kern_timeout.c revision 139831
11541Srgrimes/*- 21541Srgrimes * Copyright (c) 1982, 1986, 1991, 1993 31541Srgrimes * The Regents of the University of California. All rights reserved. 41541Srgrimes * (c) UNIX System Laboratories, Inc. 51541Srgrimes * All or some portions of this file are derived from material licensed 61541Srgrimes * to the University of California by American Telephone and Telegraph 71541Srgrimes * Co. or Unix System Laboratories, Inc. and are reproduced herein with 81541Srgrimes * the permission of UNIX System Laboratories, Inc. 91541Srgrimes * 101541Srgrimes * Redistribution and use in source and binary forms, with or without 111541Srgrimes * modification, are permitted provided that the following conditions 121541Srgrimes * are met: 131541Srgrimes * 1. Redistributions of source code must retain the above copyright 141541Srgrimes * notice, this list of conditions and the following disclaimer. 151541Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 161541Srgrimes * notice, this list of conditions and the following disclaimer in the 171541Srgrimes * documentation and/or other materials provided with the distribution. 181541Srgrimes * 4. Neither the name of the University nor the names of its contributors 191541Srgrimes * may be used to endorse or promote products derived from this software 201541Srgrimes * without specific prior written permission. 211541Srgrimes * 221541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 231541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 241541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 251541Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 261541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 271541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 281541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 291541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 301541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 311541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 321541Srgrimes * SUCH DAMAGE. 331541Srgrimes * 3444510Swollman * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 351541Srgrimes */ 361541Srgrimes 37116182Sobrien#include <sys/cdefs.h> 38116182Sobrien__FBSDID("$FreeBSD: head/sys/kern/kern_timeout.c 139831 2005-01-07 03:25:45Z cperciva $"); 39116182Sobrien 401541Srgrimes#include <sys/param.h> 411541Srgrimes#include <sys/systm.h> 4233392Sphk#include <sys/callout.h> 43127969Scperciva#include <sys/condvar.h> 441541Srgrimes#include <sys/kernel.h> 45133229Srwatson#include <sys/ktr.h> 4674914Sjhb#include <sys/lock.h> 4768840Sjhb#include <sys/mutex.h> 48115810Sphk#include <sys/sysctl.h> 491541Srgrimes 50115810Sphkstatic int avg_depth; 51115810SphkSYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 52115810Sphk "Average number of items examined per softclock call. Units = 1/1000"); 53115810Sphkstatic int avg_gcalls; 54115810SphkSYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 55115810Sphk "Average number of Giant callouts made per softclock call. Units = 1/1000"); 56115810Sphkstatic int avg_mpcalls; 57115810SphkSYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 58115810Sphk "Average number of MP callouts made per softclock call. Units = 1/1000"); 5933392Sphk/* 6033392Sphk * TODO: 6133392Sphk * allocate more timeout table slots when table overflows. 