2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1982, 1986, 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
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36 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
42 #include "opt_callout_profiling.h"
45 #include "opt_timer.h"
49 #include <sys/param.h>
50 #include <sys/systm.h>
52 #include <sys/callout.h>
53 #include <sys/domainset.h>
55 #include <sys/interrupt.h>
56 #include <sys/kernel.h>
59 #include <sys/malloc.h>
60 #include <sys/mutex.h>
63 #include <sys/sleepqueue.h>
64 #include <sys/sysctl.h>
69 #include <ddb/db_sym.h>
70 #include <machine/_inttypes.h>
74 #include <machine/cpu.h>
77 #ifndef NO_EVENTTIMERS
78 DPCPU_DECLARE(sbintime_t, hardclocktime);
81 SDT_PROVIDER_DEFINE(callout_execute);
82 SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *");
83 SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *");
85 #ifdef CALLOUT_PROFILING
87 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0,
88 "Average number of items examined per softclock call. Units = 1/1000");
89 static int avg_gcalls;
90 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0,
91 "Average number of Giant callouts made per softclock call. Units = 1/1000");
92 static int avg_lockcalls;
93 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0,
94 "Average number of lock callouts made per softclock call. Units = 1/1000");
95 static int avg_mpcalls;
96 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0,
97 "Average number of MP callouts made per softclock call. Units = 1/1000");
98 static int avg_depth_dir;
99 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0,
100 "Average number of direct callouts examined per callout_process call. "
102 static int avg_lockcalls_dir;
103 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD,
104 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per "
105 "callout_process call. Units = 1/1000");
106 static int avg_mpcalls_dir;
107 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir,
108 0, "Average number of MP direct callouts made per callout_process call. "
113 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0,
114 "Number of entries in callwheel and size of timeout() preallocation");
117 static int pin_default_swi = 1;
118 static int pin_pcpu_swi = 1;
120 static int pin_default_swi = 0;
121 static int pin_pcpu_swi = 0;
124 SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi,
125 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)");
126 SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi,
127 0, "Pin the per-CPU swis (except PCPU 0, which is also default");
131 * allocate more timeout table slots when table overflows.
133 static u_int __read_mostly callwheelsize;
134 static u_int __read_mostly callwheelmask;
137 * The callout cpu exec entities represent informations necessary for
138 * describing the state of callouts currently running on the CPU and the ones
139 * necessary for migrating callouts to the new callout cpu. In particular,
140 * the first entry of the array cc_exec_entity holds informations for callout
141 * running in SWI thread context, while the second one holds informations
142 * for callout running directly from hardware interrupt context.
143 * The cached informations are very important for deferring migration when
144 * the migrating callout is already running.
147 struct callout *cc_curr;
148 callout_func_t *cc_drain;
152 callout_func_t *ce_migration_func;
153 void *ce_migration_arg;
154 sbintime_t ce_migration_time;
155 sbintime_t ce_migration_prec;
156 int ce_migration_cpu;
163 * There is one struct callout_cpu per cpu, holding all relevant
164 * state for the callout processing thread on the individual CPU.
167 struct mtx_padalign cc_lock;
168 struct cc_exec cc_exec_entity[2];
169 struct callout *cc_next;
170 struct callout_list *cc_callwheel;
171 struct callout_tailq cc_expireq;
172 sbintime_t cc_firstevent;
173 sbintime_t cc_lastscan;
178 char cc_ktr_event_name[20];
182 #define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION)
184 #define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr
185 #define cc_exec_last_func(cc, dir) cc->cc_exec_entity[dir].cc_last_func
186 #define cc_exec_last_arg(cc, dir) cc->cc_exec_entity[dir].cc_last_arg
187 #define cc_exec_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain
188 #define cc_exec_next(cc) cc->cc_next
189 #define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel
190 #define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting
192 #define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func
193 #define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg
194 #define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu
195 #define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time
196 #define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec
198 struct callout_cpu cc_cpu[MAXCPU];
199 #define CPUBLOCK MAXCPU
200 #define CC_CPU(cpu) (&cc_cpu[(cpu)])
201 #define CC_SELF() CC_CPU(PCPU_GET(cpuid))
203 struct callout_cpu cc_cpu;
204 #define CC_CPU(cpu) &cc_cpu
205 #define CC_SELF() &cc_cpu
207 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock)
208 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock)
209 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED)
211 static int __read_mostly cc_default_cpu;
213 static void callout_cpu_init(struct callout_cpu *cc, int cpu);
214 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc,
215 #ifdef CALLOUT_PROFILING
216 int *mpcalls, int *lockcalls, int *gcalls,
220 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures");
224 * cc_curr - If a callout is in progress, it is cc_curr.
225 * If cc_curr is non-NULL, threads waiting in
226 * callout_drain() will be woken up as soon as the
227 * relevant callout completes.
228 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held
229 * guarantees that the current callout will not run.
230 * The softclock() function sets this to 0 before it
231 * drops callout_lock to acquire c_lock, and it calls
232 * the handler only if curr_cancelled is still 0 after
233 * cc_lock is successfully acquired.
