[RFC PATCH v2 1/5] tcp: Added a function to retrieve pacing timer
From: Natale Patriciello <hidden>
Date: 2017-10-14 11:49:49
Subsystem:
networking [general], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
Allow congestion control modules to set a custom pacing time between the transmission of segments. Moreover, it is assumed that the time returned by the congestion module in the past is firm, until the timer expires; therefore, do not re-start the timer if it is already active. Signed-off-by: Natale Patriciello <redacted> --- include/net/tcp.h | 2 ++ net/ipv4/tcp_output.c | 36 +++++++++++++++++++++++++----------- 2 files changed, 27 insertions(+), 11 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 89974c5286d8..42c7aa96c4cf 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h@@ -1015,6 +1015,8 @@ struct tcp_congestion_ops { /* get info for inet_diag (optional) */ size_t (*get_info)(struct sock *sk, u32 ext, int *attr, union tcp_cc_info *info); + /* get the expiration time for the pacing timer (optional) */ + u64 (*get_pacing_time)(struct sock *sk); char name[TCP_CA_NAME_MAX]; struct module *owner;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 0bc9e46a5369..ec5977156c26 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c@@ -950,22 +950,36 @@ static bool tcp_needs_internal_pacing(const struct sock *sk) return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED; } +static bool tcp_pacing_timer_check(const struct sock *sk) +{ + return hrtimer_active(&tcp_sk(sk)->pacing_timer); +} + static void tcp_internal_pacing(struct sock *sk, const struct sk_buff *skb) { + const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; u64 len_ns; - u32 rate; if (!tcp_needs_internal_pacing(sk)) return; - rate = sk->sk_pacing_rate; - 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); + + if (ca_ops && ca_ops->get_pacing_time) { + if (tcp_pacing_timer_check(sk)) + return; + + len_ns = ca_ops->get_pacing_time(sk); + } else { + u32 rate = sk->sk_pacing_rate; + + 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, ktime_add_ns(ktime_get(), len_ns), HRTIMER_MODE_ABS_PINNED);
@@ -2123,7 +2137,7 @@ static int tcp_mtu_probe(struct sock *sk) static bool tcp_pacing_check(const struct sock *sk) { return tcp_needs_internal_pacing(sk) && - hrtimer_active(&tcp_sk(sk)->pacing_timer); + tcp_pacing_timer_check(sk); } /* TCP Small Queues :
--
2.14.2