/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1982, 1986, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 */ #include __FBSDID("$FreeBSD$"); #include "opt_callout_profiling.h" #include "opt_ddb.h" #include "opt_rss.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DDB #include #include #include #endif #ifdef SMP #include #endif DPCPU_DECLARE(sbintime_t, hardclocktime); SDT_PROVIDER_DEFINE(callout_execute); SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); #ifdef CALLOUT_PROFILING static int avg_depth; SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, "Average number of items examined per softclock call. Units = 1/1000"); static int avg_gcalls; SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, "Average number of Giant callouts made per softclock call. Units = 1/1000"); static int avg_lockcalls; SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, "Average number of lock callouts made per softclock call. Units = 1/1000"); static int avg_mpcalls; SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, "Average number of MP callouts made per softclock call. Units = 1/1000"); static int avg_depth_dir; SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, "Average number of direct callouts examined per callout_process call. " "Units = 1/1000"); static int avg_lockcalls_dir; SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " "callout_process call. Units = 1/1000"); static int avg_mpcalls_dir; SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 0, "Average number of MP direct callouts made per callout_process call. " "Units = 1/1000"); #endif static int ncallout; SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0, "Number of entries in callwheel and size of timeout() preallocation"); #ifdef RSS static int pin_default_swi = 1; static int pin_pcpu_swi = 1; #else static int pin_default_swi = 0; static int pin_pcpu_swi = 0; #endif SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi, 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)"); SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi, 0, "Pin the per-CPU swis (except PCPU 0, which is also default)"); /* * TODO: * allocate more timeout table slots when table overflows. */ static u_int __read_mostly callwheelsize; static u_int __read_mostly callwheelmask; /* * The callout cpu exec entities represent informations necessary for * describing the state of callouts currently running on the CPU and the ones * necessary for migrating callouts to the new callout cpu. In particular, * the first entry of the array cc_exec_entity holds informations for callout * running in SWI thread context, while the second one holds informations * for callout running directly from hardware interrupt context. * The cached informations are very important for deferring migration when * the migrating callout is already running. */ struct cc_exec { struct callout *cc_curr; callout_func_t *cc_drain; void *cc_last_func; void *cc_last_arg; #ifdef SMP callout_func_t *ce_migration_func; void *ce_migration_arg; sbintime_t ce_migration_time; sbintime_t ce_migration_prec; int ce_migration_cpu; #endif bool cc_cancel; bool cc_waiting; }; /* * There is one struct callout_cpu per cpu, holding all relevant * state for the callout processing thread on the individual CPU. */ struct callout_cpu { struct mtx_padalign cc_lock; struct cc_exec cc_exec_entity[2]; struct callout *cc_next; struct callout_list *cc_callwheel; struct callout_tailq cc_expireq; sbintime_t cc_firstevent; sbintime_t cc_lastscan; void *cc_cookie; u_int cc_bucket; u_int cc_inited; #ifdef KTR char cc_ktr_event_name[20]; #endif }; #define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION) #define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr #define cc_exec_last_func(cc, dir) cc->cc_exec_entity[dir].cc_last_func #define cc_exec_last_arg(cc, dir) cc->cc_exec_entity[dir].cc_last_arg #define cc_exec_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain #define cc_exec_next(cc) cc->cc_next #define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel #define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting #ifdef SMP #define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func #define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg #define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu #define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time #define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec struct callout_cpu cc_cpu[MAXCPU]; #define CPUBLOCK MAXCPU #define CC_CPU(cpu) (&cc_cpu[(cpu)]) #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) #else