234 * cc_waiting - If a thread is waiting in callout_drain(), then
235 * callout_wait is nonzero. Set only when
236 * cc_curr is non-NULL.
240 * Resets the execution entity tied to a specific callout cpu.
243 cc_cce_cleanup(struct callout_cpu *cc, int direct)
246 cc_exec_curr(cc, direct) = NULL;
247 cc_exec_cancel(cc, direct) = false;
248 cc_exec_waiting(cc, direct) = false;
250 cc_migration_cpu(cc, direct) = CPUBLOCK;
251 cc_migration_time(cc, direct) = 0;
252 cc_migration_prec(cc, direct) = 0;
253 cc_migration_func(cc, direct) = NULL;
254 cc_migration_arg(cc, direct) = NULL;
259 * Checks if migration is requested by a specific callout cpu.
262 cc_cce_migrating(struct callout_cpu *cc, int direct)
266 return (cc_migration_cpu(cc, direct) != CPUBLOCK);
273 * Kernel low level callwheel initialization
274 * called on the BSP during kernel startup.
277 callout_callwheel_init(void *dummy)
279 struct callout_cpu *cc;
283 * Calculate the size of the callout wheel and the preallocated
284 * timeout() structures.
285 * XXX: Clip callout to result of previous function of maxusers
286 * maximum 384. This is still huge, but acceptable.
288 ncallout = imin(16 + maxproc + maxfiles, 18508);
289 TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
292 * Calculate callout wheel size, should be next power of two higher
295 callwheelsize = 1 << fls(ncallout);
296 callwheelmask = callwheelsize - 1;
299 * Fetch whether we're pinning the swi's or not.
301 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi);
302 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi);
305 * Initialize callout wheels. The software interrupt threads
308 cc_default_cpu = PCPU_GET(cpuid);
311 callout_cpu_init(cc, cpu);
314 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL);
317 * Initialize the per-cpu callout structures.
320 callout_cpu_init(struct callout_cpu *cc, int cpu)
324 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE);
326 cc->cc_callwheel = malloc_domainset(sizeof(struct callout_list) *
327 callwheelsize, M_CALLOUT,
328 DOMAINSET_PREF(pcpu_find(cpu)->pc_domain), M_WAITOK);
329 for (i = 0; i < callwheelsize; i++)
330 LIST_INIT(&cc->cc_callwheel[i]);
331 TAILQ_INIT(&cc->cc_expireq);
332 cc->cc_firstevent = SBT_MAX;
333 for (i = 0; i < 2; i++)
334 cc_cce_cleanup(cc, i);
336 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name),
337 "callwheel cpu %d", cpu);
343 * Switches the cpu tied to a specific callout.
344 * The function expects a locked incoming callout cpu and returns with
345 * locked outcoming callout cpu.
347 static struct callout_cpu *
348 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu)
350 struct callout_cpu *new_cc;
352 MPASS(c != NULL && cc != NULL);
356 * Avoid interrupts and preemption firing after the callout cpu
357 * is blocked in order to avoid deadlocks as the new thread
358 * may be willing to acquire the callout cpu lock.
363 new_cc = CC_CPU(new_cpu);
372 * Start softclock threads.
375 start_softclock(void *dummy)
377 struct callout_cpu *cc;
378 char name[MAXCOMLEN];
381 struct intr_event *ie;
385 snprintf(name, sizeof(name), "clock (%d)", cpu);
387 if (swi_add(&ie, name, softclock, cc, SWI_CLOCK,
388 INTR_MPSAFE, &cc->cc_cookie))
389 panic("died while creating standard software ithreads");
390 if (cpu == cc_default_cpu)
391 pin_swi = pin_default_swi;
393 pin_swi = pin_pcpu_swi;
394 if (pin_swi && (intr_event_bind(ie, cpu) != 0)) {
395 printf("%s: %s clock couldn't be pinned to cpu %d\n",
397 cpu == cc_default_cpu ? "default" : "per-cpu",
402 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL);
404 #define CC_HASH_SHIFT 8
407 callout_hash(sbintime_t sbt)
410 return (sbt >> (32 - CC_HASH_SHIFT));
414 callout_get_bucket(sbintime_t sbt)
417 return (callout_hash(sbt) & callwheelmask);
421 callout_process(sbintime_t now)
423 struct callout *tmp, *tmpn;
424 struct callout_cpu *cc;
425 struct callout_list *sc;
426 sbintime_t first, last, max, tmp_max;
428 u_int firstb, lastb, nowb;
429 #ifdef CALLOUT_PROFILING
430 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0;
434 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET);
436 /* Compute the buckets of the last scan and present times. */
437 firstb = callout_hash(cc->cc_lastscan);
438 cc->cc_lastscan = now;
439 nowb = callout_hash(now);
441 /* Compute the last bucket and minimum time of the bucket after it. */
443 lookahead = (SBT_1S / 16);
444 else if (nowb - firstb == 1)
445 lookahead = (SBT_1S / 8);
447 lookahead = (SBT_1S / 2);
449 first += (lookahead / 2);
451 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT));
452 lastb = callout_hash(last) - 1;
456 * Check if we wrapped around the entire wheel from the last scan.
