From fb420d5d91c1274d5966917725e71f27ed092a85 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 28 Sep 2018 10:28:44 -0700 Subject: [PATCH] tcp/fq: move back to CLOCK_MONOTONIC In the recent TCP/EDT patch series, I switched TCP and sch_fq clocks from MONOTONIC to TAI, in order to meet the choice done earlier for sch_etf packet scheduler. But sure enough, this broke some setups were the TAI clock jumps forward (by almost 50 year...), as reported by Leonard Crestez. If we want to converge later, we'll probably need to add an skb field to differentiate the clock bases, or a socket option. In the meantime, an UDP application will need to use CLOCK_MONOTONIC base for its SCM_TXTIME timestamps if using fq packet scheduler. Fixes: 72b0094f9182 ("tcp: switch tcp_clock_ns() to CLOCK_TAI base") Fixes: 142537e41923 ("net_sched: sch_fq: switch to CLOCK_TAI") Fixes: fd2bca2aa789 ("tcp: switch internal pacing timer to CLOCK_TAI") Signed-off-by: Eric Dumazet Reported-by: Leonard Crestez Tested-by: Leonard Crestez Signed-off-by: David S. Miller --- include/net/tcp.h | 2 +- net/ipv4/tcp_timer.c | 2 +- net/sched/sch_fq.c | 6 +++--- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index ff15d8e0d525..0d2929223c70 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -732,7 +732,7 @@ void tcp_send_window_probe(struct sock *sk); static inline u64 tcp_clock_ns(void) { - return ktime_get_tai_ns(); + return ktime_get_ns(); } static inline u64 tcp_clock_us(void) diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 4f661e178da8..61023d50cd60 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -758,7 +758,7 @@ void tcp_init_xmit_timers(struct sock *sk) { inet_csk_init_xmit_timers(sk, &tcp_write_timer, &tcp_delack_timer, &tcp_keepalive_timer); - hrtimer_init(&tcp_sk(sk)->pacing_timer, CLOCK_TAI, + hrtimer_init(&tcp_sk(sk)->pacing_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_SOFT); tcp_sk(sk)->pacing_timer.function = tcp_pace_kick; diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c index 628a2cdcfc6f..338222a6c664 100644 --- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -412,7 +412,7 @@ static void fq_check_throttled(struct fq_sched_data *q, u64 now) static struct sk_buff *fq_dequeue(struct Qdisc *sch) { struct fq_sched_data *q = qdisc_priv(sch); - u64 now = ktime_get_tai_ns(); + u64 now = ktime_get_ns(); struct fq_flow_head *head; struct sk_buff *skb; struct fq_flow *f; @@ -776,7 +776,7 @@ static int fq_init(struct Qdisc *sch, struct nlattr *opt, q->fq_trees_log = ilog2(1024); q->orphan_mask = 1024 - 1; q->low_rate_threshold = 550000 / 8; - qdisc_watchdog_init_clockid(&q->watchdog, sch, CLOCK_TAI); + qdisc_watchdog_init_clockid(&q->watchdog, sch, CLOCK_MONOTONIC); if (opt) err = fq_change(sch, opt, extack); @@ -831,7 +831,7 @@ static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d) st.flows_plimit = q->stat_flows_plimit; st.pkts_too_long = q->stat_pkts_too_long; st.allocation_errors = q->stat_allocation_errors; - st.time_next_delayed_flow = q->time_next_delayed_flow - ktime_get_tai_ns(); + st.time_next_delayed_flow = q->time_next_delayed_flow - ktime_get_ns(); st.flows = q->flows; st.inactive_flows = q->inactive_flows; st.throttled_flows = q->throttled_flows; -- 2.39.5