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34 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
40 #include "opt_kdtrace.h"
42 #include <sys/param.h>
43 #include <sys/systm.h>
45 #include <sys/callout.h>
46 #include <sys/condvar.h>
47 #include <sys/interrupt.h>
48 #include <sys/kernel.h>
51 #include <sys/malloc.h>
52 #include <sys/mutex.h>
55 #include <sys/sleepqueue.h>
56 #include <sys/sysctl.h>
60 #include <machine/cpu.h>
63 SDT_PROVIDER_DEFINE(callout_execute);
64 SDT_PROBE_DEFINE(callout_execute, kernel, , callout_start, callout-start);
65 SDT_PROBE_ARGTYPE(callout_execute, kernel, , callout_start, 0,
67 SDT_PROBE_DEFINE(callout_execute, kernel, , callout_end, callout-end);
68 SDT_PROBE_ARGTYPE(callout_execute, kernel, , callout_end, 0,
72 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0,
73 "Average number of items examined per softclock call. Units = 1/1000");
74 static int avg_gcalls;
75 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0,
76 "Average number of Giant callouts made per softclock call. Units = 1/1000");
77 static int avg_lockcalls;
78 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0,
79 "Average number of lock callouts made per softclock call. Units = 1/1000");
80 static int avg_mpcalls;
81 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0,
82 "Average number of MP callouts made per softclock call. Units = 1/1000");
85 * allocate more timeout table slots when table overflows.
87 int callwheelsize, callwheelbits, callwheelmask;
90 * The callout cpu migration entity represents informations necessary for
91 * describing the migrating callout to the new callout cpu.
92 * The cached informations are very important for deferring migration when
93 * the migrating callout is already running.
97 void (*ce_migration_func)(void *);
98 void *ce_migration_arg;
100 int ce_migration_ticks;
105 * There is one struct callout_cpu per cpu, holding all relevant
106 * state for the callout processing thread on the individual CPU.
108 * cc_ticks is incremented once per tick in callout_cpu().
109 * It tracks the global 'ticks' but in a way that the individual
110 * threads should not worry about races in the order in which
111 * hardclock() and hardclock_cpu() run on the various CPUs.
112 * cc_softclock is advanced in callout_cpu() to point to the
113 * first entry in cc_callwheel that may need handling. In turn,
114 * a softclock() is scheduled so it can serve the various entries i
115 * such that cc_softclock <= i <= cc_ticks .
116 * XXX maybe cc_softclock and cc_ticks should be volatile ?
118 * cc_ticks is also used in callout_reset_cpu() to determine
119 * when the callout should be served.
122 struct cc_mig_ent cc_migrating_entity;
124 struct callout *cc_callout;
125 struct callout_tailq *cc_callwheel;
126 struct callout_list cc_callfree;
127 struct callout *cc_next;
128 struct callout *cc_curr;
137 #define cc_migration_func cc_migrating_entity.ce_migration_func
138 #define cc_migration_arg cc_migrating_entity.ce_migration_arg
139 #define cc_migration_cpu cc_migrating_entity.ce_migration_cpu
140 #define cc_migration_ticks cc_migrating_entity.ce_migration_ticks
142 struct callout_cpu cc_cpu[MAXCPU];
143 #define CPUBLOCK MAXCPU
144 #define CC_CPU(cpu) (&cc_cpu[(cpu)])
145 #define CC_SELF() CC_CPU(PCPU_GET(cpuid))
147 struct callout_cpu cc_cpu;
148 #define CC_CPU(cpu) &cc_cpu
149 #define CC_SELF() &cc_cpu
151 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock)
152 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock)
153 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED)
155 static int timeout_cpu;
157 MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures");
161 * cc_curr - If a callout is in progress, it is curr_callout.
162 * If curr_callout is non-NULL, threads waiting in
163 * callout_drain() will be woken up as soon as the
164 * relevant callout completes.
165 * cc_cancel - Changing to 1 with both callout_lock and c_lock held
166 * guarantees that the current callout will not run.
167 * The softclock() function sets this to 0 before it
168 * drops callout_lock to acquire c_lock, and it calls
169 * the handler only if curr_cancelled is still 0 after
170 * c_lock is successfully acquired.
