1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #include <signal.h> 28 #include <strings.h> 29 #include <limits.h> 30 31 #include <fmd_alloc.h> 32 #include <fmd_subr.h> 33 #include <fmd_thread.h> 34 #include <fmd_timerq.h> 35 36 #include <fmd.h> 37 38 /* 39 * Install a new timer to fire after at least 'delta' nanoseconds have elapsed. 40 * Timers are associated with persistent integer identifiers in some idspace. 41 * We allocate a new timer structure or re-use one from our freelist, and then 42 * place it on the queue's list in sorted order by expiration time. If the new 43 * timer is now the earliest to expire, we awaken the fmd_timerq_exec() thread. 44 */ 45 id_t 46 fmd_timerq_install(fmd_timerq_t *tmq, fmd_idspace_t *ids, 47 fmd_timer_f *func, void *arg, fmd_event_t *ep, hrtime_t delta) 48 { 49 hrtime_t now = fmd_time_gethrtime(); 50 hrtime_t base = ep ? fmd_event_hrtime(ep) : now; 51 52 fmd_timer_t *tp, *up; 53 hrtime_t hrt; 54 id_t id; 55 56 (void) pthread_mutex_lock(&tmq->tmq_lock); 57 58 if ((tp = fmd_list_next(&tmq->tmq_free)) == NULL) { 59 tp = fmd_zalloc(sizeof (fmd_timer_t), FMD_SLEEP); 60 (void) pthread_cond_init(&tp->tmr_cv, NULL); 61 } else 62 fmd_list_delete(&tmq->tmq_free, tp); 63 64 if ((id = fmd_idspace_alloc(ids, tp)) == -1) { 65 fmd_list_prepend(&tmq->tmq_free, tp); 66 (void) pthread_mutex_unlock(&tmq->tmq_lock); 67 return (id); 68 } 69 70 if (delta < 0) 71 delta = 0; /* ensure delta is at least 0ns from now */ 72 73 if (base + delta < base) 74 hrt = INT64_MAX; /* if wrap-around, set timer for apocalypse */ 75 else 76 hrt = base + delta; 77 78 tp->tmr_hrt = hrt; 79 tp->tmr_ids = ids; 80 tp->tmr_id = id; 81 tp->tmr_func = func; 82 tp->tmr_arg = arg; 83 84 /* 85 * For now we use a simple insertion sort for tmq_list. If we have 86 * scaling problems here due to heavy use of our timer subsystem, 87 * then tmq_list can and should be replaced with a O(logN) heap. 88 */ 89 for (up = fmd_list_next(&tmq->tmq_list); up; up = fmd_list_next(up)) { 90 if (tp->tmr_hrt < up->tmr_hrt) 91 break; 92 } 93 94 if (up != NULL) 95 fmd_list_insert_before(&tmq->tmq_list, up, tp); 96 else 97 fmd_list_insert_after(&tmq->tmq_list, up, tp); 98 99 if (up != NULL && fmd_list_next(&tmq->tmq_list) == tp) 100 fmd_time_waitcancel(tmq->tmq_thread->thr_tid); 101 else if (up == NULL && fmd_list_next(&tmq->tmq_list) == tp) 102 (void) pthread_cond_signal(&tmq->tmq_cv); 103 104 (void) pthread_mutex_unlock(&tmq->tmq_lock); 105 106 TRACE((FMD_DBG_TMR, "timer %s:%ld insert +%lldns", 107 ids->ids_name, id, delta)); 108 109 return (id); 110 } 111 112 /* 113 * Remove the specified timer. If the 'id' is invalid, we'll panic inside of 114 * fmd_idspace_free(). If the timer is still set, we move it to the freelist 115 * and update the timer thread as needed. If the timer 'id' is valid but 116 * tmr_id is not equal to id, then the timer callback is running: we wait for 117 * tmr_id to change to zero (indicating tmr_func is done) before returning. 