1 /*- 2 * Copyright (c) 2000 Doug Rabson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/sys/kern/subr_taskqueue.c,v 1.1.2.3 2003/09/10 00:40:39 ken Exp $ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/queue.h> 31 #include <sys/systm.h> 32 #include <sys/kernel.h> 33 #include <sys/taskqueue.h> 34 #include <sys/interrupt.h> 35 #include <sys/lock.h> 36 #include <sys/malloc.h> 37 #include <sys/kthread.h> 38 #include <sys/thread2.h> 39 #include <sys/spinlock.h> 40 #include <sys/spinlock2.h> 41 #include <sys/serialize.h> 42 #include <sys/proc.h> 43 #include <machine/varargs.h> 44 45 MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 46 47 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 48 static struct lock taskqueue_queues_lock; 49 50 struct taskqueue { 51 STAILQ_ENTRY(taskqueue) tq_link; 52 STAILQ_HEAD(, task) tq_queue; 53 const char *tq_name; 54 taskqueue_enqueue_fn tq_enqueue; 55 void *tq_context; 56 57 struct task *tq_running; 58 struct spinlock tq_lock; 59 struct thread **tq_threads; 60 int tq_tcount; 61 int tq_flags; 62 }; 63 64 #define TQ_FLAGS_ACTIVE (1 << 0) 65 #define TQ_FLAGS_BLOCKED (1 << 1) 66 #define TQ_FLAGS_PENDING (1 << 2) 67 68 static void taskqueue_run(struct taskqueue *queue, int lock_held); 69 70 static __inline void 71 TQ_LOCK_INIT(struct taskqueue *tq) 72 { 73 spin_init(&tq->tq_lock); 74 } 75 76 static __inline void 77 TQ_LOCK_UNINIT(struct taskqueue *tq) 78 { 79 spin_uninit(&tq->tq_lock); 80 } 81 82 static __inline void 83 TQ_LOCK(struct taskqueue *tq) 84 { 85 spin_lock(&tq->tq_lock); 86 } 87 88 static __inline void 89 TQ_UNLOCK(struct taskqueue *tq) 90 { 91 spin_unlock(&tq->tq_lock); 92 } 93 94 static __inline void 95 TQ_SLEEP(struct taskqueue *tq, void *ident, const char *wmesg) 96 { 97 ssleep(ident, &tq->tq_lock, 0, wmesg, 0); 98 } 99 100 struct taskqueue * 101 taskqueue_create(const char *name, int mflags, 102 taskqueue_enqueue_fn enqueue, void *context) 103 { 104 struct taskqueue *queue; 105 106 queue = kmalloc(sizeof(*queue), M_TASKQUEUE, mflags | M_ZERO); 107 if (!queue) 108 return NULL; 109 STAILQ_INIT(&queue->tq_queue); 110 queue->tq_name = name; 111 queue->tq_enqueue = enqueue; 112 queue->tq_context = context; 113 queue->tq_flags |= TQ_FLAGS_ACTIVE; 114 TQ_LOCK_INIT(queue); 115 116 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE); 117 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 118 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 119 120 return queue; 121 } 122 123 static void 124 taskqueue_terminate(struct thread **pp, struct taskqueue *tq) 125 { 126 while(tq->tq_tcount > 0) { 127 wakeup(tq); 128 TQ_SLEEP(tq, pp, "taskqueue_terminate"); 129 } 130 } 131 132 void 133 taskqueue_free(struct taskqueue *queue) 134 { 135 TQ_LOCK(queue); 136 queue->tq_flags &= ~TQ_FLAGS_ACTIVE; 137 taskqueue_run(queue, 1); 138 taskqueue_terminate(queue->tq_threads, queue); 139 TQ_UNLOCK(queue); 140 141 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE); 142 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 143 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 144 145 TQ_LOCK_UNINIT(queue); 146 147 kfree(queue, M_TASKQUEUE); 148 } 149 150 struct taskqueue * 151 taskqueue_find(const char *name) 152 { 153 struct taskqueue *queue; 154 155 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE); 156 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) { 157 if (!strcmp(queue->tq_name, name)) { 158 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 159 return queue; 160 } 161 } 162 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 163 return NULL; 164 } 165 166 /* 167 * NOTE! If using the per-cpu taskqueues ``taskqueue_thread[mycpuid]'', 168 * be sure NOT TO SHARE the ``task'' between CPUs. TASKS ARE NOT LOCKED. 