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 1.7 2005/06/01 17:43:42 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, 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 info->flags |= SYSTF_IPIRUNNING; 158 lwkt_send_ipiq(info->gd, (ipifunc_t)systimer_add, info); 159 } 160 crit_exit(); 161 } 162 163 /* 164 * systimer_del() 165 * 166 * Delete a system timer. Only the owning cpu can delete a timer. 167 */ 168 void 169 systimer_del(systimer_t info) 170 { 171 KKASSERT(info->gd == mycpu && (info->flags & SYSTF_IPIRUNNING) == 0); 172 crit_enter(); 173 if (info->flags & SYSTF_ONQUEUE) { 174 TAILQ_REMOVE(info->queue, info, node); 175 info->flags &= ~SYSTF_ONQUEUE; 176 } 177 crit_exit(); 178 } 179 180 /* 181 * systimer_init_periodic() 182 * 183 * Initialize a periodic timer at the specified frequency and add 184 * it to the system. The frequency is uncompensated and approximate. 185 * 186 * Try to synchronize multi registrations of the same or similar 187 * frequencies so the hardware interrupt is able to dispatch several 188 * at together by adjusting the phase of the initial interrupt. This 189 * helps SMP. Note that we are not attempting to synchronize to 190 * the realtime clock. 191 */ 192 void 193 systimer_init_periodic(systimer_t info, void *func, void *data, int hz) 194 { 195 sysclock_t base_count; 196 197 bzero(info, sizeof(struct systimer)); 198 info->periodic = sys_cputimer->fromhz(hz); 199 base_count = sys_cputimer->count(); 200 base_count = base_count - (base_count % info->periodic); 201 info->time = base_count + info->periodic; 202 info->func = func; 203 info->data = data; 204 info->gd = mycpu; 205 systimer_add(info); 206 } 207 208 void 209 systimer_init_periodic_nq(systimer_t info, void *func, void *data, int hz) 210 { 211 sysclock_t base_count; 212 213 bzero(info, sizeof(struct systimer)); 214 info->periodic = sys_cputimer->fromhz(hz); 215 base_count = sys_cputimer->count(); 216 base_count = base_count - (base_count % info->periodic); 217 info->time = base_count + info->periodic; 218 info->func = func; 219 info->data = data; 220 info->gd = mycpu; 221 info->flags |= SYSTF_NONQUEUED; 222 systimer_add(info); 223 } 224 225 /* 226 * systimer_init_oneshot() 227 * 228 * Initialize a periodic timer at the specified frequency and add 229 * it to the system. The frequency is uncompensated and approximate. 230 */ 231 void 232 systimer_init_oneshot(systimer_t info, void *func, void *data, int us) 233 { 234 bzero(info, sizeof(struct systimer)); 235 info->time = sys_cputimer->count() + sys_cputimer->fromus(us); 236 info->func = func; 237 info->data = data; 238 info->gd = mycpu; 239 systimer_add(info); 240 } 241 242