Author: rrs
Date: Thu Oct 24 05:54:30 2019
New Revision: 354013
URL: https://svnweb.freebsd.org/changeset/base/354013
Log:
Fix a small bug in bbr when running under a VM. Basically what
happens is we are more delayed in the pacer calling in so
we remove the stack from the pacer and recalculate how
much time is left after all data has been acknowledged. However
the comparision was backwards so we end up with a negative
value in the last_pacing_delay time which causes us to
add in a huge value to the next pacing time thus stalling
the connection.
Reported by: vm2.fina...@gmail.com
Modified:
head/sys/netinet/tcp_stacks/bbr.c
Modified: head/sys/netinet/tcp_stacks/bbr.c
==============================================================================
--- head/sys/netinet/tcp_stacks/bbr.c Thu Oct 24 04:12:38 2019
(r354012)
+++ head/sys/netinet/tcp_stacks/bbr.c Thu Oct 24 05:54:30 2019
(r354013)
@@ -11814,12 +11814,13 @@ bbr_do_segment_nounlock(struct mbuf *m, struct tcphdr
uint32_t del;
del = lcts -
bbr->rc_pacer_started;
- if (del >
bbr->r_ctl.rc_last_delay_val) {
+ if
(bbr->r_ctl.rc_last_delay_val > del) {
BBR_STAT_INC(bbr_force_timer_start);
bbr->r_ctl.rc_last_delay_val -= del;
bbr->rc_pacer_started =
lcts;
} else {
/* We are late */
+
bbr->r_ctl.rc_last_delay_val = 0;
BBR_STAT_INC(bbr_force_output);
(void)tp->t_fb->tfb_tcp_output(tp);
}
@@ -12278,8 +12279,9 @@ bbr_output_wtime(struct tcpcb *tp, const struct timeva
* We are early setup to adjust
* our slot time.
*/
+ uint64_t merged_val;
+
bbr->r_ctl.rc_agg_early +=
(bbr->r_ctl.rc_last_delay_val - delay_calc);
- bbr->r_ctl.rc_last_delay_val = 0;
bbr->r_agg_early_set = 1;
if (bbr->r_ctl.rc_hptsi_agg_delay) {
if (bbr->r_ctl.rc_hptsi_agg_delay >=
bbr->r_ctl.rc_agg_early) {
@@ -12292,9 +12294,13 @@ bbr_output_wtime(struct tcpcb *tp, const struct timeva
bbr->r_ctl.rc_hptsi_agg_delay = 0;
}
}
+ merged_val = bbr->rc_pacer_started;
+ merged_val <<= 32;
+ merged_val |= bbr->r_ctl.rc_last_delay_val;
bbr_log_pacing_delay_calc(bbr, inp->inp_hpts_calls,
- bbr->r_ctl.rc_agg_early, cts,
3, 0,
+ bbr->r_ctl.rc_agg_early, cts,
delay_calc, merged_val,
bbr->r_agg_early_set, 3);
+ bbr->r_ctl.rc_last_delay_val = 0;
BBR_STAT_INC(bbr_early);
delay_calc = 0;
}
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