457 * In case, we need to scan entirely the wheel for pending callouts.
459 if (lastb - firstb >= callwheelsize) {
460 lastb = firstb + callwheelsize - 1;
461 if (nowb - firstb >= callwheelsize)
465 /* Iterate callwheel from firstb to nowb and then up to lastb. */
467 sc = &cc->cc_callwheel[firstb & callwheelmask];
468 tmp = LIST_FIRST(sc);
469 while (tmp != NULL) {
470 /* Run the callout if present time within allowed. */
471 if (tmp->c_time <= now) {
473 * Consumer told us the callout may be run
474 * directly from hardware interrupt context.
476 if (tmp->c_iflags & CALLOUT_DIRECT) {
477 #ifdef CALLOUT_PROFILING
481 LIST_NEXT(tmp, c_links.le);
482 cc->cc_bucket = firstb & callwheelmask;
483 LIST_REMOVE(tmp, c_links.le);
484 softclock_call_cc(tmp, cc,
485 #ifdef CALLOUT_PROFILING
486 &mpcalls_dir, &lockcalls_dir, NULL,
489 tmp = cc_exec_next(cc);
490 cc_exec_next(cc) = NULL;
492 tmpn = LIST_NEXT(tmp, c_links.le);
493 LIST_REMOVE(tmp, c_links.le);
494 TAILQ_INSERT_TAIL(&cc->cc_expireq,
496 tmp->c_iflags |= CALLOUT_PROCESSED;
501 /* Skip events from distant future. */
502 if (tmp->c_time >= max)
505 * Event minimal time is bigger than present maximal
506 * time, so it cannot be aggregated.
508 if (tmp->c_time > last) {
512 /* Update first and last time, respecting this event. */
513 if (tmp->c_time < first)
515 tmp_max = tmp->c_time + tmp->c_precision;
519 tmp = LIST_NEXT(tmp, c_links.le);
521 /* Proceed with the next bucket. */
524 * Stop if we looked after present time and found
525 * some event we can't execute at now.
526 * Stop if we looked far enough into the future.
528 } while (((int)(firstb - lastb)) <= 0);
529 cc->cc_firstevent = last;
530 #ifndef NO_EVENTTIMERS
531 cpu_new_callout(curcpu, last, first);
533 #ifdef CALLOUT_PROFILING
534 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8;
535 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8;
536 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8;
538 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET);
540 * swi_sched acquires the thread lock, so we don't want to call it
541 * with cc_lock held; incorrect locking order.
543 if (!TAILQ_EMPTY(&cc->cc_expireq))
544 swi_sched(cc->cc_cookie, 0);
547 static struct callout_cpu *
548 callout_lock(struct callout *c)
550 struct callout_cpu *cc;
556 if (cpu == CPUBLOCK) {
557 while (c->c_cpu == CPUBLOCK)
572 callout_cc_add(struct callout *c, struct callout_cpu *cc,
573 sbintime_t sbt, sbintime_t precision, void (*func)(void *),
574 void *arg, int cpu, int flags)
579 if (sbt < cc->cc_lastscan)
580 sbt = cc->cc_lastscan;
582 c->c_iflags |= CALLOUT_PENDING;
583 c->c_iflags &= ~CALLOUT_PROCESSED;
584 c->c_flags |= CALLOUT_ACTIVE;
585 if (flags & C_DIRECT_EXEC)
586 c->c_iflags |= CALLOUT_DIRECT;
589 c->c_precision = precision;
590 bucket = callout_get_bucket(c->c_time);
591 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x",
592 c, (int)(c->c_precision >> 32),
593 (u_int)(c->c_precision & 0xffffffff));
594 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le);
595 if (cc->cc_bucket == bucket)
596 cc_exec_next(cc) = c;
597 #ifndef NO_EVENTTIMERS
599 * Inform the eventtimers(4) subsystem there's a new callout
600 * that has been inserted, but only if really required.
602 if (SBT_MAX - c->c_time < c->c_precision)
603 c->c_precision = SBT_MAX - c->c_time;
604 sbt = c->c_time + c->c_precision;
605 if (sbt < cc->cc_firstevent) {
606 cc->cc_firstevent = sbt;
607 cpu_new_callout(cpu, sbt, c->c_time);
613 softclock_call_cc(struct callout *c, struct callout_cpu *cc,
614 #ifdef CALLOUT_PROFILING
615 int *mpcalls, int *lockcalls, int *gcalls,
619 struct rm_priotracker tracker;
620 callout_func_t *c_func, *drain;
622 struct lock_class *class;
623 struct lock_object *c_lock;
624 uintptr_t lock_status;
627 struct callout_cpu *new_cc;
628 callout_func_t *new_func;
631 sbintime_t new_prec, new_time;
633 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
634 sbintime_t sbt1, sbt2;
636 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */
637 static callout_func_t *lastfunc;
640 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING,
641 ("softclock_call_cc: pend %p %x", c, c->c_iflags));
642 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE,
643 ("softclock_call_cc: act %p %x", c, c->c_flags));
644 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL;
646 if (c->c_flags & CALLOUT_SHAREDLOCK) {
647 if (class == &lock_class_rm)
648 lock_status = (uintptr_t)&tracker;
655 c_iflags = c->c_iflags;
656 c->c_iflags &= ~CALLOUT_PENDING;
658 cc_exec_curr(cc, direct) = c;
659 cc_exec_last_func(cc, direct) = c_func;
660 cc_exec_last_arg(cc, direct) = c_arg;
661 cc_exec_cancel(cc, direct) = false;
662 cc_exec_drain(cc, direct) = NULL;
664 if (c_lock != NULL) {
665 class->lc_lock(c_lock, lock_status);
667 * The callout may have been cancelled
668 * while we switched locks.
