kern_timeout.c revision 69147
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 * 3. All advertising materials mentioning features or use of this software 191541Srgrimes * must display the following acknowledgement: 201541Srgrimes * This product includes software developed by the University of 211541Srgrimes * California, Berkeley and its contributors. 221541Srgrimes * 4. Neither the name of the University nor the names of its contributors 231541Srgrimes * may be used to endorse or promote products derived from this software 241541Srgrimes * without specific prior written permission. 251541Srgrimes * 261541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 271541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 281541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 291541Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 301541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 311541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 321541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 331541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 341541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 351541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 361541Srgrimes * SUCH DAMAGE. 371541Srgrimes * 3844510Swollman * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 3950477Speter * $FreeBSD: head/sys/kern/kern_timeout.c 69147 2000-11-25 06:22:16Z jlemon $ 401541Srgrimes */ 411541Srgrimes 421541Srgrimes#include <sys/param.h> 431541Srgrimes#include <sys/systm.h> 4433392Sphk#include <sys/callout.h> 451541Srgrimes#include <sys/kernel.h> 4668840Sjhb#include <sys/mutex.h> 471541Srgrimes 4833392Sphk/* 4933392Sphk * TODO: 5033392Sphk * allocate more timeout table slots when table overflows. 5133392Sphk */ 5233392Sphk 5333392Sphk/* Exported to machdep.c and/or kern_clock.c. */ 5429680Sgibbsstruct callout *callout; 5529680Sgibbsstruct callout_list callfree; 5629680Sgibbsint callwheelsize, callwheelbits, callwheelmask; 5729680Sgibbsstruct callout_tailq *callwheel; 5833392Sphkint softticks; /* Like ticks, but for softclock(). */ 5968889Sjakestruct mtx callout_lock; 602112Swollman 6129680Sgibbsstatic struct callout *nextsoftcheck; /* Next callout to be checked. */ 621541Srgrimes 631541Srgrimes/* 6429680Sgibbs * The callout mechanism is based on the work of Adam M. Costello and 6529680Sgibbs * George Varghese, published in a technical report entitled "Redesigning 6629680Sgibbs * the BSD Callout and Timer Facilities" and modified slightly for inclusion 6729680Sgibbs * in FreeBSD by Justin T. Gibbs. The original work on the data structures 6829680Sgibbs * used in this implementation was published by G.Varghese and A. Lauck in 6929680Sgibbs * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 7029680Sgibbs * the Efficient Implementation of a Timer Facility" in the Proceedings of 7129680Sgibbs * the 11th ACM Annual Symposium on Operating Systems Principles, 7229680Sgibbs * Austin, Texas Nov 1987. 7329680Sgibbs */ 7432388Sphk 7529680Sgibbs/* 761541Srgrimes * Software (low priority) clock interrupt. 771541Srgrimes * Run periodic events from timeout queue. 781541Srgrimes */ 791541Srgrimesvoid 8067551Sjhbsoftclock(void *dummy) 811541Srgrimes{ 821541Srgrimes register struct callout *c; 8329805Sgibbs register struct callout_tailq *bucket; 841541Srgrimes register int s; 8529805Sgibbs register int curticks; 8633392Sphk register int steps; /* #steps since we last allowed interrupts */ 871541Srgrimes 8833392Sphk#ifndef MAX_SOFTCLOCK_STEPS 8933392Sphk#define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */ 9033392Sphk#endif /* MAX_SOFTCLOCK_STEPS */ 9129680Sgibbs 9229680Sgibbs steps = 0; 931541Srgrimes s = splhigh(); 9468889Sjake mtx_enter(&callout_lock, MTX_SPIN); 9529680Sgibbs while (softticks != ticks) { 9629805Sgibbs softticks++; 9729805Sgibbs /* 9829805Sgibbs * softticks may be modified by hard clock, so cache 9929805Sgibbs * it while we work on a given bucket. 