struct callout_cpu cc_cpu; #define CC_CPU(cpu) &cc_cpu #define CC_SELF() &cc_cpu #endif #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) static int __read_mostly cc_default_cpu; static void callout_cpu_init(struct callout_cpu *cc, int cpu); static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, #ifdef CALLOUT_PROFILING int *mpcalls, int *lockcalls, int *gcalls, #endif int direct); static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); /** * Locked by cc_lock: * cc_curr - If a callout is in progress, it is cc_curr. * If cc_curr is non-NULL, threads waiting in * callout_drain() will be woken up as soon as the * relevant callout completes. * cc_cancel - Changing to 1 with both callout_lock and cc_lock held * guarantees that the current callout will not run. * The softclock() function sets this to 0 before it * drops callout_lock to acquire c_lock, and it calls * the handler only if curr_cancelled is still 0 after * cc_lock is successfully acquired. * cc_waiting - If a thread is waiting in callout_drain(), then * callout_wait is nonzero. Set only when * cc_curr is non-NULL. */ /* * Resets the execution entity tied to a specific callout cpu. */ static void cc_cce_cleanup(struct callout_cpu *cc, int direct) { cc_exec_curr(cc, direct) = NULL; cc_exec_cancel(cc, direct) = false; cc_exec_waiting(cc, direct) = false; #ifdef SMP cc_migration_cpu(cc, direct) = CPUBLOCK; cc_migration_time(cc, direct) = 0; cc_migration_prec(cc, direct) = 0; cc_migration_func(cc, direct) = NULL; cc_migration_arg(cc, direct) = NULL; #endif } /* * Checks if migration is requested by a specific callout cpu. */ static int cc_cce_migrating(struct callout_cpu *cc, int direct) { #ifdef SMP return (cc_migration_cpu(cc, direct) != CPUBLOCK); #else return (0); #endif } /* * Kernel low level callwheel initialization * called on the BSP during kernel startup. */ static void callout_callwheel_init(void *dummy) { struct callout_cpu *cc; int cpu; /* * Calculate the size of the callout wheel and the preallocated * timeout() structures. * XXX: Clip callout to result of previous function of maxusers * maximum 384. This is still huge, but acceptable. */ ncallout = imin(16 + maxproc + maxfiles, 18508); TUNABLE_INT_FETCH("kern.ncallout", &ncallout); /* * Calculate callout wheel size, should be next power of two higher * than 'ncallout'. */ callwheelsize = 1 << fls(ncallout); callwheelmask = callwheelsize - 1; /* * Fetch whether we're pinning the swi's or not. */ TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); /* * Initialize callout wheels. The software interrupt threads * are created later. */ cc_default_cpu = PCPU_GET(cpuid); CPU_FOREACH(cpu) { cc = CC_CPU(cpu); callout_cpu_init(cc, cpu); } } SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); /* * Initialize the per-cpu callout structures. */ static void callout_cpu_init(struct callout_cpu *cc, int cpu) { int i; mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); cc->cc_inited = 1; cc->cc_callwheel = malloc_domainset(sizeof(struct callout_list) * callwheelsize, M_CALLOUT, DOMAINSET_PREF(pcpu_find(cpu)->pc_domain), M_WAITOK); for (i = 0; i < callwheelsize; i++) LIST_INIT(&cc->cc_callwheel[i]); TAILQ_INIT(&cc->cc_expireq); cc->cc_firstevent = SBT_MAX; for (i = 0; i < 2; i++) cc_cce_cleanup(cc, i); #ifdef KTR snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), "callwheel cpu %d", cpu); #endif } #ifdef SMP /* * Switches the cpu tied to a specific callout. * The function expects a locked incoming callout cpu and returns with * locked outcoming callout cpu. */ static struct callout_cpu * callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) { struct callout_cpu *new_cc; MPASS(c != NULL && cc != NULL); CC_LOCK_ASSERT(cc); /* * Avoid interrupts and preemption firing after the callout cpu * is blocked in order to avoid deadlocks as the new thread * may be willing to acquire the callout cpu lock. */ c->c_cpu = CPUBLOCK; spinlock_enter(); CC_UNLOCK(cc); new_cc = CC_CPU(new_cpu); CC_LOCK(new_cc); spinlock_exit(); c->c_cpu = new_cpu; return (new_cc); } #endif /* * Start softclock threads. */ static void start_softclock(void *dummy) { struct callout_cpu *cc; char name[MAXCOMLEN]; int cpu; bool pin_swi; struct intr_event *ie; CPU_FOREACH(cpu) { cc = CC_CPU(cpu); snprintf(name, sizeof(name), "clock (%d)", cpu); ie = NULL; if (swi_add(&ie, name, softclock, cc, SWI_CLOCK, INTR_MPSAFE, &cc->cc_cookie)) panic("died while creating standard software ithreads"); if (cpu == cc_default_cpu) pin_swi = pin_default_swi; else pin_swi = pin_pcpu_swi; if (pin_swi && (intr_event_bind(ie, cpu) != 