118 */ 119 void * 120 fmd_timerq_remove(fmd_timerq_t *tmq, fmd_idspace_t *ids, id_t id) 121 { 122 hrtime_t delta = 0; 123 void *arg = NULL; 124 fmd_timer_t *tp; 125 126 (void) pthread_mutex_lock(&tmq->tmq_lock); 127 tp = fmd_idspace_free(ids, id); 128 ASSERT(tp == NULL || tp->tmr_ids == ids); 129 130 if (tp == NULL) { 131 (void) pthread_mutex_unlock(&tmq->tmq_lock); 132 return (NULL); /* timer is no longer active */ 133 } 134 135 if (tp->tmr_id == id) { 136 fmd_list_delete(&tmq->tmq_list, tp); 137 delta = tp->tmr_hrt - fmd_time_gethrtime(); 138 arg = tp->tmr_arg; 139 tp->tmr_id = 0; 140 fmd_list_append(&tmq->tmq_free, tp); 141 142 /* 143 * If tmq_list is now empty, we must awaken the exec thread so 144 * it will sleep on tmq_cv waiting for the list to change. We 145 * could also awaken the exec thread if we removed the head of 146 * tmq_list, but an early wakeup is harmless so we do nothing. 147 */ 148 if (fmd_list_next(&tmq->tmq_list) == NULL) 149 fmd_time_waitcancel(tmq->tmq_thread->thr_tid); 150 } else { 151 /* 152 * Wait until tmr_id is zero, indicating that tmr_func is done. 153 * This relies on expired fmd_timer_t's being returned to our 154 * free list rather than having the data structure deallocated. 155 */ 156 while (tp->tmr_id != 0) 157 (void) pthread_cond_wait(&tp->tmr_cv, &tmq->tmq_lock); 158 } 159 160 (void) pthread_mutex_unlock(&tmq->tmq_lock); 161 162 TRACE((FMD_DBG_TMR, "timer %s:%ld remove -%lldns", 163 ids->ids_name, id, delta > 0 ? delta : 0LL)); 164 165 return (arg); 166 } 167 168 /* 169 * fmd_timerq_exec() is the main loop of the thread that runs the timer queue. 170 * We sleep on tmq_cv waiting for timers to show up on tmq_list. When the list 171 * is non-empty, we execute the callback function for each expired timer. If 172 * timers remain that are not yet expired, we nanosleep() until the next expiry 173 * time. We awaken whenever nanosleep() expires or we are interrupted by a 174 * SIGALRM from fmd_timerq_install indicating that we need to rescan our list. 175 */ 176 static void 177 fmd_timerq_exec(fmd_timerq_t *tmq) 178 { 179 fmd_timer_t *tp; 180 sigset_t set; 181 hrtime_t now; 182 183 /* 184 * fmd_thread_create() initializes threads with all signals blocked. 185 * We must unblock SIGALRM (whose disposition has been to set to call 186 * an empty function by fmd_timerq_init()) in order to permit directed 187 * signals to interrupt our nanosleep() and make it return EINTR. 188 * This SIGALRM mechanism is used by the native clock (see fmd_time.c). 