670 if (cc_exec_cancel(cc, direct)) {
671 class->lc_unlock(c_lock);
674 /* The callout cannot be stopped now. */
675 cc_exec_cancel(cc, direct) = true;
676 if (c_lock == &Giant.lock_object) {
677 #ifdef CALLOUT_PROFILING
680 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p",
683 #ifdef CALLOUT_PROFILING
686 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p",
690 #ifdef CALLOUT_PROFILING
693 CTR3(KTR_CALLOUT, "callout %p func %p arg %p",
696 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running",
697 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct);
698 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
701 THREAD_NO_SLEEPING();
702 SDT_PROBE1(callout_execute, , , callout__start, c);
704 SDT_PROBE1(callout_execute, , , callout__end, c);
705 THREAD_SLEEPING_OK();
706 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
710 if (lastfunc != c_func || sbt2 > maxdt * 2) {
713 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n",
714 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec);
720 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle");
721 CTR1(KTR_CALLOUT, "callout %p finished", c);
722 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0)
723 class->lc_unlock(c_lock);
726 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr"));
727 cc_exec_curr(cc, direct) = NULL;
728 if (cc_exec_drain(cc, direct)) {
729 drain = cc_exec_drain(cc, direct);
730 cc_exec_drain(cc, direct) = NULL;
735 if (cc_exec_waiting(cc, direct)) {
737 * There is someone waiting for the
738 * callout to complete.
739 * If the callout was scheduled for
740 * migration just cancel it.
742 if (cc_cce_migrating(cc, direct)) {
743 cc_cce_cleanup(cc, direct);
746 * It should be assert here that the callout is not
747 * destroyed but that is not easy.
749 c->c_iflags &= ~CALLOUT_DFRMIGRATION;
751 cc_exec_waiting(cc, direct) = false;
753 wakeup(&cc_exec_waiting(cc, direct));
755 } else if (cc_cce_migrating(cc, direct)) {
758 * If the callout was scheduled for
759 * migration just perform it now.
761 new_cpu = cc_migration_cpu(cc, direct);
762 new_time = cc_migration_time(cc, direct);
763 new_prec = cc_migration_prec(cc, direct);
764 new_func = cc_migration_func(cc, direct);
765 new_arg = cc_migration_arg(cc, direct);
766 cc_cce_cleanup(cc, direct);
769 * It should be assert here that the callout is not destroyed
770 * but that is not easy.
772 * As first thing, handle deferred callout stops.
774 if (!callout_migrating(c)) {
776 "deferred cancelled %p func %p arg %p",
777 c, new_func, new_arg);
780 c->c_iflags &= ~CALLOUT_DFRMIGRATION;
782 new_cc = callout_cpu_switch(c, cc, new_cpu);
783 flags = (direct) ? C_DIRECT_EXEC : 0;
784 callout_cc_add(c, new_cc, new_time, new_prec, new_func,
785 new_arg, new_cpu, flags);
789 panic("migration should not happen");
795 * The callout mechanism is based on the work of Adam M. Costello and
796 * George Varghese, published in a technical report entitled "Redesigning
797 * the BSD Callout and Timer Facilities" and modified slightly for inclusion
798 * in FreeBSD by Justin T. Gibbs. The original work on the data structures
799 * used in this implementation was published by G. Varghese and T. Lauck in
800 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for
801 * the Efficient Implementation of a Timer Facility" in the Proceedings of
802 * the 11th ACM Annual Symposium on Operating Systems Principles,
803 * Austin, Texas Nov 1987.
807 * Software (low priority) clock interrupt.
808 * Run periodic events from timeout queue.
813 struct callout_cpu *cc;
815 #ifdef CALLOUT_PROFILING
816 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0;
819 cc = (struct callout_cpu *)arg;
821 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) {
822 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
823 softclock_call_cc(c, cc,
824 #ifdef CALLOUT_PROFILING
825 &mpcalls, &lockcalls, &gcalls,
828 #ifdef CALLOUT_PROFILING
832 #ifdef CALLOUT_PROFILING
833 avg_depth += (depth * 1000 - avg_depth) >> 8;
834 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8;
835 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8;
836 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8;
842 callout_when(sbintime_t sbt, sbintime_t precision, int flags,
843 sbintime_t *res, sbintime_t *prec_res)
845 sbintime_t to_sbt, to_pr;
847 if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) {
849 *prec_res = precision;
852 if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt)
854 if ((flags & C_HARDCLOCK) != 0 ||
855 #ifdef NO_EVENTTIMERS
856 sbt >= sbt_timethreshold) {
857 to_sbt = getsbinuptime();
859 /* Add safety belt for the case of hz > 1000. */
860 to_sbt += tc_tick_sbt - tick_sbt;
862 sbt >= sbt_tickthreshold) {
864 * Obtain the time of the last hardclock() call on
865 * this CPU directly from the kern_clocksource.c.
