kernel: expand fixed clock interrupt periods to 64-bit values

Technically, all the current fixed clock interrupt periods fit within
an unsigned 32-bit value.  But 32-bit multiplication is an accident
waiting to happen.  So, expand the fixed periods for hardclock,
statclock, profclock, and roundrobin to 64-bit values.

One exception: statclock_mask remains 32-bit because random(9) yields
32-bit values.  Update the initclocks() comment to make it clear that
this is not an accident.

diff --git a/sys/kern/kern_clock.c b/sys/kern/kern_clock.c
index 22c62f1..d11ac4f 100644 (file)
--- a/sys/kern/kern_clock.c
+++ b/sys/kern/kern_clock.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_clock.c,v 1.119 2023/09/14 22:27:09 cheloha Exp $        */
+/*     $OpenBSD: kern_clock.c,v 1.120 2023/10/11 15:42:44 cheloha Exp $        */
 /*     $NetBSD: kern_clock.c,v 1.34 1996/06/09 04:51:03 briggs Exp $   */
 
 /*-
@@ -87,9 +87,9 @@ int   ticks = INT_MAX - (15 * 60 * HZ);
 /* Don't force early wrap around, triggers bug in inteldrm */
 volatile unsigned long jiffies;
 
-uint32_t hardclock_period;     /* [I] hardclock period (ns) */
-uint32_t statclock_avg;                /* [I] average statclock period (ns) */
-uint32_t statclock_min;                /* [I] minimum statclock period (ns) */
+uint64_t hardclock_period;     /* [I] hardclock period (ns) */
+uint64_t statclock_avg;                /* [I] average statclock period (ns) */
+uint64_t statclock_min;                /* [I] minimum statclock period (ns) */
 uint32_t statclock_mask;       /* [I] set of allowed offsets */
 int statclock_is_randomized;   /* [I] fixed or pseudorandom period? */
 
@@ -99,7 +99,8 @@ int statclock_is_randomized;  /* [I] fixed or pseudorandom period? */
 void
 initclocks(void)
 {
-       uint32_t half_avg, var;
+       uint64_t half_avg;
+       uint32_t var;
 
        /*
         * Let the machine-specific code do its bit.
@@ -114,7 +115,7 @@ initclocks(void)
 
        /*
         * Compute the average statclock() period.  Then find var, the
-        * largest power of two such that var <= statclock_avg / 2.
+        * largest 32-bit power of two such that var <= statclock_avg / 2.
         */
        statclock_avg = 1000000000 / stathz;
        half_avg = statclock_avg / 2;

diff --git a/sys/kern/sched_bsd.c b/sys/kern/sched_bsd.c
index 9298984..8f1db1e 100644 (file)
--- a/sys/kern/sched_bsd.c
+++ b/sys/kern/sched_bsd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: sched_bsd.c,v 1.87 2023/09/17 13:02:24 cheloha Exp $  */
+/*     $OpenBSD: sched_bsd.c,v 1.88 2023/10/11 15:42:44 cheloha Exp $  */
 /*     $NetBSD: kern_synch.c,v 1.37 1996/04/22 01:38:37 christos Exp $ */
 
 /*-
@@ -54,7 +54,7 @@
 #include <sys/ktrace.h>
 #endif
 
-uint32_t roundrobin_period;    /* [I] roundrobin period (ns) */
+uint64_t roundrobin_period;    /* [I] roundrobin period (ns) */
 int    lbolt;                  /* once a second sleep address */
 
 #ifdef MULTIPROCESSOR

diff --git a/sys/kern/subr_prof.c b/sys/kern/subr_prof.c
index b630890..52292b3 100644 (file)
--- a/sys/kern/subr_prof.c
+++ b/sys/kern/subr_prof.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: subr_prof.c,v 1.38 2023/09/10 03:08:05 cheloha Exp $  */
+/*     $OpenBSD: subr_prof.c,v 1.39 2023/10/11 15:42:44 cheloha Exp $  */
 /*     $NetBSD: subr_prof.c,v 1.12 1996/04/22 01:38:50 christos Exp $  */
 
 /*-
@@ -44,7 +44,7 @@
 #include <sys/syscallargs.h>
 #include <sys/user.h>
 
-uint32_t profclock_period;
+uint64_t profclock_period;
 
 #if defined(GPROF) || defined(DDBPROF)
 #include <sys/malloc.h>

diff --git a/sys/sys/resourcevar.h b/sys/sys/resourcevar.h
index fcbd990..b8dff12 100644 (file)
--- a/sys/sys/resourcevar.h
+++ b/sys/sys/resourcevar.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: resourcevar.h,v 1.29 2023/09/10 03:08:05 cheloha Exp $        */
+/*     $OpenBSD: resourcevar.h,v 1.30 2023/10/11 15:42:44 cheloha Exp $        */
 /*     $NetBSD: resourcevar.h,v 1.12 1995/11/22 23:01:53 cgd Exp $     */
 
 /*
@@ -62,7 +62,7 @@ do {                                                                  \
 
 struct clockintr;
 
-extern uint32_t profclock_period;
+extern uint64_t profclock_period;
 
 void    addupc_intr(struct proc *, u_long, u_long);
 void    addupc_task(struct proc *, u_long, u_int);

diff --git a/sys/sys/sched.h b/sys/sys/sched.h
index a54a8f7..6f4cbb6 100644 (file)
--- a/sys/sys/sched.h
+++ b/sys/sys/sched.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: sched.h,v 1.64 2023/09/14 22:07:11 cheloha Exp $      */
+/*     $OpenBSD: sched.h,v 1.65 2023/10/11 15:42:44 cheloha Exp $      */
 /* $NetBSD: sched.h,v 1.2 1999/02/28 18:14:58 ross Exp $ */
 
 /*-
@@ -146,7 +146,7 @@ struct cpustats {
 #define NICE_WEIGHT 2                  /* priorities per nice level */
 #define        ESTCPULIM(e) min((e), NICE_WEIGHT * PRIO_MAX - SCHED_PPQ)
 
-extern uint32_t roundrobin_period;
+extern uint64_t roundrobin_period;
 
 struct proc;
 void schedclock(struct proc *);

diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index 868cd68..42a1c9f 100644 (file)
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: systm.h,v 1.167 2023/09/14 20:58:51 cheloha Exp $     */
+/*     $OpenBSD: systm.h,v 1.168 2023/10/11 15:42:44 cheloha Exp $     */
 /*     $NetBSD: systm.h,v 1.50 1996/06/09 04:55:09 briggs Exp $        */
 
 /*-
@@ -233,8 +233,8 @@ int tvtohz(const struct timeval *);
 int    tstohz(const struct timespec *);
 void   realitexpire(void *);
 
-extern uint32_t hardclock_period;
-extern uint32_t statclock_avg;
+extern uint64_t hardclock_period;
+extern uint64_t statclock_avg;
 extern int statclock_is_randomized;
 
 struct clockframe;