10029805Sgibbs */ 10129805Sgibbs curticks = softticks; 10229805Sgibbs bucket = &callwheel[curticks & callwheelmask]; 10329805Sgibbs c = TAILQ_FIRST(bucket); 10429680Sgibbs while (c) { 10529805Sgibbs if (c->c_time != curticks) { 10629680Sgibbs c = TAILQ_NEXT(c, c_links.tqe); 10729680Sgibbs ++steps; 10829680Sgibbs if (steps >= MAX_SOFTCLOCK_STEPS) { 10929680Sgibbs nextsoftcheck = c; 11029805Sgibbs /* Give interrupts a chance. */ 11168889Sjake mtx_exit(&callout_lock, MTX_SPIN); 11229680Sgibbs splx(s); 11329680Sgibbs s = splhigh(); 11468889Sjake mtx_enter(&callout_lock, MTX_SPIN); 11529680Sgibbs c = nextsoftcheck; 11629680Sgibbs steps = 0; 11729680Sgibbs } 11829680Sgibbs } else { 11929680Sgibbs void (*c_func)(void *); 12029680Sgibbs void *c_arg; 12168889Sjake int c_flags; 12229680Sgibbs 12329680Sgibbs nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 12429805Sgibbs TAILQ_REMOVE(bucket, c, c_links.tqe); 12529680Sgibbs c_func = c->c_func; 12629680Sgibbs c_arg = c->c_arg; 12768889Sjake c_flags = c->c_flags; 12829680Sgibbs c->c_func = NULL; 12944510Swollman if (c->c_flags & CALLOUT_LOCAL_ALLOC) { 13044510Swollman c->c_flags = CALLOUT_LOCAL_ALLOC; 13144510Swollman SLIST_INSERT_HEAD(&callfree, c, 13244510Swollman c_links.sle); 13344510Swollman } else { 13444510Swollman c->c_flags = 13550673Sjlemon (c->c_flags & ~CALLOUT_PENDING); 13644510Swollman } 13768889Sjake mtx_exit(&callout_lock, MTX_SPIN); 13868889Sjake if (!(c_flags & CALLOUT_MPSAFE)) 13968889Sjake mtx_enter(&Giant, MTX_DEF); 14029680Sgibbs splx(s); 14129680Sgibbs c_func(c_arg); 14229680Sgibbs s = splhigh(); 14368889Sjake if (!(c_flags & CALLOUT_MPSAFE)) 14468889Sjake mtx_exit(&Giant, MTX_DEF); 14568889Sjake mtx_enter(&callout_lock, MTX_SPIN); 14629680Sgibbs steps = 0; 14729680Sgibbs c = nextsoftcheck; 14829680Sgibbs } 14929680Sgibbs } 1501541Srgrimes } 15129680Sgibbs nextsoftcheck = NULL; 15268889Sjake mtx_exit(&callout_lock, MTX_SPIN); 1531541Srgrimes splx(s); 1541541Srgrimes} 1551541Srgrimes 1561541Srgrimes/* 1571541Srgrimes * timeout -- 1581541Srgrimes * Execute a function after a specified length of time. 1591541Srgrimes * 1601541Srgrimes * untimeout -- 1611541Srgrimes * Cancel previous timeout function call. 1621541Srgrimes * 16329680Sgibbs * callout_handle_init -- 16429680Sgibbs * Initialize a handle so that using it with untimeout is benign. 16529680Sgibbs * 1661541Srgrimes * See AT&T BCI Driver Reference Manual for specification. This 16729680Sgibbs * implementation differs from that one in that although an 16829680Sgibbs * identification value is returned from timeout, the original 16929680Sgibbs * arguments to timeout as well as the identifier are used to 17029680Sgibbs * identify entries for untimeout. 1711541Srgrimes */ 17229680Sgibbsstruct callout_handle 17329680Sgibbstimeout(ftn, arg, to_ticks) 17433824Sbde timeout_t *ftn; 1751541Srgrimes void *arg; 17669147Sjlemon int to_ticks; 1771541Srgrimes{ 17829680Sgibbs int s; 17929680Sgibbs struct callout *new; 18029680Sgibbs struct callout_handle handle; 1811541Srgrimes 1821541Srgrimes s = splhigh(); 18368889Sjake mtx_enter(&callout_lock, MTX_SPIN); 1841541Srgrimes 1851541Srgrimes /* Fill in the next free callout structure. */ 18629680Sgibbs new = SLIST_FIRST(&callfree); 18729680Sgibbs if (new == NULL) 18829680Sgibbs /* XXX Attempt to malloc first */ 1891541Srgrimes panic("timeout table full"); 19029680Sgibbs SLIST_REMOVE_HEAD(&callfree, c_links.sle); 19144510Swollman 19244510Swollman callout_reset(new, to_ticks, ftn, arg); 1931541Srgrimes 19444510Swollman handle.callout = new; 19568889Sjake mtx_exit(&callout_lock, MTX_SPIN); 1961541Srgrimes splx(s); 19729680Sgibbs return (handle); 1981541Srgrimes} 1991541Srgrimes 2001541Srgrimesvoid 20129680Sgibbsuntimeout(ftn, arg, handle) 20233824Sbde timeout_t *ftn; 2031541Srgrimes void *arg; 20429680Sgibbs struct callout_handle handle; 2051541Srgrimes{ 2061541Srgrimes register int s; 2071541Srgrimes 20829680Sgibbs /* 20929680Sgibbs * Check for a handle that was initialized 21029680Sgibbs * by callout_handle_init, but never used 21129680Sgibbs * for a real timeout. 