866 * This value is per-CPU, but it is equal for all
870 to_sbt = DPCPU_GET(hardclocktime);
873 to_sbt = DPCPU_GET(hardclocktime);
877 if (cold && to_sbt == 0)
878 to_sbt = sbinuptime();
879 if ((flags & C_HARDCLOCK) == 0)
882 to_sbt = sbinuptime();
883 if (SBT_MAX - to_sbt < sbt)
888 to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp :
889 sbt >> C_PRELGET(flags));
890 *prec_res = to_pr > precision ? to_pr : precision;
894 * New interface; clients allocate their own callout structures.
896 * callout_reset() - establish or change a timeout
897 * callout_stop() - disestablish a timeout
898 * callout_init() - initialize a callout structure so that it can
899 * safely be passed to callout_reset() and callout_stop()
901 * <sys/callout.h> defines three convenience macros:
903 * callout_active() - returns truth if callout has not been stopped,
904 * drained, or deactivated since the last time the callout was
906 * callout_pending() - returns truth if callout is still waiting for timeout
907 * callout_deactivate() - marks the callout as having been serviced
910 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec,
911 callout_func_t *ftn, void *arg, int cpu, int flags)
913 sbintime_t to_sbt, precision;
914 struct callout_cpu *cc;
915 int cancelled, direct;
921 } else if ((cpu >= MAXCPU) ||
922 ((CC_CPU(cpu))->cc_inited == 0)) {
923 /* Invalid CPU spec */
924 panic("Invalid CPU in callout %d", cpu);
926 callout_when(sbt, prec, flags, &to_sbt, &precision);
929 * This flag used to be added by callout_cc_add, but the
930 * first time you call this we could end up with the
931 * wrong direct flag if we don't do it before we add.
933 if (flags & C_DIRECT_EXEC) {
938 KASSERT(!direct || c->c_lock == NULL,
939 ("%s: direct callout %p has lock", __func__, c));
940 cc = callout_lock(c);
942 * Don't allow migration if the user does not care.
948 if (cc_exec_curr(cc, direct) == c) {
950 * We're being asked to reschedule a callout which is
951 * currently in progress. If there is a lock then we
952 * can cancel the callout if it has not really started.
954 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct))
955 cancelled = cc_exec_cancel(cc, direct) = true;
956 if (cc_exec_waiting(cc, direct) || cc_exec_drain(cc, direct)) {
958 * Someone has called callout_drain to kill this
959 * callout. Don't reschedule.
961 CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
962 cancelled ? "cancelled" : "failed to cancel",
963 c, c->c_func, c->c_arg);
968 if (callout_migrating(c)) {
970 * This only occurs when a second callout_reset_sbt_on
971 * is made after a previous one moved it into
972 * deferred migration (below). Note we do *not* change
973 * the prev_cpu even though the previous target may
976 cc_migration_cpu(cc, direct) = cpu;
977 cc_migration_time(cc, direct) = to_sbt;
978 cc_migration_prec(cc, direct) = precision;
979 cc_migration_func(cc, direct) = ftn;
980 cc_migration_arg(cc, direct) = arg;
987 if (c->c_iflags & CALLOUT_PENDING) {
988 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) {
989 if (cc_exec_next(cc) == c)
990 cc_exec_next(cc) = LIST_NEXT(c, c_links.le);
991 LIST_REMOVE(c, c_links.le);
993 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
996 c->c_iflags &= ~ CALLOUT_PENDING;
997 c->c_flags &= ~ CALLOUT_ACTIVE;
1002 * If the callout must migrate try to perform it immediately.
1003 * If the callout is currently running, just defer the migration
1004 * to a more appropriate moment.
1006 if (c->c_cpu != cpu) {
1007 if (cc_exec_curr(cc, direct) == c) {
1009 * Pending will have been removed since we are
1010 * actually executing the callout on another
1011 * CPU. That callout should be waiting on the
1012 * lock the caller holds. If we set both
1013 * active/and/pending after we return and the
1014 * lock on the executing callout proceeds, it
1015 * will then see pending is true and return.
1016 * At the return from the actual callout execution
1017 * the migration will occur in softclock_call_cc
1018 * and this new callout will be placed on the
1019 * new CPU via a call to callout_cpu_switch() which
1020 * will get the lock on the right CPU followed
1021 * by a call callout_cc_add() which will add it there.
1022 * (see above in softclock_call_cc()).