0)) { printf("%s: %s clock couldn't be pinned to cpu %d\n", __func__, cpu == cc_default_cpu ? "default" : "per-cpu", cpu); } } } SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); #define CC_HASH_SHIFT 8 static inline u_int callout_hash(sbintime_t sbt) { return (sbt >> (32 - CC_HASH_SHIFT)); } static inline u_int callout_get_bucket(sbintime_t sbt) { return (callout_hash(sbt) & callwheelmask); } void callout_process(sbintime_t now) { struct callout *tmp, *tmpn; struct callout_cpu *cc; struct callout_list *sc; sbintime_t first, last, max, tmp_max; uint32_t lookahead; u_int firstb, lastb, nowb; #ifdef CALLOUT_PROFILING int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; #endif cc = CC_SELF(); mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); /* Compute the buckets of the last scan and present times. */ firstb = callout_hash(cc->cc_lastscan); cc->cc_lastscan = now; nowb = callout_hash(now); /* Compute the last bucket and minimum time of the bucket after it. */ if (nowb == firstb) lookahead = (SBT_1S / 16); else if (nowb - firstb == 1) lookahead = (SBT_1S / 8); else lookahead = (SBT_1S / 2); first = last = now; first += (lookahead / 2); last += lookahead; last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); lastb = callout_hash(last) - 1; max = last; /* * Check if we wrapped around the entire wheel from the last scan. * In case, we need to scan entirely the wheel for pending callouts. */ if (lastb - firstb >= callwheelsize) { lastb = firstb + callwheelsize - 1; if (nowb - firstb >= callwheelsize) nowb = lastb; } /* Iterate callwheel from firstb to nowb and then up to lastb. */ do { sc = &cc->cc_callwheel[firstb & callwheelmask]; tmp = LIST_FIRST(sc); while (tmp != NULL) { /* Run the callout if present time within allowed. */ if (tmp->c_time <= now) { /* * Consumer told us the callout may be run * directly from hardware interrupt context. */ if (tmp->c_iflags & CALLOUT_DIRECT) { #ifdef CALLOUT_PROFILING ++depth_dir; #endif cc_exec_next(cc) = LIST_NEXT(tmp, c_links.le); cc->cc_bucket = firstb & callwheelmask; LIST_REMOVE(tmp, c_links.le); softclock_call_cc(tmp, cc, #ifdef CALLOUT_PROFILING &mpcalls_dir, &lockcalls_dir, NULL, #endif 1); tmp = cc_exec_next(cc); cc_exec_next(cc) = NULL; } else { tmpn = LIST_NEXT(tmp, c_links.le); LIST_REMOVE(tmp, c_links.le); TAILQ_INSERT_TAIL(&cc->cc_expireq, tmp, c_links.tqe); tmp->c_iflags |= CALLOUT_PROCESSED; tmp = tmpn; } continue; } /* Skip events from distant future. */ if (tmp->c_time >= max) goto next; /* * Event minimal time is bigger than present maximal * time, so it cannot be aggregated. */ if (tmp->c_time > last) { lastb = nowb; goto next; } /* Update first and last time, respecting this event. */ if (tmp->c_time < first) first = tmp->c_time; tmp_max = tmp->c_time + tmp->c_precision; if (tmp_max < last) last = tmp_max; next: tmp = LIST_NEXT(tmp, c_links.le); } /* Proceed with the next bucket. */ firstb++; /* * Stop if we looked after present time and found * some event we can't execute at now. * Stop if we looked far enough into the future. */ } while (((int)(firstb - lastb)) <= 0); cc->cc_firstevent = last; cpu_new_callout(curcpu, last, first); #ifdef CALLOUT_PROFILING avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; #endif mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); /* * swi_sched acquires the thread lock, so we don't want to call it * with cc_lock held; incorrect locking order. */ if (!TAILQ_EMPTY(&cc->cc_expireq)) swi_sched(cc->cc_cookie, 0); } static struct callout_cpu * callout_lock(struct callout *c) { struct callout_cpu *cc; int cpu; for (;;) { cpu = c->c_cpu; #ifdef SMP if (cpu == CPUBLOCK) { while (c->c_cpu == CPUBLOCK) cpu_spinwait(); continue; } #endif cc = CC_CPU(cpu); CC_LOCK(cc); if (cpu == c->c_cpu) break; CC_UNLOCK(cc); } return (cc); } static void callout_cc_add(struct callout *c, struct callout_cpu *cc, sbintime_t sbt, sbintime_t precision, void (*func)(void *), void *arg, int cpu, int flags) { int bucket; CC_LOCK_ASSERT(cc); if (sbt < cc->cc_lastscan) sbt = cc->cc_lastscan; c->c_arg = arg; c->c_iflags |= CALLOUT_PENDING; c->c_iflags &= ~CALLOUT_PROCESSED; c->c_flags |= CALLOUT_ACTIVE; if (flags & C_DIRECT_EXEC) c->c_iflags |= CALLOUT_DIRECT; c->c_func = func; c->c_time = sbt; c->c_precision = precision; bucket = callout_get_bucket(c->c_time); CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", c, (int)(c->c_precision >> 32), (u_int)(c->c_precision & 0xffffffff)); LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); if (cc->cc_bucket == bucket) cc_exec_next(cc) = c; /* * Inform the eventtimers(4) subsystem