171 * cc_waiting - If a thread is waiting in callout_drain(), then
172 * callout_wait is nonzero. Set only when
173 * curr_callout is non-NULL.
177 * Resets the migration entity tied to a specific callout cpu.
180 cc_cme_cleanup(struct callout_cpu *cc)
184 cc->cc_migration_cpu = CPUBLOCK;
185 cc->cc_migration_ticks = 0;
186 cc->cc_migration_func = NULL;
187 cc->cc_migration_arg = NULL;
192 * Checks if migration is requested by a specific callout cpu.
195 cc_cme_migrating(struct callout_cpu *cc)
199 return (cc->cc_migration_cpu != CPUBLOCK);
206 * kern_timeout_callwheel_alloc() - kernel low level callwheel initialization
208 * This code is called very early in the kernel initialization sequence,
209 * and may be called more then once.
212 kern_timeout_callwheel_alloc(caddr_t v)
214 struct callout_cpu *cc;
216 timeout_cpu = PCPU_GET(cpuid);
217 cc = CC_CPU(timeout_cpu);
219 * Calculate callout wheel size
221 for (callwheelsize = 1, callwheelbits = 0;
222 callwheelsize < ncallout;
223 callwheelsize <<= 1, ++callwheelbits)
225 callwheelmask = callwheelsize - 1;
227 cc->cc_callout = (struct callout *)v;
228 v = (caddr_t)(cc->cc_callout + ncallout);
229 cc->cc_callwheel = (struct callout_tailq *)v;
230 v = (caddr_t)(cc->cc_callwheel + callwheelsize);
235 callout_cpu_init(struct callout_cpu *cc)
240 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE);
241 SLIST_INIT(&cc->cc_callfree);
242 for (i = 0; i < callwheelsize; i++) {
243 TAILQ_INIT(&cc->cc_callwheel[i]);
246 if (cc->cc_callout == NULL)
248 for (i = 0; i < ncallout; i++) {
249 c = &cc->cc_callout[i];
251 c->c_flags = CALLOUT_LOCAL_ALLOC;
252 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle);
258 * Switches the cpu tied to a specific callout.
259 * The function expects a locked incoming callout cpu and returns with
260 * locked outcoming callout cpu.
262 static struct callout_cpu *
263 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu)
265 struct callout_cpu *new_cc;
267 MPASS(c != NULL && cc != NULL);
271 * Avoid interrupts and preemption firing after the callout cpu
272 * is blocked in order to avoid deadlocks as the new thread
273 * may be willing to acquire the callout cpu lock.
278 new_cc = CC_CPU(new_cpu);
287 * kern_timeout_callwheel_init() - initialize previously reserved callwheel
290 * This code is called just once, after the space reserved for the
291 * callout wheel has been finalized.
294 kern_timeout_callwheel_init(void)
296 callout_cpu_init(CC_CPU(timeout_cpu));
300 * Start standard softclock thread.
305 start_softclock(void *dummy)
307 struct callout_cpu *cc;
312 cc = CC_CPU(timeout_cpu);
313 if (swi_add(&clk_intr_event, "clock", softclock, cc, SWI_CLOCK,
314 INTR_MPSAFE, &softclock_ih))
315 panic("died while creating standard software ithreads");
316 cc->cc_cookie = softclock_ih;
319 if (cpu == timeout_cpu)
322 if (swi_add(NULL, "clock", softclock, cc, SWI_CLOCK,
323 INTR_MPSAFE, &cc->cc_cookie))
324 panic("died while creating standard software ithreads");
325 cc->cc_callout = NULL; /* Only cpu0 handles timeout(). */
326 cc->cc_callwheel = malloc(
327 sizeof(struct callout_tailq) * callwheelsize, M_CALLOUT,
329 callout_cpu_init(cc);
334 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL);
339 struct callout_cpu *cc;
344 * Process callouts at a very low cpu priority, so we don't keep the
345 * relatively high clock interrupt priority any longer than necessary.