1024 cc_migration_cpu(cc, direct) = cpu;
1025 cc_migration_time(cc, direct) = to_sbt;
1026 cc_migration_prec(cc, direct) = precision;
1027 cc_migration_func(cc, direct) = ftn;
1028 cc_migration_arg(cc, direct) = arg;
1029 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING);
1030 c->c_flags |= CALLOUT_ACTIVE;
1032 "migration of %p func %p arg %p in %d.%08x to %u deferred",
1033 c, c->c_func, c->c_arg, (int)(to_sbt >> 32),
1034 (u_int)(to_sbt & 0xffffffff), cpu);
1038 cc = callout_cpu_switch(c, cc, cpu);
1042 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags);
1043 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x",
1044 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32),
1045 (u_int)(to_sbt & 0xffffffff));
1052 * Common idioms that can be optimized in the future.
1055 callout_schedule_on(struct callout *c, int to_ticks, int cpu)
1057 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu);
1061 callout_schedule(struct callout *c, int to_ticks)
1063 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu);
1067 _callout_stop_safe(struct callout *c, int flags, callout_func_t *drain)
1069 struct callout_cpu *cc, *old_cc;
1070 struct lock_class *class;
1071 int direct, sq_locked, use_lock;
1072 int cancelled, not_on_a_list;
1074 if ((flags & CS_DRAIN) != 0)
1075 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock,
1076 "calling %s", __func__);
1078 KASSERT((flags & CS_DRAIN) == 0 || drain == NULL,
1079 ("Cannot set drain callback and CS_DRAIN flag at the same time"));
1082 * Some old subsystems don't hold Giant while running a callout_stop(),
1083 * so just discard this check for the moment.
1085 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) {
1086 if (c->c_lock == &Giant.lock_object)
1087 use_lock = mtx_owned(&Giant);
1090 class = LOCK_CLASS(c->c_lock);
1091 class->lc_assert(c->c_lock, LA_XLOCKED);
1095 if (c->c_iflags & CALLOUT_DIRECT) {
1103 cc = callout_lock(c);
1105 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) ==
1106 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) &&
1107 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) {
1109 * Special case where this slipped in while we
1110 * were migrating *as* the callout is about to
1111 * execute. The caller probably holds the lock
1112 * the callout wants.
1114 * Get rid of the migration first. Then set
1115 * the flag that tells this code *not* to
1116 * try to remove it from any lists (its not
1117 * on one yet). When the callout wheel runs,
1118 * it will ignore this callout.
1120 c->c_iflags &= ~CALLOUT_PENDING;
1121 c->c_flags &= ~CALLOUT_ACTIVE;
1128 * If the callout was migrating while the callout cpu lock was
1129 * dropped, just drop the sleepqueue lock and check the states
1132 if (sq_locked != 0 && cc != old_cc) {
1135 sleepq_release(&cc_exec_waiting(old_cc, direct));
1140 panic("migration should not happen");
1145 * If the callout is running, try to stop it or drain it.
1147 if (cc_exec_curr(cc, direct) == c) {
1149 * Succeed we to stop it or not, we must clear the
1150 * active flag - this is what API users expect. If we're
1151 * draining and the callout is currently executing, first wait
1152 * until it finishes.
1154 if ((flags & CS_DRAIN) == 0)
1155 c->c_flags &= ~CALLOUT_ACTIVE;
1157 if ((flags & CS_DRAIN) != 0) {
1159 * The current callout is running (or just
1160 * about to run) and blocking is allowed, so
1161 * just wait for the current invocation to
1164 while (cc_exec_curr(cc, direct) == c) {
1166 * Use direct calls to sleepqueue interface
1167 * instead of cv/msleep in order to avoid
1168 * a LOR between cc_lock and sleepqueue
1169 * chain spinlocks. This piece of code
1170 * emulates a msleep_spin() call actually.
1172 * If we already have the sleepqueue chain
1173 * locked, then we can safely block. If we
1174 * don't already have it locked, however,
1175 * we have to drop the cc_lock to lock
1176 * it. This opens several races, so we
1177 * restart at the beginning once we have
1178 * both locks. If nothing has changed, then
1179 * we will end up back here with sq_locked
1185 &cc_exec_waiting(cc, direct));
1192 * Migration could be cancelled here, but
1193 * as long as it is still not sure when it
1194 * will be packed up, just let softclock()
1197 cc_exec_waiting(cc, direct) = true;
1201 &cc_exec_waiting(cc, direct),
1202 &cc->cc_lock.lock_object, "codrain",
1205 &cc_exec_waiting(cc, direct),
1210 /* Reacquire locks previously released. */
1214 c->c_flags &= ~CALLOUT_ACTIVE;
1215 } else if (use_lock &&
1216 !cc_exec_cancel(cc, direct) && (drain == NULL)) {
1219 * The current callout is waiting for its
1220 * lock which we hold. Cancel the callout
1221 * and return. After our caller drops the
1222 * lock, the callout will be skipped in
1223 * softclock(). This *only* works with a
1224 * callout_stop() *not* callout_drain() or
1225 * callout_async_drain().
