, or abort too early,
diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c
index 58e2f479ffb4..3b5f45b9e81e 100644
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -205,7 +205,11 @@ static u32 bbr_bw(const struct sock *sk)
*/
static u64 bbr_rate_bytes_per_sec(struct sock *sk, u64 rate, int gain)
{
- rate *= tcp_mss_to_mtu(sk, tcp_sk(sk)->mss_cache);
+ unsigned int mss = tcp_sk(sk)->mss_cache;
+
+ if (!tcp_needs_internal_pacing(sk))
+ mss = tcp_mss_to_mtu(sk, mss);
+ rate *= mss;
rate *= gain;
rate >>= BBR_SCALE;
rate *= USEC_PER_SEC;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 8e08b409c71e..f8f6129160dd 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -973,17 +973,6 @@ enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer)
return HRTIMER_NORESTART;
}
-/* BBR congestion control needs pacing.
- * Same remark for SO_MAX_PACING_RATE.
- * sch_fq packet scheduler is efficiently handling pacing,
- * but is not always installed/used.
- * Return true if TCP stack should pace packets itself.
- */
-static bool tcp_needs_internal_pacing(const struct sock *sk)
-{
- return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED;
-}
-
static void tcp_internal_pacing(struct sock *sk, const struct sk_buff *skb)
{
u64 len_ns;
@@ -995,9 +984,6 @@ static void tcp_internal_pacing(struct sock *sk, const struct sk_buff *skb)
if (!rate || rate == ~0U)
return;
- /* Should account for header sizes as sch_fq does,
- * but lets make things simple.
- */
len_ns = (u64)skb->len * NSEC_PER_SEC;
do_div(len_ns, rate);
hrtimer_start(&tcp_sk(sk)->pacing_timer,