349 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET);
351 for (; (cc->cc_softticks - cc->cc_ticks) <= 0; cc->cc_softticks++) {
352 bucket = cc->cc_softticks & callwheelmask;
353 if (!TAILQ_EMPTY(&cc->cc_callwheel[bucket])) {
358 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET);
360 * swi_sched acquires the thread lock, so we don't want to call it
361 * with cc_lock held; incorrect locking order.
364 swi_sched(cc->cc_cookie, 0);
367 static struct callout_cpu *
368 callout_lock(struct callout *c)
370 struct callout_cpu *cc;
376 if (cpu == CPUBLOCK) {
377 while (c->c_cpu == CPUBLOCK)
392 callout_cc_add(struct callout *c, struct callout_cpu *cc, int to_ticks,
393 void (*func)(void *), void *arg, int cpu)
401 c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING);
403 c->c_time = cc->cc_ticks + to_ticks;
404 TAILQ_INSERT_TAIL(&cc->cc_callwheel[c->c_time & callwheelmask],
409 * The callout mechanism is based on the work of Adam M. Costello and
410 * George Varghese, published in a technical report entitled "Redesigning
411 * the BSD Callout and Timer Facilities" and modified slightly for inclusion
412 * in FreeBSD by Justin T. Gibbs. The original work on the data structures
413 * used in this implementation was published by G. Varghese and T. Lauck in
414 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for
415 * the Efficient Implementation of a Timer Facility" in the Proceedings of
416 * the 11th ACM Annual Symposium on Operating Systems Principles,
417 * Austin, Texas Nov 1987.
421 * Software (low priority) clock interrupt.
422 * Run periodic events from timeout queue.
427 struct callout_cpu *cc;
429 struct callout_tailq *bucket;
431 int steps; /* #steps since we last allowed interrupts */
437 struct bintime bt1, bt2;
439 static uint64_t maxdt = 36893488147419102LL; /* 2 msec */
440 static timeout_t *lastfunc;
443 #ifndef MAX_SOFTCLOCK_STEPS
444 #define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */
445 #endif /* MAX_SOFTCLOCK_STEPS */
452 cc = (struct callout_cpu *)arg;
454 while (cc->cc_softticks - 1 != cc->cc_ticks) {
456 * cc_softticks may be modified by hard clock, so cache
457 * it while we work on a given bucket.
459 curticks = cc->cc_softticks;
461 bucket = &cc->cc_callwheel[curticks & callwheelmask];
462 c = TAILQ_FIRST(bucket);
465 if (c->c_time != curticks) {
466 c = TAILQ_NEXT(c, c_links.tqe);
468 if (steps >= MAX_SOFTCLOCK_STEPS) {
470 /* Give interrupts a chance. */
478 void (*c_func)(void *);
480 struct lock_class *class;
481 struct lock_object *c_lock;
482 int c_flags, sharedlock;
484 cc->cc_next = TAILQ_NEXT(c, c_links.tqe);
485 TAILQ_REMOVE(bucket, c, c_links.tqe);
486 class = (c->c_lock != NULL) ?
487 LOCK_CLASS(c->c_lock) : NULL;
488 sharedlock = (c->c_flags & CALLOUT_SHAREDLOCK) ?
493 c_flags = c->c_flags;
494 if (c->c_flags & CALLOUT_LOCAL_ALLOC) {
495 c->c_flags = CALLOUT_LOCAL_ALLOC;
498 (c->c_flags & ~CALLOUT_PENDING);
503 if (c_lock != NULL) {
504 class->lc_lock(c_lock, sharedlock);
506 * The callout may have been cancelled
507 * while we switched locks.
510 class->lc_unlock(c_lock);
513 /* The callout cannot be stopped now. */
516 if (c_lock == &Giant.lock_object) {
519 "callout %p func %p arg %p",
523 CTR3(KTR_CALLOUT, "callout lock"
524 " %p func %p arg %p",
530 "callout mpsafe %p func %p arg %p",
536 THREAD_NO_SLEEPING();
537 SDT_PROBE(callout_execute, kernel, ,
538 callout_start, c, 0, 0, 0, 0);
540 SDT_PROBE(callout_execute, kernel, ,
541 callout_end, c, 0, 0, 0, 0);
542 THREAD_SLEEPING_OK();
545 bintime_sub(&bt2, &bt1);
546 if (bt2.frac > maxdt) {
547 if (lastfunc != c_func ||
548 bt2.frac > maxdt * 2) {
549 bintime2timespec(&bt2, &ts2);
551 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n",
553 (intmax_t)ts2.tv_sec,
560 CTR1(KTR_CALLOUT, "callout %p finished", c);
561 if ((c_flags & CALLOUT_RETURNUNLOCKED) == 0)
562 class->lc_unlock(c_lock);
566 * If the current callout is locally
567 * allocated (from timeout(9))
568 * then put it on the freelist.