169 * So either use a throwaway task which will only be enqueued once, or 170 * use one task per CPU! 171 */ 172 int 173 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 174 { 175 struct task *ins; 176 struct task *prev; 177 178 TQ_LOCK(queue); 179 180 /* 181 * Don't allow new tasks on a queue which is being freed. 182 */ 183 if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0) { 184 TQ_UNLOCK(queue); 185 return EPIPE; 186 } 187 188 /* 189 * Count multiple enqueues. 190 */ 191 if (task->ta_pending) { 192 task->ta_pending++; 193 TQ_UNLOCK(queue); 194 return 0; 195 } 196 197 /* 198 * Optimise the case when all tasks have the same priority. 199 */ 200 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 201 if (!prev || prev->ta_priority >= task->ta_priority) { 202 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 203 } else { 204 prev = NULL; 205 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 206 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 207 if (ins->ta_priority < task->ta_priority) 208 break; 209 210 if (prev) 211 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 212 else 213 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 214 } 215 216 task->ta_pending = 1; 217 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) { 218 if (queue->tq_enqueue) 219 queue->tq_enqueue(queue->tq_context); 220 } else { 221 queue->tq_flags |= TQ_FLAGS_PENDING; 222 } 223 224 TQ_UNLOCK(queue); 225 226 return 0; 227 } 228 229 void 230 taskqueue_block(struct taskqueue *queue) 231 { 232 TQ_LOCK(queue); 233 queue->tq_flags |= TQ_FLAGS_BLOCKED; 234 TQ_UNLOCK(queue); 235 } 236 237 void 238 taskqueue_unblock(struct taskqueue *queue) 239 { 240 TQ_LOCK(queue); 241 queue->tq_flags &= ~TQ_FLAGS_BLOCKED; 242 if (queue->tq_flags & TQ_FLAGS_PENDING) { 243 queue->tq_flags &= ~TQ_FLAGS_PENDING; 244 if (queue->tq_enqueue) 245 queue->tq_enqueue(queue->tq_context); 246 } 247 TQ_UNLOCK(queue); 248 } 249 250 void 251 taskqueue_run(struct taskqueue *queue, int lock_held) 252 { 253 struct task *task; 254 int pending; 255 256 if (lock_held == 0) 257 TQ_LOCK(queue); 258 while (STAILQ_FIRST(&queue->tq_queue)) { 259 /* 260 * Carefully remove the first task from the queue and 261 * zero its pending count. 262 */ 263 task = STAILQ_FIRST(&queue->tq_queue); 264 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 265 pending = task->ta_pending; 266 task->ta_pending = 0; 267 queue->tq_running = task; 268 TQ_UNLOCK(queue); 269 270 task->ta_func(task->ta_context, pending); 271 272 TQ_LOCK(queue); 273 queue->tq_running = NULL; 274 wakeup(task); 275 } 276 if (lock_held == 0) 277 TQ_UNLOCK(queue); 278 } 279 280 void 281 taskqueue_drain(struct taskqueue *queue, struct task *task) 282 { 283 TQ_LOCK(queue); 284 while (task->ta_pending != 0 || task == queue->tq_running) 285 TQ_SLEEP(queue, task, "-"); 286 TQ_UNLOCK(queue); 287 } 288 289 static void 290 taskqueue_swi_enqueue(void *context) 291 { 292 setsofttq(); 293 } 294 295 static void 296 taskqueue_swi_run(void *arg, void *frame) 297 { 298 taskqueue_run(taskqueue_swi, 0); 299 } 300 301 static void 302 taskqueue_swi_mp_run(void *arg, void *frame) 303 { 304 taskqueue_run(taskqueue_swi_mp, 0); 305 } 306 307 int 308 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, int ncpu, 309 const char *fmt, ...) 