there's a new callout * that has been inserted, but only if really required. */ if (SBT_MAX - c->c_time < c->c_precision) c->c_precision = SBT_MAX - c->c_time; sbt = c->c_time + c->c_precision; if (sbt < cc->cc_firstevent) { cc->cc_firstevent = sbt; cpu_new_callout(cpu, sbt, c->c_time); } } static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, #ifdef CALLOUT_PROFILING int *mpcalls, int *lockcalls, int *gcalls, #endif int direct) { struct rm_priotracker tracker; callout_func_t *c_func, *drain; void *c_arg; struct lock_class *class; struct lock_object *c_lock; uintptr_t lock_status; int c_iflags; #ifdef SMP struct callout_cpu *new_cc; callout_func_t *new_func; void *new_arg; int flags, new_cpu; sbintime_t new_prec, new_time; #endif #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) sbintime_t sbt1, sbt2; struct timespec ts2; static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ static callout_func_t *lastfunc; #endif KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, ("softclock_call_cc: pend %p %x", c, c->c_iflags)); KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, ("softclock_call_cc: act %p %x", c, c->c_flags)); class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; lock_status = 0; if (c->c_flags & CALLOUT_SHAREDLOCK) { if (class == &lock_class_rm) lock_status = (uintptr_t)&tracker; else lock_status = 1; } c_lock = c->c_lock; c_func = c->c_func; c_arg = c->c_arg; c_iflags = c->c_iflags; c->c_iflags &= ~CALLOUT_PENDING; cc_exec_curr(cc, direct) = c; cc_exec_last_func(cc, direct) = c_func; cc_exec_last_arg(cc, direct) = c_arg; cc_exec_cancel(cc, direct) = false; cc_exec_drain(cc, direct) = NULL; CC_UNLOCK(cc); if (c_lock != NULL) { class->lc_lock(c_lock, lock_status); /* * The callout may have been cancelled * while we switched locks. */ if (cc_exec_cancel(cc, direct)) { class->lc_unlock(c_lock); goto skip; } /* The callout cannot be stopped now. */ cc_exec_cancel(cc, direct) = true; if (c_lock == &Giant.lock_object) { #ifdef CALLOUT_PROFILING (*gcalls)++; #endif CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", c, c_func, c_arg); } else { #ifdef CALLOUT_PROFILING (*lockcalls)++; #endif CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", c, c_func, c_arg); } } else { #ifdef CALLOUT_PROFILING (*mpcalls)++; #endif CTR3(KTR_CALLOUT, "callout %p func %p arg %p", c, c_func, c_arg); } KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) sbt1 = sbinuptime(); #endif THREAD_NO_SLEEPING(); SDT_PROBE1(callout_execute, , , callout__start, c); c_func(c_arg); SDT_PROBE1(callout_execute, , , callout__end, c); THREAD_SLEEPING_OK(); #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) sbt2 = sbinuptime(); sbt2 -= sbt1; if (sbt2 > maxdt) { if (lastfunc != c_func || sbt2 > maxdt * 2) { ts2 = sbttots(sbt2); printf( "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); } maxdt = sbt2; lastfunc = c_func; } #endif KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); CTR1(KTR_CALLOUT, "callout %p finished", c); if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) class->lc_unlock(c_lock); skip: CC_LOCK(cc); KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); cc_exec_curr(cc, direct) = NULL; if (cc_exec_drain(cc, direct)) { drain = cc_exec_drain(cc, direct); cc_exec_drain(cc, direct) = NULL; CC_UNLOCK(cc); drain(c_arg); CC_LOCK(cc); } if (cc_exec_waiting(cc, direct)) { /* * There is someone waiting for the * callout to complete. * If the callout was scheduled for * migration just cancel it. */ if (cc_cce_migrating(cc, direct)) { cc_cce_cleanup(cc, direct); /* * It should be assert here that the callout is not * destroyed but that is not easy. */ c->c_iflags &= ~CALLOUT_DFRMIGRATION; } cc_exec_waiting(cc, direct) = false; CC_UNLOCK(cc); wakeup(&cc_exec_waiting(cc, direct)); CC_LOCK(cc); } else if (cc_cce_migrating(cc, direct)) { #ifdef SMP /* * If the callout was scheduled for * migration just perform it now. */ new_cpu = cc_migration_cpu(cc, direct); new_time = cc_migration_time(cc, direct); new_prec = cc_migration_prec(cc, direct); new_func = cc_migration_func(cc, direct); new_arg = cc_migration_arg(cc, direct); cc_cce_cleanup(cc, direct); /* * It should be assert here that the callout is not destroyed * but that is not easy. * * As first thing, handle deferred callout stops. */ if (!callout_migrating(c)) { CTR3(KTR_CALLOUT, "deferred cancelled %p func %p arg %p", c, new_func, new_arg); return; } c->c_iflags &= ~CALLOUT_DFRMIGRATION; new_cc = callout_cpu_switch(c, cc, new_cpu); flags = (direct) ? C_DIRECT_EXEC : 0; callout_cc_add(c, new_cc, new_time, new_prec, new_func, new_arg, new_cpu, flags); CC_UNLOCK(new_cc); CC_LOCK(cc); #else