tcp_close() schedules the reaper timeout to run immediately.
Does it need to run *immediately*? Can it wait for one tick?
I'm trying to eliminate these zero-tick timeouts because they
rely on undocumented behavior and impede an optimization I want
to make in the timeout layer.
This is the one I'm hitting most often so I'll start here.
Index: tcp_subr.c
===================================================================
RCS file: /cvs/src/sys/netinet/tcp_subr.c,v
retrieving revision 1.174
diff -u -p -r1.174 tcp_subr.c
--- tcp_subr.c 4 Oct 2018 17:33:41 -0000 1.174
+++ tcp_subr.c 24 Jul 2020 18:19:00 -0000
@@ -518,7 +518,7 @@ tcp_close(struct tcpcb *tp)
m_free(tp->t_template);
/* Free tcpcb after all pending timers have been run. */
- TCP_TIMER_ARM(tp, TCPT_REAPER, 0);
+ TCP_TIMER_ARM(tp, TCPT_REAPER, 1);
inp->inp_ppcb = NULL;
soisdisconnected(so);
