Let the number of timecounters follow hz, otherwise people with

HZ=BIGNUM will strain the assumptions behind timecounters to the
point where they break.

This may or may not help people seeing microuptime() backwards messages.

Make the global timecounter variable volatile, it makes no difference in
the code GCC generates, but it makes represents the intent correctly.

Thanks to:	jdp
MFC after:	2 weeks

2 files changed, 4 insertions, 3 deletions

diff --git a/sys/kern/kern_tc.c b/sys/kern/kern_tc.c
index 92e11c3..fa1832a 100644
--- a/sys/kern/kern_tc.c
+++ b/sys/kern/kern_tc.c
@@ -24,7 +24,7 @@
  * Number of timecounters used to implement stable storage
  */
 #ifndef NTIMECOUNTER
-#define NTIMECOUNTER	45
+#define NTIMECOUNTER	hz
 #endif
 
 static MALLOC_DEFINE(M_TIMECOUNTER, "timecounter", 
@@ -80,7 +80,7 @@ static struct timecounter dummy_timecounter = {
 	"dummy"
 };
 
-struct timecounter *timecounter = &dummy_timecounter;
+struct timecounter *volatile timecounter = &dummy_timecounter;
 
 static __inline unsigned
 tco_delta(struct timecounter *tc)
@@ -263,6 +263,7 @@ tc_init(struct timecounter *tc)
 	tc->tc_other = t1;
 	*t1 = *tc;
 	t2 = t1;
+	t3 = NULL;
 	for (i = 1; i < NTIMECOUNTER; i++) {
 		MALLOC(t3, struct timecounter *, sizeof *t3,
 		    M_TIMECOUNTER, M_WAITOK);
diff --git a/sys/sys/timetc.h b/sys/sys/timetc.h
index ac62dc7..9897f4d 100644
--- a/sys/sys/timetc.h
+++ b/sys/sys/timetc.h
@@ -93,7 +93,7 @@ struct timecounter {
 };
 
 #ifdef _KERNEL
-extern struct timecounter *timecounter;
+extern struct timecounter *volatile timecounter;
 
 void	tc_init __P((struct timecounter *tc));
 void	tc_setclock __P((struct timespec *ts));