panic("migration should not happen"); #endif } } /* * The callout mechanism is based on the work of Adam M. Costello and * George Varghese, published in a technical report entitled "Redesigning * the BSD Callout and Timer Facilities" and modified slightly for inclusion * in FreeBSD by Justin T. Gibbs. The original work on the data structures * used in this implementation was published by G. Varghese and T. Lauck in * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for * the Efficient Implementation of a Timer Facility" in the Proceedings of * the 11th ACM Annual Symposium on Operating Systems Principles, * Austin, Texas Nov 1987. */ /* * Software (low priority) clock interrupt. * Run periodic events from timeout queue. */ void softclock(void *arg) { struct callout_cpu *cc; struct callout *c; #ifdef CALLOUT_PROFILING int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; #endif cc = (struct callout_cpu *)arg; CC_LOCK(cc); while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); softclock_call_cc(c, cc, #ifdef CALLOUT_PROFILING &mpcalls, &lockcalls, &gcalls, #endif 0); #ifdef CALLOUT_PROFILING ++depth; #endif } #ifdef CALLOUT_PROFILING avg_depth += (depth * 1000 - avg_depth) >> 8; avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; #endif CC_UNLOCK(cc); } void callout_when(sbintime_t sbt, sbintime_t precision, int flags, sbintime_t *res, sbintime_t *prec_res) { sbintime_t to_sbt, to_pr; if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) { *res = sbt; *prec_res = precision; return; } if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt) sbt = tick_sbt; if ((flags & C_HARDCLOCK) != 0 || sbt >= sbt_tickthreshold) { /* * Obtain the time of the last hardclock() call on * this CPU directly from the kern_clocksource.c. * This value is per-CPU, but it is equal for all * active ones. */ #ifdef __LP64__ to_sbt = DPCPU_GET(hardclocktime); #else spinlock_enter(); to_sbt = DPCPU_GET(hardclocktime); spinlock_exit(); #endif if (cold && to_sbt == 0) to_sbt = sbinuptime(); if ((flags & C_HARDCLOCK) == 0) to_sbt += tick_sbt; } else to_sbt = sbinuptime(); if (SBT_MAX - to_sbt < sbt) to_sbt = SBT_MAX; else to_sbt += sbt; *res = to_sbt; to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : sbt >> C_PRELGET(flags)); *prec_res = to_pr > precision ? to_pr : precision; } /* * New interface; clients allocate their own callout structures. * * callout_reset() - establish or change a timeout * callout_stop() - disestablish a timeout * callout_init() - initialize a callout structure so that it can * safely be passed to callout_reset() and callout_stop() * * defines three convenience macros: * * callout_active() - returns truth if callout has not been stopped, * drained, or deactivated since the last time the callout was * reset. * callout_pending() - returns truth if callout is still waiting for timeout * callout_deactivate() - marks the callout as having been serviced */ int callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec, callout_func_t *ftn, void *arg, int cpu, int flags) { sbintime_t to_sbt, precision; struct callout_cpu *cc; int cancelled, direct; int ignore_cpu=0; cancelled = 0; if (cpu == -1) { ignore_cpu = 1; } else if ((cpu >= MAXCPU) || ((CC_CPU(cpu))->cc_inited == 0)) { /* Invalid CPU spec */ panic("Invalid CPU in callout %d", cpu); } callout_when(sbt, prec, flags, &to_sbt, &precision); /* * This flag used to be added by callout_cc_add, but the * first time you call this we could end up with the * wrong direct flag if we don't do it before we add. */ if (flags & C_DIRECT_EXEC) { direct = 1; } else { direct = 0; } KASSERT(!direct || c->c_lock == NULL, ("%s: direct callout %p has lock", __func__, c)); cc = callout_lock(c); /* * Don't allow migration if the user does not care. */ if (ignore_cpu) { cpu = c->c_cpu; } if (cc_exec_curr(cc, direct) == c) { /* * We're being asked to reschedule a callout which is * currently in progress. If there is a lock then we * can cancel the callout if it has not really started. */ if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) cancelled = cc_exec_cancel(cc, direct) = true; if (cc_exec_waiting(cc, direct) || cc_exec_drain(cc, direct)) { /* * Someone has called callout_drain to kill this * callout. Don't reschedule. */ CTR4(KTR_CALLOUT, "%s %p func %p arg %p", cancelled ? "cancelled" : "failed to cancel", c, c->c_func, c->c_arg); CC_UNLOCK(cc); return (cancelled); } #ifdef SMP if (callout_migrating(c)) { /* * This only occurs when a second callout_reset_sbt_on * is made after a previous one moved it into * deferred migration (below). Note we do *not* change * the prev_cpu even though the previous target may * be different. */ cc_migration_cpu(cc, direct) = cpu; cc_migration_time(cc, direct) = to_sbt; cc_migration_prec(cc, direct) = precision; cc_migration_func(cc, direct) = ftn; cc_migration_arg(cc, direct) = arg; cancelled = 1; CC_UNLOCK(cc); return (cancelled); } #endif } if (c->c_iflags & CALLOUT_PENDING) { if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { if (cc_exec_next(cc) == c) cc_exec_next(cc) = LIST_NEXT(c, c_links.le); LIST_REMOVE(c, c_links.le); } else { TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); } cancelled = 1; c->c_iflags &= ~ CALLOUT_PENDING; c->c_flags &= ~ CALLOUT_ACTIVE; } #ifdef SMP /* * If the callout must migrate try to perform it immediately. * If the callout is currently running, just defer the migration * to a more appropriate moment. */ if (c->c_cpu != cpu) { if (cc_exec_curr(cc, direct) == c) { /* * Pending will have been removed since we are * actually executing the callout on another * CPU. That callout should be waiting on the * lock the caller holds. If we set both * active/and/pending after we return and the * lock on the executing callout proceeds, it * will then see pending is true and return. * At the return from the actual callout execution * the migration will occur in softclock_call_cc * and this new callout will be placed on the * new CPU via a call to callout_cpu_switch() which * will get the lock on the right CPU followed * by a call callout_cc_add() which will add it there. * (see above in softclock_call_cc()). */ cc_migration_cpu(cc, direct) = cpu; cc_migration_time(cc, direct) = to_sbt; cc_migration_prec(cc, direct) = precision; cc_migration_func(cc, direct) = ftn; cc_migration_arg(cc, direct) = arg; c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); c->c_flags |= CALLOUT_ACTIVE; CTR6(KTR_CALLOUT, "migration of %p func %p arg %p in %d.%08x to %u deferred", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), (u_int)(to_sbt & 0xffffffff), cpu); CC_UNLOCK(cc); return (cancelled); } cc = callout_cpu_switch(c, cc, cpu); } #endif callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), (u_int)(to_sbt & 0xffffffff)); CC_UNLOCK(cc); return (cancelled); } /* * Common idioms that can be optimized in the future. */ int callout_schedule_on(struct callout *c, int to_ticks, int cpu) { return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); } int callout_schedule(struct callout *c, int to_ticks) { return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); } int _callout_stop_safe(struct callout *c, int flags, callout_func_t *drain) { struct callout_cpu *cc, *old_cc; struct lock_class *class; int direct, sq_locked, use_lock; int cancelled, not_on_a_list; if ((flags & CS_DRAIN) != 0) WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, "calling %s", __func__); KASSERT((flags & CS_DRAIN) == 0 || drain == NULL, ("Cannot set drain callback and CS_DRAIN flag at the same time")); /* * Some old subsystems don't hold Giant while running a callout_stop(), * so just discard this check for the moment. */ if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { if (c->c_lock == &Giant.lock_object) use_lock = mtx_owned(&Giant); else { use_lock = 1; class = LOCK_CLASS(c->c_lock); class->lc_assert(c->c_lock, LA_XLOCKED); } } else use_lock = 0; if (c->c_iflags & CALLOUT_DIRECT) { direct = 1; } else { direct = 0; } sq_locked = 0; old_cc = NULL; again: cc = callout_lock(c); if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { /* * Special case where this slipped in while we * were migrating *as* the callout is about to * execute. The caller probably holds the lock * the callout wants. * * Get rid of the migration first. Then set * the flag that tells this code *not* to * try to remove it from any lists (its not * on one yet). When the callout wheel runs, * it will ignore this callout. */ c->c_iflags &= ~CALLOUT_PENDING; c->c_flags &= ~CALLOUT_ACTIVE; not_on_a_list = 1; } else { not_on_a_list = 0; } /* * If the callout was migrating while the callout cpu lock was * dropped, just drop the sleepqueue lock and check the states * again. */ if (sq_locked != 0 && cc != old_cc) { #ifdef SMP CC_UNLOCK(cc); sleepq_release(&cc_exec_waiting(old_cc, direct)); sq_locked = 0; old_cc = NULL; goto again; #else panic("migration should not happen"); #endif } /* * If the callout is running, try to stop it or drain it. */ if (cc_exec_curr(cc, direct) == c) { /* * Succeed we to stop it or not, we must clear the * active flag - this is what API users expect. If we're * draining and the