570 * Note: we need to check the cached
571 * copy of c_flags because if it was not
572 * local, then it's not safe to deref the
575 if (c_flags & CALLOUT_LOCAL_ALLOC) {
576 KASSERT(c->c_flags ==
578 ("corrupted callout"));
580 SLIST_INSERT_HEAD(&cc->cc_callfree, c,
584 if (cc->cc_waiting) {
587 * There is someone waiting for the
588 * callout to complete.
589 * If the callout was scheduled for
590 * migration just cancel it.
592 if (cc_cme_migrating(cc))
596 wakeup(&cc->cc_waiting);
598 } else if (cc_cme_migrating(cc)) {
600 struct callout_cpu *new_cc;
601 void (*new_func)(void *);
603 int new_cpu, new_ticks;
606 * If the callout was scheduled for
607 * migration just perform it now.
609 new_cpu = cc->cc_migration_cpu;
610 new_ticks = cc->cc_migration_ticks;
611 new_func = cc->cc_migration_func;
612 new_arg = cc->cc_migration_arg;
616 * It should be assert here that the
617 * callout is not destroyed but that
620 new_cc = callout_cpu_switch(c, cc,
622 callout_cc_add(c, new_cc, new_ticks,
623 new_func, new_arg, new_cpu);
627 panic("migration should not happen");
635 avg_depth += (depth * 1000 - avg_depth) >> 8;
636 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8;
637 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8;
638 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8;
645 * Execute a function after a specified length of time.
648 * Cancel previous timeout function call.
650 * callout_handle_init --
651 * Initialize a handle so that using it with untimeout is benign.
653 * See AT&T BCI Driver Reference Manual for specification. This
654 * implementation differs from that one in that although an
655 * identification value is returned from timeout, the original
656 * arguments to timeout as well as the identifier are used to
657 * identify entries for untimeout.
659 struct callout_handle
660 timeout(ftn, arg, to_ticks)
665 struct callout_cpu *cc;
667 struct callout_handle handle;
669 cc = CC_CPU(timeout_cpu);
671 /* Fill in the next free callout structure. */
672 new = SLIST_FIRST(&cc->cc_callfree);
674 /* XXX Attempt to malloc first */
675 panic("timeout table full");
676 SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle);
677 callout_reset(new, to_ticks, ftn, arg);
678 handle.callout = new;
685 untimeout(ftn, arg, handle)
688 struct callout_handle handle;
690 struct callout_cpu *cc;
693 * Check for a handle that was initialized
694 * by callout_handle_init, but never used
695 * for a real timeout.
697 if (handle.callout == NULL)
700 cc = callout_lock(handle.callout);
701 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg)
702 callout_stop(handle.callout);
707 callout_handle_init(struct callout_handle *handle)
709 handle->callout = NULL;
713 * New interface; clients allocate their own callout structures.
715 * callout_reset() - establish or change a timeout
716 * callout_stop() - disestablish a timeout
717 * callout_init() - initialize a callout structure so that it can
718 * safely be passed to callout_reset() and callout_stop()
720 * <sys/callout.h> defines three convenience macros:
722 * callout_active() - returns truth if callout has not been stopped,
723 * drained, or deactivated since the last time the callout was
725 * callout_pending() - returns truth if callout is still waiting for timeout
726 * callout_deactivate() - marks the callout as having been serviced
729 callout_reset_on(struct callout *c, int to_ticks, void (*ftn)(void *),
732 struct callout_cpu *cc;
736 * Don't allow migration of pre-allocated callouts lest they
739 if (c->c_flags & CALLOUT_LOCAL_ALLOC)
741 cc = callout_lock(c);
742 if (cc->cc_curr == c) {
744 * We're being asked to reschedule a callout which is
745 * currently in progress. If there is a lock then we
746 * can cancel the callout if it has not really started.