6233392Sphk */ 6333392Sphk 6433392Sphk/* Exported to machdep.c and/or kern_clock.c. */ 6529680Sgibbsstruct callout *callout; 6629680Sgibbsstruct callout_list callfree; 6729680Sgibbsint callwheelsize, callwheelbits, callwheelmask; 6829680Sgibbsstruct callout_tailq *callwheel; 6933392Sphkint softticks; /* Like ticks, but for softclock(). */ 70116606Sphkstruct mtx callout_lock; 71122585Smckusick#ifdef DIAGNOSTIC 72122761Sphkstruct mtx dont_sleep_in_callout; 73122585Smckusick#endif 742112Swollman 7529680Sgibbsstatic struct callout *nextsoftcheck; /* Next callout to be checked. */ 76128024Scperciva 77139831Scperciva/** 78127969Scperciva * Locked by callout_lock: 79127969Scperciva * curr_callout - If a callout is in progress, it is curr_callout. 80127969Scperciva * If curr_callout is non-NULL, threads waiting on 81127969Scperciva * callout_wait will be woken up as soon as the 82127969Scperciva * relevant callout completes. 83128024Scperciva * wakeup_ctr - Incremented every time a thread wants to wait 84128024Scperciva * for a callout to complete. Modified only when 85128024Scperciva * curr_callout is non-NULL. 86127969Scperciva * wakeup_needed - If a thread is waiting on callout_wait, then 87127969Scperciva * wakeup_needed is nonzero. Increased only when 88127969Scperciva * cutt_callout is non-NULL. 89127969Scperciva */ 90127969Scpercivastatic struct callout *curr_callout; 91128024Scpercivastatic int wakeup_ctr; 92127969Scpercivastatic int wakeup_needed; 93128024Scperciva 94139831Scperciva/** 95127969Scperciva * Locked by callout_wait_lock: 96127969Scperciva * callout_wait - If wakeup_needed is set, callout_wait will be 97127969Scperciva * triggered after the current callout finishes. 98127969Scperciva * wakeup_done_ctr - Set to the current value of wakeup_ctr after 99127969Scperciva * callout_wait is triggered. 100127969Scperciva */ 101127969Scpercivastatic struct mtx callout_wait_lock; 102127969Scpercivastatic struct cv callout_wait; 103127969Scpercivastatic int wakeup_done_ctr; 1041541Srgrimes 1051541Srgrimes/* 10682127Sdillon * kern_timeout_callwheel_alloc() - kernel low level callwheel initialization 10782127Sdillon * 10882127Sdillon * This code is called very early in the kernel initialization sequence, 10982127Sdillon * and may be called more then once. 11082127Sdillon */ 11182127Sdilloncaddr_t 11282127Sdillonkern_timeout_callwheel_alloc(caddr_t v) 11382127Sdillon{ 11482127Sdillon /* 11582127Sdillon * Calculate callout wheel size 11682127Sdillon */ 11782127Sdillon for (callwheelsize = 1, callwheelbits = 0; 11882127Sdillon callwheelsize < ncallout; 11982127Sdillon callwheelsize <<= 1, ++callwheelbits) 12082127Sdillon ; 12182127Sdillon callwheelmask = callwheelsize - 1; 12282127Sdillon 12382127Sdillon callout = (struct callout *)v; 12482127Sdillon v = (caddr_t)(callout + ncallout); 12582127Sdillon callwheel = (struct callout_tailq *)v; 12682127Sdillon v = (caddr_t)(callwheel + callwheelsize); 12782127Sdillon return(v); 12882127Sdillon} 12982127Sdillon 13082127Sdillon/* 13182127Sdillon * kern_timeout_callwheel_init() - initialize previously reserved callwheel 13282127Sdillon * space. 13382127Sdillon * 13482127Sdillon * This code is called just once, after the space reserved for the 13582127Sdillon * callout wheel has been finalized. 