1227 cc_exec_cancel(cc, direct) = true;
1228 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
1229 c, c->c_func, c->c_arg);
1230 KASSERT(!cc_cce_migrating(cc, direct),
1231 ("callout wrongly scheduled for migration"));
1232 if (callout_migrating(c)) {
1233 c->c_iflags &= ~CALLOUT_DFRMIGRATION;
1235 cc_migration_cpu(cc, direct) = CPUBLOCK;
1236 cc_migration_time(cc, direct) = 0;
1237 cc_migration_prec(cc, direct) = 0;
1238 cc_migration_func(cc, direct) = NULL;
1239 cc_migration_arg(cc, direct) = NULL;
1243 KASSERT(!sq_locked, ("sleepqueue chain locked"));
1245 } else if (callout_migrating(c)) {
1247 * The callout is currently being serviced
1248 * and the "next" callout is scheduled at
1249 * its completion with a migration. We remove
1250 * the migration flag so it *won't* get rescheduled,
1251 * but we can't stop the one thats running so
1254 c->c_iflags &= ~CALLOUT_DFRMIGRATION;
1257 * We can't call cc_cce_cleanup here since
1258 * if we do it will remove .ce_curr and
1259 * its still running. This will prevent a
1260 * reschedule of the callout when the
1261 * execution completes.
1263 cc_migration_cpu(cc, direct) = CPUBLOCK;
1264 cc_migration_time(cc, direct) = 0;
1265 cc_migration_prec(cc, direct) = 0;
1266 cc_migration_func(cc, direct) = NULL;
1267 cc_migration_arg(cc, direct) = NULL;
1269 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p",
1270 c, c->c_func, c->c_arg);
1272 KASSERT(cc_exec_drain(cc, direct) == NULL,
1273 ("callout drain function already set to %p",
1274 cc_exec_drain(cc, direct)));
1275 cc_exec_drain(cc, direct) = drain;
1278 return ((flags & CS_EXECUTING) != 0);
1280 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
1281 c, c->c_func, c->c_arg);
1283 KASSERT(cc_exec_drain(cc, direct) == NULL,
1284 ("callout drain function already set to %p",
1285 cc_exec_drain(cc, direct)));
1286 cc_exec_drain(cc, direct) = drain;
1289 KASSERT(!sq_locked, ("sleepqueue chain still locked"));
1290 cancelled = ((flags & CS_EXECUTING) != 0);
1295 sleepq_release(&cc_exec_waiting(cc, direct));
1297 if ((c->c_iflags & CALLOUT_PENDING) == 0) {
1298 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
1299 c, c->c_func, c->c_arg);
1301 * For not scheduled and not executing callout return
1304 if (cc_exec_curr(cc, direct) != c)
1310 c->c_iflags &= ~CALLOUT_PENDING;
1311 c->c_flags &= ~CALLOUT_ACTIVE;
1313 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
1314 c, c->c_func, c->c_arg);
1315 if (not_on_a_list == 0) {
1316 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) {
1317 if (cc_exec_next(cc) == c)
1318 cc_exec_next(cc) = LIST_NEXT(c, c_links.le);
1319 LIST_REMOVE(c, c_links.le);
1321 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
1329 callout_init(struct callout *c, int mpsafe)
1331 bzero(c, sizeof *c);
1334 c->c_iflags = CALLOUT_RETURNUNLOCKED;
1336 c->c_lock = &Giant.lock_object;
1339 c->c_cpu = cc_default_cpu;
1343 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags)
1345 bzero(c, sizeof *c);
1347 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0,
1348 ("callout_init_lock: bad flags %d", flags));
1349 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0,
1350 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock"));
1351 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags &
1352 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class",
1354 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK);
1355 c->c_cpu = cc_default_cpu;
1358 #ifdef APM_FIXUP_CALLTODO
1360 * Adjust the kernel calltodo timeout list. This routine is used after
1361 * an APM resume to recalculate the calltodo timer list values with the
1362 * number of hz's we have been sleeping. The next hardclock() will detect
1363 * that there are fired timers and run softclock() to execute them.
1365 * Please note, I have not done an exhaustive analysis of what code this
1366 * might break. I am motivated to have my select()'s and alarm()'s that
1367 * have expired during suspend firing upon resume so that the applications
1368 * which set the timer can do the maintanence the timer was for as close
1369 * as possible to the originally intended time. Testing this code for a
1370 * week showed that resuming from a suspend resulted in 22 to 25 timers
1371 * firing, which seemed independent on whether the suspend was 2 hours or
1372 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu>
1375 adjust_timeout_calltodo(struct timeval *time_change)
1378 unsigned long delta_ticks;
1381 * How many ticks were we asleep?
1382 * (stolen from tvtohz()).
