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 1.8 2005/10/25 17:26:54 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  * Notes on machine-dependant code (in arch/arch/systimer.c)
  47  *
  48  * cputimer_intr_reload()       Reload the one-shot (per-cpu basis)
  49  */
  50
  51 #include <sys/param.h>
  52 #include <sys/kernel.h>
  53 #include <sys/systm.h>
  54 #include <sys/thread.h>
  55 #include <sys/globaldata.h>
  56 #include <sys/systimer.h>
  57 #include <sys/thread2.h>
  58
  59 /*
  60  * Execute ready systimers.  Called directly from the platform-specific
  61  * one-shot timer clock interrupt (e.g. clkintr()) or via an IPI.  May
  62  * be called simultaniously on multiple cpus and always operations on
  63  * the current cpu's queue.  Systimer functions are responsible for calling
  64  * hardclock, statclock, and other finely-timed routines.
  65  */
  66 void
  67 systimer_intr(sysclock_t *timep, int dummy, struct intrframe *frame)
  68 {
  69     globaldata_t gd = mycpu;
  70     sysclock_t time = *timep;
  71     systimer_t info;
  72
  73     if (gd->gd_syst_nest)
  74         return;
  75
  76     crit_enter();
  77     ++gd->gd_syst_nest;
  78     while ((info = TAILQ_FIRST(&gd->gd_systimerq)) != NULL) {
  79         /*
  80          * If we haven't reached the requested time, tell the cputimer
  81          * how much is left and break out.
  82          */
  83         if ((int)(info->time - time) > 0) {
  84             cputimer_intr_reload(info->time - time);
  85             break;
  86         }
  87
  88         /*
  89          * Dequeue and execute
  90          */
  91         info->flags &= ~SYSTF_ONQUEUE;
  92         TAILQ_REMOVE(info->queue, info, node);
  93         crit_exit();
  94         info->func(info, frame);
  95         crit_enter();
  96
  97         /*
  98          * Reinstall if periodic.  If this is a non-queued periodic
  99          * interrupt do not allow multiple events to build up (used
 100          * for things like the callout timer to prevent premature timeouts
 101          * due to long interrupt disablements, BIOS 8254 glitching, and so
 102          * forth).  However, we still want to keep things synchronized between
 103          * cpus for efficient handling of the timer interrupt so jump in
 104          * multiples of the periodic rate.
 105          */
 106         if (info->periodic) {
 107             info->time += info->periodic;
 108             if ((info->flags & SYSTF_NONQUEUED) &&
 109                 (int)(info->time - time) <= 0
 110             ) {
 111                 info->time += ((time - info->time + info->periodic - 1) /
 112                                 info->periodic) * info->periodic;
 113             }
 114             systimer_add(info);
 115         }
 116     }
 117     --gd->gd_syst_nest;
 118     crit_exit();
 119 }
 120
 121 void
 122 systimer_add(systimer_t info)
 123 {
 124     struct globaldata *gd = mycpu;
 125
 126     KKASSERT((info->flags & (SYSTF_ONQUEUE|SYSTF_IPIRUNNING)) == 0);
 127     crit_enter();
 128     if (info->gd == gd) {
 129         systimer_t scan1;
 130         systimer_t scan2;
 131         scan1 = TAILQ_FIRST(&gd->gd_systimerq);
 132         if (scan1 == NULL || (int)(scan1->time - info->time) > 0) {
 133             cputimer_intr_reload(info->time - sys_cputimer->count());
 134             TAILQ_INSERT_HEAD(&gd->gd_systimerq, info, node);
 135         } else {
 136             scan2 = TAILQ_LAST(&gd->gd_systimerq, systimerq);
 137             for (;;) {
 138                 if (scan1 == NULL) {
 139                     TAILQ_INSERT_TAIL(&gd->gd_systimerq, info, node);
 140                     break;
 141                 }
 142                 if ((int)(scan1->time - info->time) > 0) {
 143                     TAILQ_INSERT_BEFORE(scan1, info, node);
 144                     break;
 145                 }
 146                 if ((int)(scan2->time - info->time) <= 0) {
 147                     TAILQ_INSERT_AFTER(&gd->gd_systimerq, scan2, info, node);
 148                     break;
 149                 }
 150                 scan1 = TAILQ_NEXT(scan1, node);
 151                 scan2 = TAILQ_PREV(scan2, systimerq, node);
 152             }
 153         }
 154         info->flags = (info->flags | SYSTF_ONQUEUE) & ~SYSTF_IPIRUNNING;
 155         info->queue = &gd->gd_systimerq;
 156     } else {
 157 #ifdef SMP
 158         info->flags |= SYSTF_IPIRUNNING;
 159         lwkt_send_ipiq(info->gd, (ipifunc1_t)systimer_add, info);
 160 #else
 161         panic("systimer_add: bad gd in info %p", info);
 162 #endif
 163     }
 164     crit_exit();
 165 }
 166
 167 /*
 168  * systimer_del()
 169  *
 170  *      Delete a system timer.  Only the owning cpu can delete a timer.