13682127Sdillon */ 13782127Sdillonvoid 13882127Sdillonkern_timeout_callwheel_init(void) 13982127Sdillon{ 14082127Sdillon int i; 14182127Sdillon 14282127Sdillon SLIST_INIT(&callfree); 14382127Sdillon for (i = 0; i < ncallout; i++) { 14482127Sdillon callout_init(&callout[i], 0); 14582127Sdillon callout[i].c_flags = CALLOUT_LOCAL_ALLOC; 14682127Sdillon SLIST_INSERT_HEAD(&callfree, &callout[i], c_links.sle); 14782127Sdillon } 14882127Sdillon for (i = 0; i < callwheelsize; i++) { 14982127Sdillon TAILQ_INIT(&callwheel[i]); 15082127Sdillon } 15193818Sjhb mtx_init(&callout_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 152122585Smckusick#ifdef DIAGNOSTIC 153122761Sphk mtx_init(&dont_sleep_in_callout, "dont_sleep_in_callout", NULL, MTX_DEF); 154122585Smckusick#endif 155127969Scperciva mtx_init(&callout_wait_lock, "callout_wait_lock", NULL, MTX_DEF); 156127969Scperciva cv_init(&callout_wait, "callout_wait"); 15782127Sdillon} 15882127Sdillon 15982127Sdillon/* 16029680Sgibbs * The callout mechanism is based on the work of Adam M. Costello and 16129680Sgibbs * George Varghese, published in a technical report entitled "Redesigning 16229680Sgibbs * the BSD Callout and Timer Facilities" and modified slightly for inclusion 16329680Sgibbs * in FreeBSD by Justin T. Gibbs. The original work on the data structures 164128630Shmp * used in this implementation was published by G. Varghese and T. Lauck in 16529680Sgibbs * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 16629680Sgibbs * the Efficient Implementation of a Timer Facility" in the Proceedings of 16729680Sgibbs * the 11th ACM Annual Symposium on Operating Systems Principles, 16829680Sgibbs * Austin, Texas Nov 1987. 16929680Sgibbs */ 17032388Sphk 17129680Sgibbs/* 1721541Srgrimes * Software (low priority) clock interrupt. 1731541Srgrimes * Run periodic events from timeout queue. 1741541Srgrimes */ 1751541Srgrimesvoid 17667551Sjhbsoftclock(void *dummy) 1771541Srgrimes{ 178102936Sphk struct callout *c; 179102936Sphk struct callout_tailq *bucket; 180102936Sphk int curticks; 181102936Sphk int steps; /* #steps since we last allowed interrupts */ 182115810Sphk int depth; 183115810Sphk int mpcalls; 184115810Sphk int gcalls; 185127969Scperciva int wakeup_cookie; 186122585Smckusick#ifdef DIAGNOSTIC 187122585Smckusick struct bintime bt1, bt2; 188122585Smckusick struct timespec ts2; 189122585Smckusick static uint64_t maxdt = 36893488147419102LL; /* 2 msec */ 190123254Sphk static timeout_t *lastfunc; 191122585Smckusick#endif 1921541Srgrimes 19333392Sphk#ifndef MAX_SOFTCLOCK_STEPS 19433392Sphk#define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */ 19533392Sphk#endif /* MAX_SOFTCLOCK_STEPS */ 19629680Sgibbs 197115810Sphk mpcalls = 0; 198115810Sphk gcalls = 0; 199115810Sphk depth = 0; 20029680Sgibbs steps = 0; 20172200Sbmilekic mtx_lock_spin(&callout_lock); 20229680Sgibbs while (softticks != ticks) { 20329805Sgibbs softticks++; 20429805Sgibbs /* 20529805Sgibbs * softticks may be modified by hard clock, so cache 20629805Sgibbs * it while we work on a given bucket. 20729805Sgibbs */ 20829805Sgibbs curticks = softticks; 20929805Sgibbs bucket = &callwheel[curticks & callwheelmask]; 21029805Sgibbs c = TAILQ_FIRST(bucket); 21129680Sgibbs while (c) { 212115810Sphk depth++; 21329805Sgibbs if (c->c_time != curticks) { 21429680Sgibbs c = TAILQ_NEXT(c, c_links.tqe); 21529680Sgibbs ++steps; 21629680Sgibbs if (steps >= MAX_SOFTCLOCK_STEPS) { 21729680Sgibbs nextsoftcheck = c; 21829805Sgibbs /* Give interrupts a chance. */ 21972200Sbmilekic mtx_unlock_spin(&callout_lock); 22081370Sjhb ; /* nothing */ 22172200Sbmilekic mtx_lock_spin(&callout_lock); 22229680Sgibbs c = nextsoftcheck; 22329680Sgibbs steps = 0; 22429680Sgibbs } 22529680Sgibbs } else { 22629680Sgibbs void (*c_func)(void *); 22729680Sgibbs void *c_arg; 22868889Sjake int c_flags; 22929680Sgibbs 23029680Sgibbs nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 23129805Sgibbs TAILQ_REMOVE(bucket, c, c_links.tqe); 23229680Sgibbs c_func = c->c_func; 23329680Sgibbs c_arg = c->c_arg; 23468889Sjake c_flags = c->c_flags; 23529680Sgibbs c->c_func = NULL; 23644510Swollman if (c->c_flags & CALLOUT_LOCAL_ALLOC) { 23744510Swollman c->c_flags = CALLOUT_LOCAL_ALLOC; 23844510Swollman SLIST_INSERT_HEAD(&callfree, c, 23944510Swollman c_links.sle); 24044510Swollman } else { 24144510Swollman c->c_flags = 24250673Sjlemon (c->c_flags & ~CALLOUT_PENDING); 24344510Swollman } 244127969Scperciva curr_callout = c; 24572200Sbmilekic mtx_unlock_spin(&callout_lock); 246115810Sphk if (!(c_flags & CALLOUT_MPSAFE)) { 24772200Sbmilekic mtx_lock(&Giant); 248115810Sphk gcalls++; 249133229Srwatson CTR1(KTR_CALLOUT, "callout %p", c_func); 250115810Sphk } else { 251115810Sphk mpcalls++; 252133229Srwatson CTR1(KTR_CALLOUT, "callout mpsafe %p", 253133229Srwatson c_func); 254115810Sphk } 255122585Smckusick#ifdef DIAGNOSTIC 256122585Smckusick binuptime(&bt1); 257122761Sphk mtx_lock(&dont_sleep_in_callout); 258122585Smckusick#endif 25929680Sgibbs c_func(c_arg); 260122585Smckusick#ifdef DIAGNOSTIC 261122761Sphk mtx_unlock(&dont_sleep_in_callout); 262122585Smckusick binuptime(&bt2); 263122585Smckusick bintime_sub(&bt2, &bt1); 264122585Smckusick if (bt2.frac > maxdt) { 265123254Sphk if (lastfunc != c_func || 266123254Sphk bt2.frac > maxdt * 2) { 267123254Sphk bintime2timespec(&bt2, &ts2); 268123254Sphk printf( 269123254Sphk "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 270123254Sphk c_func, c_arg, 271123254Sphk (intmax_t)ts2.tv_sec, 272123254Sphk ts2.tv_nsec); 273123254Sphk } 274122585Smckusick maxdt = bt2.frac; 275123254Sphk lastfunc = c_func; 276122585Smckusick } 277122585Smckusick#endif 27868889Sjake if (!(c_flags & CALLOUT_MPSAFE)) 27972200Sbmilekic mtx_unlock(&Giant); 28072200Sbmilekic mtx_lock_spin(&callout_lock); 281127969Scperciva curr_callout = NULL; 282127969Scperciva if (wakeup_needed) { 283127969Scperciva /* 284127969Scperciva * There might be someone waiting 285127969Scperciva * for the callout to complete. 286127969Scperciva */ 287127969Scperciva wakeup_cookie = wakeup_ctr; 288127969Scperciva mtx_unlock_spin(&callout_lock); 289127969Scperciva mtx_lock(&callout_wait_lock); 290127969Scperciva cv_broadcast(&callout_wait); 291127969Scperciva wakeup_done_ctr = wakeup_cookie; 292127969Scperciva mtx_unlock(&callout_wait_lock); 293127969Scperciva mtx_lock_spin(&callout_lock); 294127969Scperciva wakeup_needed = 0; 295128024Scperciva } 29629680Sgibbs steps = 0; 29729680Sgibbs c = nextsoftcheck; 29829680Sgibbs } 29929680Sgibbs } 3001541Srgrimes } 301115810Sphk avg_depth += (depth * 1000 - avg_depth) >> 8; 302115810Sphk avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 303115810Sphk avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 30429680Sgibbs nextsoftcheck = NULL; 30572200Sbmilekic mtx_unlock_spin(&callout_lock); 3061541Srgrimes} 3071541Srgrimes 3081541Srgrimes/* 3091541Srgrimes * timeout -- 3101541Srgrimes * Execute a function after a specified length of time. 3111541Srgrimes * 3121541Srgrimes * untimeout -- 3131541Srgrimes * Cancel previous timeout function call. 3141541Srgrimes * 31529680Sgibbs * callout_handle_init -- 31629680Sgibbs * Initialize a handle so that using it with untimeout is benign. 