sys/kern/kern_systimer.c

   1 /*
   2  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sys/kern/kern_systimer.c,v 1.10 2007/04/30 07:18:54 dillon Exp $
  35  */
  36
  37 /*
  38  * WARNING!  THE SYSTIMER MODULE DOES NOT OPERATE OR DISPATCH WITH THE
  39  * MP LOCK HELD.  ALL CODE USING THIS MODULE MUST BE MP-SAFE.
  40  *
  41  * This code implements a fine-grained per-cpu system timer which is
  42  * ultimately based on a hardware timer.  The hardware timer abstraction
  43  * is sufficiently disconnected from this code to support both per-cpu
  44  * hardware timers or a single system-wide hardware timer.
  45  *
  46  * WARNING!  During early boot if a new system timer is selected, existing
  47  * timeouts will not be effected and will thus occur slower or faster.
  48  * periodic timers will be adjusted at the next periodic load.
  49  *
  50  * Notes on machine-dependant code (in arch/arch/systimer.c)
  51  *
  52  * cputimer_intr_reload()       Reload the one-shot (per-cpu basis)
  53  */
  54
  55 #include <sys/param.h>
  56 #include <sys/kernel.h>
  57 #include <sys/systm.h>
  58 #include <sys/thread.h>
  59 #include <sys/globaldata.h>
  60 #include <sys/systimer.h>
  61 #include <sys/thread2.h>
  62
  63 /*
  64  * Execute ready systimers.  Called directly from the platform-specific
  65  * one-shot timer clock interrupt (e.g. clkintr()) or via an IPI.  May
  66  * be called simultaniously on multiple cpus and always operations on
  67  * the current cpu's queue.  Systimer functions are responsible for calling
  68  * hardclock, statclock, and other finely-timed routines.
  69  */
  70 void
  71 systimer_intr(sysclock_t *timep, int dummy, struct intrframe *frame)
  72 {
  73     globaldata_t gd = mycpu;
  74     sysclock_t time = *timep;
  75     systimer_t info;
  76
  77     if (gd->gd_syst_nest)
  78         return;
  79
  80     crit_enter();
  81     ++gd->gd_syst_nest;
  82     while ((info = TAILQ_FIRST(&gd->gd_systimerq)) != NULL) {
  83         /*
  84          * If we haven't reached the requested time, tell the cputimer
  85          * how much is left and break out.
  86          */
  87         if ((int)(info->time - time) > 0) {
  88             cputimer_intr_reload(info->time - time);
  89             break;
  90         }
  91
  92         /*
  93          * Dequeue and execute
  94          */
  95         info->flags &= ~SYSTF_ONQUEUE;
  96         TAILQ_REMOVE(info->queue, info, node);
  97         crit_exit();
  98         info->func(info, frame);
  99         crit_enter();
 100
 101         /*
 102          * Reinstall if periodic.  If this is a non-queued periodic
 103          * interrupt do not allow multiple events to build up (used
 104          * for things like the callout timer to prevent premature timeouts
 105          * due to long interrupt disablements, BIOS 8254 glitching, and so
 106          * forth).  However, we still want to keep things synchronized between
 107          * cpus for efficient handling of the timer interrupt so jump in
 108          * multiples of the periodic rate.
 109          */
 110         if (info->periodic) {
 111             if (info->which != sys_cputimer) {
 112                 info->periodic = sys_cputimer->fromhz(info->freq);
 113                 info->which = sys_cputimer;
 114             }
 115             info->time += info->periodic;
 116             if ((info->flags & SYSTF_NONQUEUED) &&
 117                 (int)(info->time - time) <= 0
 118             ) {
 119                 info->time += ((time - info->time + info->periodic - 1) /
 120                                 info->periodic) * info->periodic;
 121             }
 122             systimer_add(info);
 123         }
 124     }
 125     --gd->gd_syst_nest;
 126     crit_exit();
 127 }
 128
 129 void
 130 systimer_add(systimer_t info)
 131 {
 132     struct globaldata *gd = mycpu;
 133
 134     KKASSERT((info->flags & (SYSTF_ONQUEUE|SYSTF_IPIRUNNING)) == 0);
 135     crit_enter();
 136     if (info->gd == gd) {
 137         systimer_t scan1;
 138         systimer_t scan2;
 139         scan1 = TAILQ_FIRST(&gd->gd_systimerq);
 140         if (scan1 == NULL || (int)(scan1->time - info->time) > 0) {
 141             cputimer_intr_reload(info->time - sys_cputimer->count());
 142             TAILQ_INSERT_HEAD(&gd->gd_systimerq, info, node);
 143         } else {
 144             scan2 = TAILQ_LAST(&gd->gd_systimerq, systimerq);
 145             for (;;) {
 146                 if (scan1 == NULL) {
 147                     TAILQ_INSERT_TAIL(&gd->gd_systimerq, info, node);
 148                     break;
 149                 }
 150                 if ((int)(scan1->time - info->time) > 0) {
 151                     TAILQ_INSERT_BEFORE(scan1, info, node);
 152                     break;
 153                 }
 154                 if ((int)(scan2->time - info->time) <= 0) {
 155                     TAILQ_INSERT_AFTER(&gd->gd_systimerq, scan2, info, node);
 156                     break;
 157                 }
 158                 scan1 = TAILQ_NEXT(scan1, node);
 159                 scan2 = TAILQ_PREV(scan2, systimerq, node);
 160             }
 161         }
 162         info->flags = (info->flags | SYSTF_ONQUEUE) & ~SYSTF_IPIRUNNING;
 163         info->queue = &gd->gd_systimerq;
 164     } else {
 165 #ifdef SMP
 166         info->flags |= SYSTF_IPIRUNNING;
 167         lwkt_send_ipiq(info->gd, (ipifunc1_t)systimer_add, info);
 168 #else
 169         panic("systimer_add: bad gd in info %p", info);
 170 #endif
 171     }
 172     crit_exit();
 173 }
 174
 175 /*
 176  * systimer_del()
 177  *
 178  *      Delete a system timer.  Only the owning cpu can delete a timer.