310 { 311 __va_list ap; 312 struct thread *td; 313 struct taskqueue *tq; 314 int i, error, cpu; 315 char ktname[MAXCOMLEN]; 316 317 if (count <= 0) 318 return EINVAL; 319 320 tq = *tqp; 321 cpu = ncpu; 322 323 __va_start(ap, fmt); 324 kvsnprintf(ktname, MAXCOMLEN, fmt, ap); 325 __va_end(ap); 326 327 tq->tq_threads = kmalloc(sizeof(struct thread *) * count, M_TASKQUEUE, 328 M_WAITOK | M_ZERO); 329 330 for (i = 0; i < count; i++) { 331 /* 332 * If no specific cpu was specified and more than one thread 333 * is to be created, we distribute the threads amongst all 334 * cpus. 335 */ 336 if ((ncpu <= -1) && (count > 1)) 337 cpu = i%ncpus; 338 339 if (count == 1) { 340 error = lwkt_create(taskqueue_thread_loop, tqp, 341 &tq->tq_threads[i], NULL, 342 TDF_NOSTART, cpu, 343 "%s", ktname); 344 } else { 345 error = lwkt_create(taskqueue_thread_loop, tqp, 346 &tq->tq_threads[i], NULL, 347 TDF_NOSTART, cpu, 348 "%s_%d", ktname, i); 349 } 350 if (error) { 351 kprintf("%s: lwkt_create(%s): error %d", __func__, 352 ktname, error); 353 tq->tq_threads[i] = NULL; 354 } else { 355 td = tq->tq_threads[i]; 356 lwkt_setpri_initial(td, pri); 357 lwkt_schedule(td); 358 tq->tq_tcount++; 359 } 360 } 361 362 return 0; 363 } 364 365 void 366 taskqueue_thread_loop(void *arg) 367 { 368 struct taskqueue **tqp, *tq; 369 370 tqp = arg; 371 tq = *tqp; 372 TQ_LOCK(tq); 373 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) { 374 taskqueue_run(tq, 1); 375 TQ_SLEEP(tq, tq, "tqthr"); 376 } 377 378 /* rendezvous with thread that asked us to terminate */ 379 tq->tq_tcount--; 380 wakeup_one(tq->tq_threads); 381 TQ_UNLOCK(tq); 382 lwkt_exit(); 383 } 384 385 void 386 taskqueue_thread_enqueue(void *context) 387 { 388 struct taskqueue **tqp, *tq; 389 390 tqp = context; 391 tq = *tqp; 392 393 wakeup_one(tq); 394 } 395 396 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 397 register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL, -1)); 398 /* 399 * XXX: possibly use a different SWI_TQ_MP or so. 400 * related: sys/interrupt.h 401 * related: platform/XXX/isa/ipl_funcs.c 402 */ 403 TASKQUEUE_DEFINE(swi_mp, taskqueue_swi_enqueue, 0, 404 register_swi_mp(SWI_TQ, taskqueue_swi_mp_run, NULL, "swi_mp_taskq", NULL, 405 -1)); 406 407 struct taskqueue *taskqueue_thread[MAXCPU]; 408 409 static void 410 taskqueue_init(void) 411 { 412 int cpu; 413 414 lockinit(&taskqueue_queues_lock, "tqqueues", 0, 0); 415 STAILQ_INIT(&taskqueue_queues); 416 417 for (cpu = 0; cpu < ncpus; cpu++) { 418 taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT, 419 taskqueue_thread_enqueue, &taskqueue_thread[cpu]); 420 taskqueue_start_threads(&taskqueue_thread[cpu], 1, 421 TDPRI_KERN_DAEMON, cpu, "taskq_cpu %d", cpu); 422 } 423 } 424 425 SYSINIT(taskqueueinit, SI_SUB_PRE_DRIVERS, SI_ORDER_ANY, taskqueue_init, NULL); 426