31729680Sgibbs * 3181541Srgrimes * See AT&T BCI Driver Reference Manual for specification. This 31929680Sgibbs * implementation differs from that one in that although an 32029680Sgibbs * identification value is returned from timeout, the original 32129680Sgibbs * arguments to timeout as well as the identifier are used to 32229680Sgibbs * identify entries for untimeout. 3231541Srgrimes */ 32429680Sgibbsstruct callout_handle 32529680Sgibbstimeout(ftn, arg, to_ticks) 32633824Sbde timeout_t *ftn; 3271541Srgrimes void *arg; 32869147Sjlemon int to_ticks; 3291541Srgrimes{ 33029680Sgibbs struct callout *new; 33129680Sgibbs struct callout_handle handle; 3321541Srgrimes 33372200Sbmilekic mtx_lock_spin(&callout_lock); 3341541Srgrimes 3351541Srgrimes /* Fill in the next free callout structure. */ 33629680Sgibbs new = SLIST_FIRST(&callfree); 33729680Sgibbs if (new == NULL) 33829680Sgibbs /* XXX Attempt to malloc first */ 3391541Srgrimes panic("timeout table full"); 34029680Sgibbs SLIST_REMOVE_HEAD(&callfree, c_links.sle); 34144510Swollman 34244510Swollman callout_reset(new, to_ticks, ftn, arg); 3431541Srgrimes 34444510Swollman handle.callout = new; 34572200Sbmilekic mtx_unlock_spin(&callout_lock); 34629680Sgibbs return (handle); 3471541Srgrimes} 3481541Srgrimes 3491541Srgrimesvoid 35029680Sgibbsuntimeout(ftn, arg, handle) 35133824Sbde timeout_t *ftn; 3521541Srgrimes void *arg; 35329680Sgibbs struct callout_handle handle; 3541541Srgrimes{ 3551541Srgrimes 35629680Sgibbs /* 35729680Sgibbs * Check for a handle that was initialized 35829680Sgibbs * by callout_handle_init, but never used 35929680Sgibbs * for a real timeout. 36029680Sgibbs */ 36129680Sgibbs if (handle.callout == NULL) 36229680Sgibbs return; 36329680Sgibbs 36472200Sbmilekic mtx_lock_spin(&callout_lock); 36544510Swollman if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 36644510Swollman callout_stop(handle.callout); 36772200Sbmilekic mtx_unlock_spin(&callout_lock); 3681541Srgrimes} 3691541Srgrimes 37024101Sbdevoid 37129680Sgibbscallout_handle_init(struct callout_handle *handle) 37229680Sgibbs{ 37329680Sgibbs handle->callout = NULL; 37429680Sgibbs} 37529680Sgibbs 37644510Swollman/* 37744510Swollman * New interface; clients allocate their own callout structures. 37844510Swollman * 37944510Swollman * callout_reset() - establish or change a timeout 38044510Swollman * callout_stop() - disestablish a timeout 38144510Swollman * callout_init() - initialize a callout structure so that it can 38244510Swollman * safely be passed to callout_reset() and callout_stop() 38344510Swollman * 38450673Sjlemon * <sys/callout.h> defines three convenience macros: 38544510Swollman * 38650673Sjlemon * callout_active() - returns truth if callout has not been serviced 38750673Sjlemon * callout_pending() - returns truth if callout is still waiting for timeout 38850673Sjlemon * callout_deactivate() - marks the callout as having been serviced 38944510Swollman */ 39044510Swollmanvoid 39169147Sjlemoncallout_reset(c, to_ticks, ftn, arg) 39244510Swollman struct callout *c; 39344510Swollman int to_ticks; 39492723Salfred void (*ftn)(void *); 39544510Swollman void *arg; 39644510Swollman{ 39744510Swollman 39872200Sbmilekic mtx_lock_spin(&callout_lock); 399127969Scperciva if (c == curr_callout && wakeup_needed) { 400127969Scperciva /* 401127969Scperciva * We're being asked to reschedule a callout which is 402127969Scperciva * currently in progress, and someone has called 403127969Scperciva * callout_drain to kill that callout. Don't reschedule. 