 179  */
 180 void
 181 systimer_del(systimer_t info)
 182 {
 183     KKASSERT(info->gd == mycpu && (info->flags & SYSTF_IPIRUNNING) == 0);
 184     crit_enter();
 185     if (info->flags & SYSTF_ONQUEUE) {
 186         TAILQ_REMOVE(info->queue, info, node);
 187         info->flags &= ~SYSTF_ONQUEUE;
 188     }
 189     crit_exit();
 190 }
 191
 192 /*
 193  * systimer_init_periodic()
 194  *
 195  *      Initialize a periodic timer at the specified frequency and add
 196  *      it to the system.  The frequency is uncompensated and approximate.
 197  *
 198  *      Try to synchronize multi registrations of the same or similar
 199  *      frequencies so the hardware interrupt is able to dispatch several
 200  *      at together by adjusting the phase of the initial interrupt.  This
 201  *      helps SMP.  Note that we are not attempting to synchronize to
 202  *      the realtime clock.
 203  */
 204 void
 205 systimer_init_periodic(systimer_t info, void *func, void *data, int hz)
 206 {
 207     sysclock_t base_count;
 208
 209     bzero(info, sizeof(struct systimer));
 210     info->periodic = sys_cputimer->fromhz(hz);
 211     base_count = sys_cputimer->count();
 212     base_count = base_count - (base_count % info->periodic);
 213     info->time = base_count + info->periodic;
 214     info->func = func;
 215     info->data = data;
 216     info->freq = hz;
 217     info->which = sys_cputimer;
 218     info->gd = mycpu;
 219     systimer_add(info);
 220 }
 221
 222 void
 223 systimer_init_periodic_nq(systimer_t info, void *func, void *data, int hz)
 224 {
 225     sysclock_t base_count;
 226
 227     bzero(info, sizeof(struct systimer));
 228     info->periodic = sys_cputimer->fromhz(hz);
 229     base_count = sys_cputimer->count();
 230     base_count = base_count - (base_count % info->periodic);
 231     info->time = base_count + info->periodic;
 232     info->func = func;
 233     info->data = data;
 234     info->freq = hz;
 235     info->which = sys_cputimer;
 236     info->gd = mycpu;
 237     info->flags |= SYSTF_NONQUEUED;
 238     systimer_add(info);
 239 }
 240
 241 /*
 242  * Adjust the periodic interval for a periodic timer which is already
 243  * running.  The current timeout is not effected.
 244  */
 245 void
 246 systimer_adjust_periodic(systimer_t info, int hz)
 247 {
 248     crit_enter();
 249     info->periodic = sys_cputimer->fromhz(hz);
 250     info->freq = hz;
 251     info->which = sys_cputimer;
 252     crit_exit();
 253 }
 254
 255 /*
 256  * systimer_init_oneshot()
 257  *
 258  *      Initialize a periodic timer at the specified frequency and add
 259  *      it to the system.  The frequency is uncompensated and approximate.
 260  */
 261 void
 262 systimer_init_oneshot(systimer_t info, void *func, void *data, int us)
 263 {
 264     bzero(info, sizeof(struct systimer));
 265     info->time = sys_cputimer->count() + sys_cputimer->fromus(us);
 266     info->func = func;
 267     info->data = data;
 268     info->which = sys_cputimer;
 269     info->gd = mycpu;
 270     systimer_add(info);
 271 }
 272