189 */ 190 (void) sigemptyset(&set); 191 (void) sigaddset(&set, SIGALRM); 192 (void) pthread_sigmask(SIG_UNBLOCK, &set, NULL); 193 (void) pthread_mutex_lock(&tmq->tmq_lock); 194 195 for (;;) { 196 while (!tmq->tmq_abort && fmd_list_next(&tmq->tmq_list) == NULL) 197 (void) pthread_cond_wait(&tmq->tmq_cv, &tmq->tmq_lock); 198 199 if (tmq->tmq_abort) { 200 (void) pthread_mutex_unlock(&tmq->tmq_lock); 201 return; /* abort timerq thread */ 202 } 203 204 for (now = fmd_time_gethrtime(); (tp = fmd_list_next( 205 &tmq->tmq_list)) != NULL; now = fmd_time_gethrtime()) { 206 207 if (now == INT64_MAX || tp->tmr_hrt > now) 208 break; /* no more timers left to expire */ 209 210 tp->tmr_id = -tp->tmr_id; 211 fmd_list_delete(&tmq->tmq_list, tp); 212 (void) pthread_mutex_unlock(&tmq->tmq_lock); 213 214 TRACE((FMD_DBG_TMR, "tmr %s:%ld exec start (hrt=%llx)", 215 tp->tmr_ids->ids_name, -tp->tmr_id, tp->tmr_hrt)); 216 217 tp->tmr_func(tp->tmr_arg, -tp->tmr_id, tp->tmr_hrt); 218 219 TRACE((FMD_DBG_TMR, "tmr %s:%ld exec end", 220 tp->tmr_ids->ids_name, -tp->tmr_id)); 221 222 (void) pthread_mutex_lock(&tmq->tmq_lock); 223 (void) fmd_idspace_free(tp->tmr_ids, -tp->tmr_id); 224 fmd_list_append(&tmq->tmq_free, tp); 225 tp->tmr_id = 0; /* for fmd_timer_remove() */ 226 227 (void) pthread_cond_broadcast(&tp->tmr_cv); 228 } 229 230 if (tp != NULL) { 231 (void) pthread_mutex_unlock(&tmq->tmq_lock); 232 fmd_time_waithrtime(tp->tmr_hrt - now); 233 (void) pthread_mutex_lock(&tmq->tmq_lock); 234 } 235 } 236 } 237 238 static void 239 fmd_timerq_alrm(int sig) 240 { 241 TRACE((FMD_DBG_TMR, "timer thread received alarm sig#%d", sig)); 242 } 243 244 fmd_timerq_t * 245 fmd_timerq_create(void) 246 { 247 fmd_timerq_t *tmq = fmd_zalloc(sizeof (fmd_timerq_t), FMD_SLEEP); 248 struct sigaction act; 249 250 (void) pthread_mutex_init(&tmq->tmq_lock, NULL); 251 (void) pthread_cond_init(&tmq->tmq_cv, NULL); 252 253 act.sa_handler = fmd_timerq_alrm; 254 act.sa_flags = 0; 255 (void) sigemptyset(&act.sa_mask); 256 (void) sigaction(SIGALRM, &act, NULL); 257 258 if ((tmq->tmq_thread = fmd_thread_create(fmd.d_rmod, 259 (fmd_thread_f *)fmd_timerq_exec, tmq)) == NULL) 260 fmd_panic("failed to create timer thread"); 261 262 return (tmq); 263 } 264 265 void 266 fmd_timerq_destroy(fmd_timerq_t *tmq) 267 { 268 struct sigaction act; 269 fmd_timer_t *tmr; 270 271 (void) pthread_mutex_lock(&tmq->tmq_lock); 272 tmq->tmq_abort++; 273 274 if (fmd_list_next(&tmq->tmq_list) != NULL) 275 fmd_time_waitcancel(tmq->tmq_thread->thr_tid); 276 else 277 (void) pthread_cond_signal(&tmq->tmq_cv); 278 279 (void) pthread_mutex_unlock(&tmq->tmq_lock); 280 fmd_thread_destroy(tmq->tmq_thread, FMD_THREAD_JOIN); 281 (void) pthread_mutex_lock(&tmq->tmq_lock); 282 283 while ((tmr = fmd_list_next(&tmq->tmq_list)) != NULL) { 284 fmd_list_delete(&tmq->tmq_list, tmr); 285 (void) fmd_idspace_free(tmr->tmr_ids, tmr->tmr_id); 286 fmd_free(tmr, sizeof (fmd_timer_t)); 287 } 288 289 while ((tmr = fmd_list_next(&tmq->tmq_free)) != NULL) { 290 fmd_list_delete(&tmq->tmq_free, tmr); 291 ASSERT(tmr->tmr_id == 0); 292 fmd_free(tmr, sizeof (fmd_timer_t)); 293 } 294 295 act.sa_handler = SIG_DFL; 296 act.sa_flags = 0; 297 (void) sigemptyset(&act.sa_mask); 298 (void) sigaction(SIGALRM, &act, NULL); 299 300 fmd_free(tmq, sizeof (fmd_timerq_t)); 301 } 302