748 if (c->c_lock != NULL && !cc->cc_cancel)
749 cancelled = cc->cc_cancel = 1;
750 if (cc->cc_waiting) {
752 * Someone has called callout_drain to kill this
753 * callout. Don't reschedule.
755 CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
756 cancelled ? "cancelled" : "failed to cancel",
757 c, c->c_func, c->c_arg);
762 if (c->c_flags & CALLOUT_PENDING) {
763 if (cc->cc_next == c) {
764 cc->cc_next = TAILQ_NEXT(c, c_links.tqe);
766 TAILQ_REMOVE(&cc->cc_callwheel[c->c_time & callwheelmask], c,
770 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING);
775 * If the callout must migrate try to perform it immediately.
776 * If the callout is currently running, just defer the migration
777 * to a more appropriate moment.
779 if (c->c_cpu != cpu) {
780 if (cc->cc_curr == c) {
781 cc->cc_migration_cpu = cpu;
782 cc->cc_migration_ticks = to_ticks;
783 cc->cc_migration_func = ftn;
784 cc->cc_migration_arg = arg;
786 "migration of %p func %p arg %p in %d to %u deferred",
787 c, c->c_func, c->c_arg, to_ticks, cpu);
791 cc = callout_cpu_switch(c, cc, cpu);
795 callout_cc_add(c, cc, to_ticks, ftn, arg, cpu);
796 CTR5(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d",
797 cancelled ? "re" : "", c, c->c_func, c->c_arg, to_ticks);
804 * Common idioms that can be optimized in the future.
807 callout_schedule_on(struct callout *c, int to_ticks, int cpu)
809 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu);
813 callout_schedule(struct callout *c, int to_ticks)
815 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu);
819 _callout_stop_safe(c, safe)
823 struct callout_cpu *cc, *old_cc;
824 struct lock_class *class;
825 int use_lock, sq_locked;
828 * Some old subsystems don't hold Giant while running a callout_stop(),
829 * so just discard this check for the moment.
831 if (!safe && c->c_lock != NULL) {
832 if (c->c_lock == &Giant.lock_object)
833 use_lock = mtx_owned(&Giant);
836 class = LOCK_CLASS(c->c_lock);
837 class->lc_assert(c->c_lock, LA_XLOCKED);
845 cc = callout_lock(c);
848 * If the callout was migrating while the callout cpu lock was
849 * dropped, just drop the sleepqueue lock and check the states
852 if (sq_locked != 0 && cc != old_cc) {
855 sleepq_release(&old_cc->cc_waiting);
860 panic("migration should not happen");
865 * If the callout isn't pending, it's not on the queue, so
866 * don't attempt to remove it from the queue. We can try to
867 * stop it by other means however.
869 if (!(c->c_flags & CALLOUT_PENDING)) {
870 c->c_flags &= ~CALLOUT_ACTIVE;
873 * If it wasn't on the queue and it isn't the current
874 * callout, then we can't stop it, so just bail.
876 if (cc->cc_curr != c) {
877 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
878 c, c->c_func, c->c_arg);
881 sleepq_release(&cc->cc_waiting);
887 * The current callout is running (or just
888 * about to run) and blocking is allowed, so
889 * just wait for the current invocation to
892 while (cc->cc_curr == c) {
895 * Use direct calls to sleepqueue interface
896 * instead of cv/msleep in order to avoid
897 * a LOR between cc_lock and sleepqueue
898 * chain spinlocks. This piece of code
899 * emulates a msleep_spin() call actually.
