On Sat, 2017-10-14 at 13:47 +0200, Natale Patriciello wrote:
> Inform the congestion control that the pacing timer, previously set,
> has expired. The commit does not consider situations in which another
> kind of timer has expired (e.g., a tail loss probe, a retransmission
> timer...)
>
> Signed-off-by: Natale Patriciello <natale.patricie...@gmail.com>
> ---
> include/net/tcp.h | 2 ++
> net/ipv4/tcp_output.c | 6 ++++++
> 2 files changed, 8 insertions(+)
>
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index 42c7aa96c4cf..e817f0669d0e 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -1017,6 +1017,8 @@ struct tcp_congestion_ops {
> union tcp_cc_info *info);
> /* get the expiration time for the pacing timer (optional) */
> u64 (*get_pacing_time)(struct sock *sk);
> + /* the pacing timer is expired (optional) */
> + void (*pacing_timer_expired)(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 ec5977156c26..25b4cf0802f2 100644
> --- a/net/ipv4/tcp_output.c
> +++ b/net/ipv4/tcp_output.c
> @@ -2241,6 +2241,7 @@ void tcp_chrono_stop(struct sock *sk, const enum
> tcp_chrono type)
> static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int
> nonagle,
> int push_one, gfp_t gfp)
> {
> + const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops;
> struct tcp_sock *tp = tcp_sk(sk);
> struct sk_buff *skb;
> unsigned int tso_segs, sent_pkts;
> @@ -2263,6 +2264,11 @@ static bool tcp_write_xmit(struct sock *sk, unsigned
> int mss_now, int nonagle,
>
> max_segs = tcp_tso_segs(sk, mss_now);
> tcp_mstamp_refresh(tp);
> +
> + if (!tcp_pacing_timer_check(sk) &&
> + ca_ops && ca_ops->pacing_timer_expired)
> + ca_ops->pacing_timer_expired(sk);
> +
>
1) We do not want hrtimer_active() being called for each
tcp_write_xmit() ... :/
2) ca_ops can not be NULL.
->
if (ca_ops->pacing_timer_expired && !tcp_pacing_timer_check(sk))
ca_ops->pacing_timer_expired(sk);