21229680Sgibbs */ 21329680Sgibbs if (handle.callout == NULL) 21429680Sgibbs return; 21529680Sgibbs 2161541Srgrimes s = splhigh(); 21768889Sjake mtx_enter(&callout_lock, MTX_SPIN); 21844510Swollman if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 21944510Swollman callout_stop(handle.callout); 22068889Sjake mtx_exit(&callout_lock, MTX_SPIN); 2211541Srgrimes splx(s); 2221541Srgrimes} 2231541Srgrimes 22424101Sbdevoid 22529680Sgibbscallout_handle_init(struct callout_handle *handle) 22629680Sgibbs{ 22729680Sgibbs handle->callout = NULL; 22829680Sgibbs} 22929680Sgibbs 23044510Swollman/* 23144510Swollman * New interface; clients allocate their own callout structures. 23244510Swollman * 23344510Swollman * callout_reset() - establish or change a timeout 23444510Swollman * callout_stop() - disestablish a timeout 23544510Swollman * callout_init() - initialize a callout structure so that it can 23644510Swollman * safely be passed to callout_reset() and callout_stop() 23744510Swollman * 23850673Sjlemon * <sys/callout.h> defines three convenience macros: 23944510Swollman * 24050673Sjlemon * callout_active() - returns truth if callout has not been serviced 24150673Sjlemon * callout_pending() - returns truth if callout is still waiting for timeout 24250673Sjlemon * callout_deactivate() - marks the callout as having been serviced 24344510Swollman */ 24444510Swollmanvoid 24569147Sjlemoncallout_reset(c, to_ticks, ftn, arg) 24644510Swollman struct callout *c; 24744510Swollman int to_ticks; 24844510Swollman void (*ftn) __P((void *)); 24944510Swollman void *arg; 25044510Swollman{ 25144510Swollman int s; 25244510Swollman 25344510Swollman s = splhigh(); 25468889Sjake mtx_enter(&callout_lock, MTX_SPIN); 25544510Swollman if (c->c_flags & CALLOUT_PENDING) 25644510Swollman callout_stop(c); 25744510Swollman 25844510Swollman /* 25944510Swollman * We could spl down here and back up at the TAILQ_INSERT_TAIL, 26044510Swollman * but there's no point since doing this setup doesn't take much 26150673Sjlemon * time. 26244510Swollman */ 26344510Swollman if (to_ticks <= 0) 26444510Swollman to_ticks = 1; 26544510Swollman 26644510Swollman c->c_arg = arg; 26769147Sjlemon c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING); 26844510Swollman c->c_func = ftn; 26944510Swollman c->c_time = ticks + to_ticks; 27044510Swollman TAILQ_INSERT_TAIL(&callwheel[c->c_time & callwheelmask], 27144510Swollman c, c_links.tqe); 27268889Sjake mtx_exit(&callout_lock, MTX_SPIN); 27344510Swollman splx(s); 27444510Swollman} 27544510Swollman 27644510Swollmanvoid 27744510Swollmancallout_stop(c) 27844510Swollman struct callout *c; 27944510Swollman{ 28044510Swollman int s; 28144510Swollman 28244510Swollman s = splhigh(); 28368889Sjake mtx_enter(&callout_lock, MTX_SPIN); 28444510Swollman /* 28544510Swollman * Don't attempt to delete a callout that's not on the queue. 28644510Swollman */ 28744510Swollman if (!