901 * If we already have the sleepqueue chain
902 * locked, then we can safely block. If we
903 * don't already have it locked, however,
904 * we have to drop the cc_lock to lock
905 * it. This opens several races, so we
906 * restart at the beginning once we have
907 * both locks. If nothing has changed, then
908 * we will end up back here with sq_locked
913 sleepq_lock(&cc->cc_waiting);
920 * Migration could be cancelled here, but
921 * as long as it is still not sure when it
922 * will be packed up, just let softclock()
928 sleepq_add(&cc->cc_waiting,
929 &cc->cc_lock.lock_object, "codrain",
931 sleepq_wait(&cc->cc_waiting, 0);
935 /* Reacquire locks previously released. */
939 } else if (use_lock && !cc->cc_cancel) {
941 * The current callout is waiting for its
942 * lock which we hold. Cancel the callout
943 * and return. After our caller drops the
944 * lock, the callout will be skipped in
948 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
949 c, c->c_func, c->c_arg);
950 KASSERT(!cc_cme_migrating(cc),
951 ("callout wrongly scheduled for migration"));
953 KASSERT(!sq_locked, ("sleepqueue chain locked"));
956 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
957 c, c->c_func, c->c_arg);
959 KASSERT(!sq_locked, ("sleepqueue chain still locked"));
963 sleepq_release(&cc->cc_waiting);
965 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING);
967 if (cc->cc_next == c) {
968 cc->cc_next = TAILQ_NEXT(c, c_links.tqe);
970 TAILQ_REMOVE(&cc->cc_callwheel[c->c_time & callwheelmask], c,
973 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
974 c, c->c_func, c->c_arg);
976 if (c->c_flags & CALLOUT_LOCAL_ALLOC) {
978 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle);
985 callout_init(c, mpsafe)
992 c->c_flags = CALLOUT_RETURNUNLOCKED;
994 c->c_lock = &Giant.lock_object;
997 c->c_cpu = timeout_cpu;
1001 _callout_init_lock(c, lock, flags)
1003 struct lock_object *lock;
1006 bzero(c, sizeof *c);
1008 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0,
1009 ("callout_init_lock: bad flags %d", flags));
1010 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0,
1011 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock"));
1012 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags &
1013 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class",
1015 c->c_flags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK);
1016 c->c_cpu = timeout_cpu;
1019 #ifdef APM_FIXUP_CALLTODO
1021 * Adjust the kernel calltodo timeout list. This routine is used after
1022 * an APM resume to recalculate the calltodo timer list values with the
1023 * number of hz's we have been sleeping. The next hardclock() will detect
1024 * that there are fired timers and run softclock() to execute them.
1026 * Please note, I have not done an exhaustive analysis of what code this
1027 * might break. I am motivated to have my select()'s and alarm()'s that
1028 * have expired during suspend firing upon resume so that the applications
1029 * which set the timer can do the maintanence the timer was for as close
1030 * as possible to the originally intended time. Testing this code for a
1031 * week showed that resuming from a suspend resulted in 22 to 25 timers
1032 * firing, which seemed independant on whether the suspend was 2 hours or
1033 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu>
1036 adjust_timeout_calltodo(time_change)
1037 struct timeval *time_change;
1039 register struct callout *p;
1040 unsigned long delta_ticks;
1043 * How many ticks were we asleep?
1044 * (stolen from tvtohz()).
1047 /* Don't do anything */
1048 if (time_change->tv_sec < 0)
1050 else if (time_change->tv_sec <= LONG_MAX / 1000000)
1051 delta_ticks = (time_change->tv_sec * 1000000 +
1052 time_change->tv_usec + (tick - 1)) / tick + 1;
1053 else if (time_change->tv_sec <= LONG_MAX / hz)
1054 delta_ticks = time_change->tv_sec * hz +
1055 (time_change->tv_usec + (tick - 1)) / tick + 1;
1057 delta_ticks = LONG_MAX;
1059 if (delta_ticks > INT_MAX)
1060 delta_ticks = INT_MAX;
1063 * Now rip through the timer calltodo list looking for timers
1067 /* don't collide with softclock() */
1069 for (p = calltodo.c_next; p != NULL; p = p->c_next) {
1070 p->c_time -= delta_ticks;
1072 /* Break if the timer had more time on it than delta_ticks */
1076 /* take back the ticks the timer didn't use (p->c_time <= 0) */
1077 delta_ticks = -p->c_time;
1083 #endif /* APM_FIXUP_CALLTODO */