svn commit: r309148 - head/sys/kern

[John Baldwin]

Author: jhb
Date: Fri Nov 25 18:02:43 2016
New Revision: 309148
URL: https://svnweb.freebsd.org/changeset/base/309148

Log:
  Permit timed sleeps for threads other than thread0 before timers are working.
  
  The callout subsystem already handles early callouts and schedules
  the first clock interrupt appropriately based on the currently pending
  callouts.  The one nit to fix was that callouts scheduled via C_HARDCLOCK
  during early boot could fire too early once timers were enabled as the
  per-CPU base time is always zero until timers are initialized.  The change
  in callout_when() handles this case by using the current uptime as the
  base time of the callout during bootup if the per-CPU base time is zero.
  
  Reviewed by:	kib
  MFC after:	2 weeks
  Sponsored by:	Netflix

Modified:
  head/sys/kern/kern_timeout.c
  head/sys/kern/subr_sleepqueue.c

Modified: head/sys/kern/kern_timeout.c
==============================================================================
--- head/sys/kern/kern_timeout.c	Fri Nov 25 18:01:32 2016	(r309147)
+++ head/sys/kern/kern_timeout.c	Fri Nov 25 18:02:43 2016	(r309148)
@@ -981,6 +981,8 @@ callout_when(sbintime_t sbt, sbintime_t 
 		spinlock_exit();
 #endif
 #endif
+		if (cold && to_sbt == 0)
+			to_sbt = sbinuptime();
 		if ((flags & C_HARDCLOCK) == 0)
 			to_sbt += tick_sbt;
 	} else

Modified: head/sys/kern/subr_sleepqueue.c
==============================================================================
--- head/sys/kern/subr_sleepqueue.c	Fri Nov 25 18:01:32 2016	(r309147)
+++ head/sys/kern/subr_sleepqueue.c	Fri Nov 25 18:02:43 2016	(r309148)
@@ -386,7 +386,7 @@ sleepq_set_timeout_sbt(void *wchan, sbin
 	MPASS(TD_ON_SLEEPQ(td));
 	MPASS(td->td_sleepqueue == NULL);
 	MPASS(wchan != NULL);
-	if (cold)
+	if (cold && td == &thread0)
 		panic("timed sleep before timers are working");
 	KASSERT(td->td_sleeptimo == 0, ("td %d %p td_sleeptimo %jx",
 	    td->td_tid, td, (uintmax_t)td->td_sleeptimo));