404127969Scperciva */ 405127969Scperciva mtx_unlock_spin(&callout_lock); 406127969Scperciva return; 407128024Scperciva } 408133190Scperciva if (c->c_flags & CALLOUT_PENDING) { 409133190Scperciva if (nextsoftcheck == c) { 410133190Scperciva nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 411133190Scperciva } 412133190Scperciva TAILQ_REMOVE(&callwheel[c->c_time & callwheelmask], c, 413133190Scperciva c_links.tqe); 41444510Swollman 415133190Scperciva /* 416133190Scperciva * Part of the normal "stop a pending callout" process 417133190Scperciva * is to clear the CALLOUT_ACTIVE and CALLOUT_PENDING 418133190Scperciva * flags. We're not going to bother doing that here, 419133190Scperciva * because we're going to be setting those flags ten lines 420133190Scperciva * after this point, and we're holding callout_lock 421133190Scperciva * between now and then. 422133190Scperciva */ 423133190Scperciva } 424133190Scperciva 42544510Swollman /* 42681370Sjhb * We could unlock callout_lock here and lock it again before the 42781370Sjhb * TAILQ_INSERT_TAIL, but there's no point since doing this setup 42881370Sjhb * doesn't take much time. 42944510Swollman */ 43044510Swollman if (to_ticks <= 0) 43144510Swollman to_ticks = 1; 43244510Swollman 43344510Swollman c->c_arg = arg; 43469147Sjlemon c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING); 43544510Swollman c->c_func = ftn; 43644510Swollman c->c_time = ticks + to_ticks; 43744510Swollman TAILQ_INSERT_TAIL(&callwheel[c->c_time & callwheelmask], 43844510Swollman c, c_links.tqe); 43972200Sbmilekic mtx_unlock_spin(&callout_lock); 44044510Swollman} 44144510Swollman 44281481Sjhbint 443127969Scperciva_callout_stop_safe(c, safe) 444127969Scperciva struct callout *c; 445127969Scperciva int safe; 446127969Scperciva{ 447127969Scperciva int wakeup_cookie; 448127969Scperciva 44972200Sbmilekic mtx_lock_spin(&callout_lock); 45044510Swollman /* 45144510Swollman * Don't attempt to delete a callout that's not on the queue. 45244510Swollman */ 45344510Swollman if (!(c->c_flags & CALLOUT_PENDING)) { 45450673Sjlemon c->c_flags &= ~CALLOUT_ACTIVE; 455127969Scperciva if (c == curr_callout && safe) { 456128024Scperciva /* We need to wait until the callout is finished. */ 457127969Scperciva wakeup_needed = 1; 458127969Scperciva wakeup_cookie = wakeup_ctr++; 459127969Scperciva mtx_unlock_spin(&callout_lock); 460127969Scperciva mtx_lock(&callout_wait_lock); 461128024Scperciva 462127969Scperciva /* 463127969Scperciva * Check to make sure that softclock() didn't 464127969Scperciva * do the wakeup in between our dropping 465127969Scperciva * callout_lock and picking up callout_wait_lock 466127969Scperciva */ 467127969Scperciva if (wakeup_cookie - wakeup_done_ctr > 0) 468127969Scperciva cv_wait(&callout_wait, &callout_wait_lock); 469127969Scperciva 470127969Scperciva mtx_unlock(&callout_wait_lock); 471127969Scperciva } else 472127969Scperciva mtx_unlock_spin(&callout_lock); 47381481Sjhb return (0); 47444510Swollman } 47550673Sjlemon c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 47644510Swollman 47744510Swollman if (nextsoftcheck == c) { 47844510Swollman nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 47944510Swollman } 48044510Swollman TAILQ_REMOVE(&callwheel[c->c_time & callwheelmask], c, c_links.tqe); 48144510Swollman c->c_func = NULL; 48244510Swollman 48344510Swollman if (c->c_flags & CALLOUT_LOCAL_ALLOC) { 48444510Swollman SLIST_INSERT_HEAD(&callfree, c, c_links.sle); 48544510Swollman } 48672200Sbmilekic mtx_unlock_spin(&callout_lock); 48781481Sjhb return (1); 48844510Swollman} 48944510Swollman 49044510Swollmanvoid 49169147Sjlemoncallout_init(c, mpsafe) 49244510Swollman struct callout *c; 49369147Sjlemon int mpsafe; 49444510Swollman{ 49544527Swollman bzero(c, sizeof *c); 49669147Sjlemon if (mpsafe) 49769147Sjlemon c->c_flags |= CALLOUT_MPSAFE; 49844510Swollman} 49944510Swollman 50031950Snate#ifdef APM_FIXUP_CALLTODO 50131950Snate/* 50231950Snate * Adjust the kernel calltodo timeout list. This routine is used after 50331950Snate * an APM resume to recalculate the calltodo timer list values with the 50431950Snate * number of hz's we have been sleeping. The next hardclock() will detect 50531950Snate * that there are fired timers and run softclock() to execute them. 50631950Snate * 50731950Snate * Please note, I have not done an exhaustive analysis of what code this 50831950Snate * might break. I am motivated to have my select()'s and alarm()'s that 50931950Snate * have expired during suspend firing upon resume so that the applications 51031950Snate * which set the timer can do the maintanence the timer was for as close 51131950Snate * as possible to the originally intended time. Testing this code for a 51231950Snate * week showed that resuming from a suspend resulted in 22 to 25 timers 51331950Snate * firing, which seemed independant on whether the suspend was 2 hours or 51431950Snate * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 51531950Snate */ 51631950Snatevoid 51731950Snateadjust_timeout_calltodo(time_change) 51831950Snate struct timeval *time_change; 51931950Snate{ 52031950Snate register struct callout *p; 52131950Snate unsigned long delta_ticks; 52231950Snate 52331950Snate /* 52431950Snate * How many ticks were we asleep? 52536127Sbde * (stolen from tvtohz()). 52631950Snate */ 52731950Snate 52831950Snate /* Don't do anything */ 52931950Snate if (time_change->tv_sec < 0) 53031950Snate return; 53131950Snate else if (time_change->tv_sec <= LONG_MAX / 1000000) 53231950Snate delta_ticks = (time_change->tv_sec * 1000000 + 53331950Snate time_change->tv_usec + (tick - 1)) / tick + 1; 53431950Snate else if (time_change->tv_sec <= LONG_MAX / hz) 53531950Snate delta_ticks = time_change->tv_sec * hz + 53631950Snate (time_change->tv_usec + (tick - 1)) / tick + 1; 53731950Snate else 53831950Snate delta_ticks = LONG_MAX; 53931950Snate 54031950Snate if (delta_ticks > INT_MAX) 54131950Snate delta_ticks = INT_MAX; 54231950Snate 54331950Snate /* 54431950Snate * Now rip through the timer calltodo list looking for timers 54531950Snate * to expire. 54631950Snate */ 54731950Snate 54831950Snate /* don't collide with softclock() */ 54972200Sbmilekic mtx_lock_spin(&callout_lock); 55031950Snate for (p = calltodo.c_next; p != NULL; p = p->c_next) { 55131950Snate p->c_time -= delta_ticks; 55231950Snate 55331950Snate /* Break if the timer had more time on it than delta_ticks */ 55431950Snate if (p->c_time > 0) 55531950Snate break; 55631950Snate 55731950Snate /* take back the ticks the timer didn't use (p->c_time <= 0) */ 55831950Snate delta_ticks = -p->c_time; 55931950Snate } 56072200Sbmilekic mtx_unlock_spin(&callout_lock); 56131950Snate 56231950Snate return; 56331950Snate} 56431950Snate#endif /* APM_FIXUP_CALLTODO */ 565