callout is currently executing, first wait * until it finishes. */ if ((flags & CS_DRAIN) == 0) c->c_flags &= ~CALLOUT_ACTIVE; if ((flags & CS_DRAIN) != 0) { /* * The current callout is running (or just * about to run) and blocking is allowed, so * just wait for the current invocation to * finish. */ if (cc_exec_curr(cc, direct) == c) { /* * Use direct calls to sleepqueue interface * instead of cv/msleep in order to avoid * a LOR between cc_lock and sleepqueue * chain spinlocks. This piece of code * emulates a msleep_spin() call actually. * * If we already have the sleepqueue chain * locked, then we can safely block. If we * don't already have it locked, however, * we have to drop the cc_lock to lock * it. This opens several races, so we * restart at the beginning once we have * both locks. If nothing has changed, then * we will end up back here with sq_locked * set. */ if (!sq_locked) { CC_UNLOCK(cc); sleepq_lock( &cc_exec_waiting(cc, direct)); sq_locked = 1; old_cc = cc; goto again; } /* * Migration could be cancelled here, but * as long as it is still not sure when it * will be packed up, just let softclock() * take care of it. */ cc_exec_waiting(cc, direct) = true; DROP_GIANT(); CC_UNLOCK(cc); sleepq_add( &cc_exec_waiting(cc, direct), &cc->cc_lock.lock_object, "codrain", SLEEPQ_SLEEP, 0); sleepq_wait( &cc_exec_waiting(cc, direct), 0); sq_locked = 0; old_cc = NULL; /* Reacquire locks previously released. */ PICKUP_GIANT(); goto again; } c->c_flags &= ~CALLOUT_ACTIVE; } else if (use_lock && !cc_exec_cancel(cc, direct) && (drain == NULL)) { /* * The current callout is waiting for its * lock which we hold. Cancel the callout * and return. After our caller drops the * lock, the callout will be skipped in * softclock(). This *only* works with a * callout_stop() *not* callout_drain() or * callout_async_drain(). */ cc_exec_cancel(cc, direct) = true; CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", c, c->c_func, c->c_arg); KASSERT(!cc_cce_migrating(cc, direct), ("callout wrongly scheduled for migration")); if (callout_migrating(c)) { c->c_iflags &= ~CALLOUT_DFRMIGRATION; #ifdef SMP cc_migration_cpu(cc, direct) = CPUBLOCK; cc_migration_time(cc, direct) = 0; cc_migration_prec(cc, direct) = 0; cc_migration_func(cc, direct) = NULL; cc_migration_arg(cc, direct) = NULL; #endif } CC_UNLOCK(cc); KASSERT(!sq_locked, ("sleepqueue chain locked")); return (1); } else if (callout_migrating(c)) { /* * The callout is currently being serviced * and the "next" callout is scheduled at * its completion with a migration. We remove * the migration flag so it *won't* get rescheduled, * but we can't stop the one thats running so * we return 0. */ c->c_iflags &= ~CALLOUT_DFRMIGRATION; #ifdef SMP /* * We can't call cc_cce_cleanup here since * if we do it will remove .ce_curr and * its still running. This will prevent a * reschedule of the callout when the * execution completes. */ cc_migration_cpu(cc, direct) = CPUBLOCK; cc_migration_time(cc, direct) = 0; cc_migration_prec(cc, direct) = 0; cc_migration_func(cc, direct) = NULL; cc_migration_arg(cc, direct) = NULL; #endif CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", c, c->c_func, c->c_arg); if (drain) { KASSERT(cc_exec_drain(cc, direct) == NULL, ("callout drain function already set to %p", cc_exec_drain(cc, direct))); cc_exec_drain(cc, direct) = drain; } CC_UNLOCK(cc); return ((flags & CS_EXECUTING) != 0); } else { CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", c, c->c_func, c->c_arg); if (drain) { KASSERT(cc_exec_drain(cc, direct) == NULL, ("callout drain function already set to %p", cc_exec_drain(cc, direct))); cc_exec_drain(cc, direct) = drain; } } KASSERT(!sq_locked, ("sleepqueue chain still locked")); cancelled = ((flags & CS_EXECUTING) != 0); } else cancelled = 1; if (sq_locked) sleepq_release(&cc_exec_waiting(cc, direct)); if ((c->c_iflags & CALLOUT_PENDING) == 0) { CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", c, c->c_func, c->c_arg); /* * For not scheduled and not executing callout return * negative value. */ if (cc_exec_curr(cc, direct) != c) cancelled = -1; CC_UNLOCK(cc); return (cancelled); } c->c_iflags &= ~CALLOUT_PENDING; c->c_flags &= ~CALLOUT_ACTIVE; CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", c, c->c_func, c->c_arg); if (not_on_a_list == 0) { if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { if (cc_exec_next(cc) == c) cc_exec_next(cc) = LIST_NEXT(c, c_links.le); LIST_REMOVE(c, c_links.le); } else { TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); } } CC_UNLOCK(cc); return (cancelled); } void callout_init(struct callout *c, int mpsafe) { bzero(c, sizeof *c); if (mpsafe) { c->c_lock = NULL; c->c_iflags = CALLOUT_RETURNUNLOCKED; } else { c->c_lock = &Giant.lock_object; c->c_iflags = 0; } c->c_cpu = cc_default_cpu; } void _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) { bzero(c, sizeof *c); c->c_lock = lock; KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, ("callout_init_lock: bad flags %d", flags)); KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", __func__)); c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); c->c_cpu = cc_default_cpu; } static int flssbt(sbintime_t sbt) { sbt += (uint64_t)sbt >> 1; if (sizeof(long) >= sizeof(sbintime_t)) return (flsl(sbt)); if (sbt >= SBT_1S) return (flsl(((uint64_t)sbt) >> 32) + 32); return (flsl(sbt)); } /* * Dump immediate statistic snapshot of the scheduled callouts. */ static int sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) { struct callout *tmp; struct callout_cpu *cc; struct callout_list *sc; sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; int ct[64], cpr[64], ccpbk[32]; int error, val, i, count, tcum, pcum, maxc, c, medc; int cpu; val = 0; error = sysctl_handle_int(oidp, &val, 0, req); if (error != 0 || req->newptr == NULL) return (error); count = maxc = 0; st = spr = maxt = maxpr = 0; bzero(ccpbk, sizeof(ccpbk)); bzero(ct, sizeof(ct)); bzero(cpr, sizeof(cpr)); now = sbinuptime(); CPU_FOREACH(cpu) { cc = CC_CPU(cpu); CC_LOCK(cc); for (i = 0; i < callwheelsize; i++) { sc = &cc->cc_callwheel[i]; c = 0; LIST_FOREACH(tmp, sc, c_links.le) { c++; t = tmp->c_time - now; if (t < 0) t = 0; st += t / SBT_1US; spr += tmp->c_precision / SBT_1US; if (t > maxt) maxt = t; if (tmp->c_precision > maxpr) maxpr = tmp->c_precision; ct[flssbt(t)]++; cpr[flssbt(tmp->c_precision)]++; } if (c > maxc) maxc = c; ccpbk[fls(c + c / 2)]++; count += c; } CC_UNLOCK(cc); } for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) tcum += ct[i]; medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) pcum += cpr[i]; medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; for (i = 0, c = 0; i < 32 && c < count / 2; i++) c += ccpbk[i]; medc = (i >= 2) ? (1 << (i - 2)) : 0; printf("Scheduled callouts statistic snapshot:\n"); printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", medc, count / callwheelsize / mp_ncpus, (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, maxc); printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, (st / count) / 1000000, (st / count) % 1000000, maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, (spr / count) / 1000000, (spr / count) % 1000000, maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); printf(" Distribution: \tbuckets\t time\t tcum\t" " prec\t pcum\n"); for (i = 0, tcum = pcum = 0; i < 64; i++) { if (ct[i] == 0 && cpr[i] == 0) continue; t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; tcum += ct[i]; pcum += cpr[i]; printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, i - 1 - (32 - CC_HASH_SHIFT), ct[i], tcum, cpr[i], pcum); } return (error); } SYSCTL_PROC(_kern, OID_AUTO, callout_stat, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0, sysctl_kern_callout_stat, "I", "Dump immediate statistic snapshot of the scheduled callouts"); #ifdef DDB static void _show_callout(struct callout *c) { db_printf("callout %p\n", c); #define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e); db_printf(" &c_links = %p\n", &(c->c_links)); C_DB_PRINTF("%" PRId64, c_time); C_DB_PRINTF("%" PRId64, c_precision); C_DB_PRINTF("%p", c_arg); C_DB_PRINTF("%p", c_func); C_DB_PRINTF("%p", c_lock); C_DB_PRINTF("%#x", c_flags); C_DB_PRINTF("%#x", c_iflags); C_DB_PRINTF("%d", c_cpu); #undef C_DB_PRINTF } DB_SHOW_COMMAND(callout, db_show_callout) { if (!have_addr) { db_printf("usage: show callout \n"); return; } _show_callout((struct callout *)addr); } static void _show_last_callout(int cpu, int direct, const char *dirstr) { struct callout_cpu *cc; void *func, *arg; cc = CC_CPU(cpu); func = cc_exec_last_func(cc, direct); arg = cc_exec_last_arg(cc, direct); db_printf("cpu %d last%s callout function: %p ", cpu, dirstr, func); db_printsym((db_expr_t)func, DB_STGY_ANY); db_printf("\ncpu %d last%s callout argument: %p\n", cpu, dirstr, arg); } DB_SHOW_COMMAND(callout_last, db_show_callout_last) { int cpu, last; if (have_addr) { if (addr < 0 || addr > mp_maxid || CPU_ABSENT(addr)) { db_printf("no such cpu: %d\n", (int)addr); return; } cpu = last = addr; } else { cpu = 0; last = mp_maxid; } while (cpu <= last) { if (!CPU_ABSENT(cpu)) { _show_last_callout(cpu, 0, ""); _show_last_callout(cpu, 1, " direct"); } cpu++; } } #endif /* DDB */