 171  */
 172 void
 173 systimer_del(systimer_t info)
 174 {
 175     KKASSERT(info->gd == mycpu && (info->flags & SYSTF_IPIRUNNING) == 0);
 176     crit_enter();
 177     if (info->flags & SYSTF_ONQUEUE) {
 178         TAILQ_REMOVE(info->queue, info, node);
 179         info->flags &= ~SYSTF_ONQUEUE;
 180     }
 181     crit_exit();
 182 }
 183
 184 /*
 185  * systimer_init_periodic()
 186  *
 187  *      Initialize a periodic timer at the specified frequency and add
 188  *      it to the system.  The frequency is uncompensated and approximate.
 189  *
 190  *      Try to synchronize multi registrations of the same or similar
 191  *      frequencies so the hardware interrupt is able to dispatch several
 192  *      at together by adjusting the phase of the initial interrupt.  This
 193  *      helps SMP.  Note that we are not attempting to synchronize to
 194  *      the realtime clock.
 195  */
 196 void
 197 systimer_init_periodic(systimer_t info, void *func, void *data, int hz)
 198 {
 199     sysclock_t base_count;
 200
 201     bzero(info, sizeof(struct systimer));
 202     info->periodic = sys_cputimer->fromhz(hz);
 203     base_count = sys_cputimer->count();
 204     base_count = base_count - (base_count % info->periodic);
 205     info->time = base_count + info->periodic;
 206     info->func = func;
 207     info->data = data;
 208     info->gd = mycpu;
 209     systimer_add(info);
 210 }
 211
 212 void
 213 systimer_init_periodic_nq(systimer_t info, void *func, void *data, int hz)
 214 {
 215     sysclock_t base_count;
 216
 217     bzero(info, sizeof(struct systimer));
 218     info->periodic = sys_cputimer->fromhz(hz);
 219     base_count = sys_cputimer->count();
 220     base_count = base_count - (base_count % info->periodic);
 221     info->time = base_count + info->periodic;
 222     info->func = func;
 223     info->data = data;
 224     info->gd = mycpu;
 225     info->flags |= SYSTF_NONQUEUED;
 226     systimer_add(info);
 227 }
 228
 229 /*
 230  * systimer_init_oneshot()
 231  *
 232  *      Initialize a periodic timer at the specified frequency and add
 233  *      it to the system.  The frequency is uncompensated and approximate.
 234  */
 235 void
 236 systimer_init_oneshot(systimer_t info, void *func, void *data, int us)
 237 {
 238     bzero(info, sizeof(struct systimer));
 239     info->time = sys_cputimer->count() + sys_cputimer->fromus(us);
 240     info->func = func;
 241     info->data = data;
 242     info->gd = mycpu;
 243     systimer_add(info);
 244 }
 245