1385 /* Don't do anything */
1386 if (time_change->tv_sec < 0)
1388 else if (time_change->tv_sec <= LONG_MAX / 1000000)
1389 delta_ticks = howmany(time_change->tv_sec * 1000000 +
1390 time_change->tv_usec, tick) + 1;
1391 else if (time_change->tv_sec <= LONG_MAX / hz)
1392 delta_ticks = time_change->tv_sec * hz +
1393 howmany(time_change->tv_usec, tick) + 1;
1395 delta_ticks = LONG_MAX;
1397 if (delta_ticks > INT_MAX)
1398 delta_ticks = INT_MAX;
1401 * Now rip through the timer calltodo list looking for timers
1405 /* don't collide with softclock() */
1407 for (p = calltodo.c_next; p != NULL; p = p->c_next) {
1408 p->c_time -= delta_ticks;
1410 /* Break if the timer had more time on it than delta_ticks */
1414 /* take back the ticks the timer didn't use (p->c_time <= 0) */
1415 delta_ticks = -p->c_time;
1421 #endif /* APM_FIXUP_CALLTODO */
1424 flssbt(sbintime_t sbt)
1427 sbt += (uint64_t)sbt >> 1;
1428 if (sizeof(long) >= sizeof(sbintime_t))
1431 return (flsl(((uint64_t)sbt) >> 32) + 32);
1436 * Dump immediate statistic snapshot of the scheduled callouts.
1439 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS)
1441 struct callout *tmp;
1442 struct callout_cpu *cc;
1443 struct callout_list *sc;
1444 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t;
1445 int ct[64], cpr[64], ccpbk[32];
1446 int error, val, i, count, tcum, pcum, maxc, c, medc;
1450 error = sysctl_handle_int(oidp, &val, 0, req);
1451 if (error != 0 || req->newptr == NULL)
1454 st = spr = maxt = maxpr = 0;
1455 bzero(ccpbk, sizeof(ccpbk));
1456 bzero(ct, sizeof(ct));
1457 bzero(cpr, sizeof(cpr));
1462 for (i = 0; i < callwheelsize; i++) {
1463 sc = &cc->cc_callwheel[i];
1465 LIST_FOREACH(tmp, sc, c_links.le) {
1467 t = tmp->c_time - now;
1471 spr += tmp->c_precision / SBT_1US;
1474 if (tmp->c_precision > maxpr)
1475 maxpr = tmp->c_precision;
1477 cpr[flssbt(tmp->c_precision)]++;
1481 ccpbk[fls(c + c / 2)]++;
1487 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++)
1489 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0;
1490 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++)
1492 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0;
1493 for (i = 0, c = 0; i < 32 && c < count / 2; i++)
1495 medc = (i >= 2) ? (1 << (i - 2)) : 0;
1497 printf("Scheduled callouts statistic snapshot:\n");
1498 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n",
1499 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT);
1500 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n",
1502 count / callwheelsize / mp_ncpus,
1503 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000,
1505 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n",
1506 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32,
1507 (st / count) / 1000000, (st / count) % 1000000,
1508 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32);
1509 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n",
1510 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32,
1511 (spr / count) / 1000000, (spr / count) % 1000000,
1512 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32);
1513 printf(" Distribution: \tbuckets\t time\t tcum\t"
1515 for (i = 0, tcum = pcum = 0; i < 64; i++) {
1516 if (ct[i] == 0 && cpr[i] == 0)
1518 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0;
1521 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n",
1522 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32,
1523 i - 1 - (32 - CC_HASH_SHIFT),
1524 ct[i], tcum, cpr[i], pcum);
1528 SYSCTL_PROC(_kern, OID_AUTO, callout_stat,
1529 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
1530 0, 0, sysctl_kern_callout_stat, "I",
1531 "Dump immediate statistic snapshot of the scheduled callouts");
1535 _show_callout(struct callout *c)
1538 db_printf("callout %p\n", c);
1539 #define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e);
1540 db_printf(" &c_links = %p\n", &(c->c_links));
1541 C_DB_PRINTF("%" PRId64, c_time);
1542 C_DB_PRINTF("%" PRId64, c_precision);
1543 C_DB_PRINTF("%p", c_arg);
1544 C_DB_PRINTF("%p", c_func);
1545 C_DB_PRINTF("%p", c_lock);
1546 C_DB_PRINTF("%#x", c_flags);
1547 C_DB_PRINTF("%#x", c_iflags);
1548 C_DB_PRINTF("%d", c_cpu);
1552 DB_SHOW_COMMAND(callout, db_show_callout)
1556 db_printf("usage: show callout <struct callout *>\n");
1560 _show_callout((struct callout *)addr);
1564 _show_last_callout(int cpu, int direct, const char *dirstr)
1566 struct callout_cpu *cc;
1570 func = cc_exec_last_func(cc, direct);
1571 arg = cc_exec_last_arg(cc, direct);
1572 db_printf("cpu %d last%s callout function: %p ", cpu, dirstr, func);
1573 db_printsym((db_expr_t)func, DB_STGY_ANY);
1574 db_printf("\ncpu %d last%s callout argument: %p\n", cpu, dirstr, arg);
1577 DB_SHOW_COMMAND(callout_last, db_show_callout_last)
1582 if (addr < 0 || addr > mp_maxid || CPU_ABSENT(addr)) {
1583 db_printf("no such cpu: %d\n", (int)addr);
1592 while (cpu <= last) {
1593 if (!CPU_ABSENT(cpu)) {
1594 _show_last_callout(cpu, 0, "");
1595 _show_last_callout(cpu, 1, " direct");