(c->c_flags & CALLOUT_PENDING)) { 28850673Sjlemon c->c_flags &= ~CALLOUT_ACTIVE; 28968889Sjake mtx_exit(&callout_lock, MTX_SPIN); 29044510Swollman splx(s); 29144510Swollman return; 29244510Swollman } 29350673Sjlemon c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 29444510Swollman 29544510Swollman if (nextsoftcheck == c) { 29644510Swollman nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 29744510Swollman } 29844510Swollman TAILQ_REMOVE(&callwheel[c->c_time & callwheelmask], c, c_links.tqe); 29944510Swollman c->c_func = NULL; 30044510Swollman 30144510Swollman if (c->c_flags & CALLOUT_LOCAL_ALLOC) { 30244510Swollman SLIST_INSERT_HEAD(&callfree, c, c_links.sle); 30344510Swollman } 30468889Sjake mtx_exit(&callout_lock, MTX_SPIN); 30544510Swollman splx(s); 30644510Swollman} 30744510Swollman 30844510Swollmanvoid 30969147Sjlemoncallout_init(c, mpsafe) 31044510Swollman struct callout *c; 31169147Sjlemon int mpsafe; 31244510Swollman{ 31344527Swollman bzero(c, sizeof *c); 31469147Sjlemon if (mpsafe) 31569147Sjlemon c->c_flags |= CALLOUT_MPSAFE; 31644510Swollman} 31744510Swollman 31831950Snate#ifdef APM_FIXUP_CALLTODO 31931950Snate/* 32031950Snate * Adjust the kernel calltodo timeout list. This routine is used after 32131950Snate * an APM resume to recalculate the calltodo timer list values with the 32231950Snate * number of hz's we have been sleeping. The next hardclock() will detect 32331950Snate * that there are fired timers and run softclock() to execute them. 32431950Snate * 32531950Snate * Please note, I have not done an exhaustive analysis of what code this 32631950Snate * might break. I am motivated to have my select()'s and alarm()'s that 32731950Snate * have expired during suspend firing upon resume so that the applications 32831950Snate * which set the timer can do the maintanence the timer was for as close 32931950Snate * as possible to the originally intended time. Testing this code for a 33031950Snate * week showed that resuming from a suspend resulted in 22 to 25 timers 33131950Snate * firing, which seemed independant on whether the suspend was 2 hours or 33231950Snate * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 33331950Snate */ 33431950Snatevoid 33531950Snateadjust_timeout_calltodo(time_change) 33631950Snate struct timeval *time_change; 33731950Snate{ 33831950Snate register struct callout *p; 33931950Snate unsigned long delta_ticks; 34031950Snate int s; 34131950Snate 34231950Snate /* 34331950Snate * How many ticks were we asleep? 34436127Sbde * (stolen from tvtohz()). 34531950Snate */ 34631950Snate 34731950Snate /* Don't do anything */ 34831950Snate if (time_change->tv_sec < 0) 34931950Snate return; 35031950Snate else if (time_change->tv_sec <= LONG_MAX / 1000000) 35131950Snate delta_ticks = (time_change->tv_sec * 1000000 + 35231950Snate time_change->tv_usec + (tick - 1)) / tick + 1; 35331950Snate else if (time_change->tv_sec <= LONG_MAX / hz) 35431950Snate delta_ticks = time_change->tv_sec * hz + 35531950Snate (time_change->tv_usec + (tick - 1)) / tick + 1; 35631950Snate else 35731950Snate delta_ticks = LONG_MAX; 35831950Snate 35931950Snate if (delta_ticks > INT_MAX) 36031950Snate delta_ticks = INT_MAX; 36131950Snate 36231950Snate /* 36331950Snate * Now rip through the timer calltodo list looking for timers 36431950Snate * to expire. 36531950Snate */ 36631950Snate 36731950Snate /* don't collide with softclock() */ 36831950Snate s = splhigh(); 36968889Sjake mtx_enter(&callout_lock, MTX_SPIN); 37031950Snate for (p = calltodo.c_next; p != NULL; p = p->c_next) { 37131950Snate p->c_time -= delta_ticks; 37231950Snate 37331950Snate /* Break if the timer had more time on it than delta_ticks */ 37431950Snate if (p->c_time > 0) 37531950Snate break; 37631950Snate 37731950Snate /* take back the ticks the timer didn't use (p->c_time <= 0) */ 37831950Snate delta_ticks = -p->c_time; 37931950Snate } 38068889Sjake mtx_exit(&callout_lock, MTX_SPIN); 38131950Snate splx(s); 38231950Snate 38331950Snate return; 38431950Snate} 38531950Snate#endif /* APM_FIXUP_CALLTODO */ 386