sys/kern/subr_taskqueue.c

   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 1.69 2012/08/28 13:35:37 jhb 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         /* NOTE: tq must be locked before calling tq_enqueue */
  55         taskqueue_enqueue_fn    tq_enqueue;
  56         void                    *tq_context;
  57
  58         struct task             *tq_running;
  59         struct spinlock         tq_lock;
  60         struct thread           **tq_threads;
  61         int                     tq_tcount;
  62         int                     tq_flags;
  63         int                     tq_callouts;
  64 };
  65
  66 #define TQ_FLAGS_ACTIVE         (1 << 0)
  67 #define TQ_FLAGS_BLOCKED        (1 << 1)
  68 #define TQ_FLAGS_PENDING        (1 << 2)
  69
  70 #define DT_CALLOUT_ARMED        (1 << 0)
  71
  72 void
  73 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
  74     int priority, task_fn_t func, void *context)
  75 {
  76
  77         TASK_INIT(&timeout_task->t, priority, func, context);
  78         callout_init(&timeout_task->c); /* XXX use callout_init_mp() */
  79         timeout_task->q = queue;
  80         timeout_task->f = 0;
  81 }
  82
  83 static void taskqueue_run(struct taskqueue *queue, int lock_held);
  84
  85 static __inline void
  86 TQ_LOCK_INIT(struct taskqueue *tq)
  87 {
  88         spin_init(&tq->tq_lock, "tqlock");
  89 }
  90
  91 static __inline void
  92 TQ_LOCK_UNINIT(struct taskqueue *tq)
  93 {
  94         spin_uninit(&tq->tq_lock);
  95 }
  96
  97 static __inline void
  98 TQ_LOCK(struct taskqueue *tq)
  99 {
 100         spin_lock(&tq->tq_lock);
 101 }
 102
 103 static __inline void
 104 TQ_UNLOCK(struct taskqueue *tq)
 105 {
 106         spin_unlock(&tq->tq_lock);
 107 }
 108
 109 static __inline void
 110 TQ_SLEEP(struct taskqueue *tq, void *ident, const char *wmesg)
 111 {
 112         ssleep(ident, &tq->tq_lock, 0, wmesg, 0);
 113 }
 114
 115 struct taskqueue *
 116 taskqueue_create(const char *name, int mflags,
 117                  taskqueue_enqueue_fn enqueue, void *context)
 118 {
 119         struct taskqueue *queue;
 120
 121         queue = kmalloc(sizeof(*queue), M_TASKQUEUE, mflags | M_ZERO);
 122         if (!queue)
 123                 return NULL;
 124         STAILQ_INIT(&queue->tq_queue);
 125         queue->tq_name = name;
 126         queue->tq_enqueue = enqueue;
 127         queue->tq_context = context;
 128         queue->tq_flags |= TQ_FLAGS_ACTIVE;
 129         TQ_LOCK_INIT(queue);
 130
 131         lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
 132         STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
 133         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
 134
 135         return queue;
 136 }
 137
 138 /* NOTE: tq must be locked */
 139 static void
 140 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
 141 {
 142         while(tq->tq_tcount > 0) {
 143                 /* Unlock spinlock before wakeup() */
 144                 TQ_UNLOCK(tq);
 145                 wakeup(tq);
 146                 TQ_LOCK(tq);
 147                 TQ_SLEEP(tq, pp, "taskqueue_terminate");
 148         }
 149 }
 150
 151 void
 152 taskqueue_free(struct taskqueue *queue)
 153 {
 154         TQ_LOCK(queue);
 155         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
 156         taskqueue_run(queue, 1);
 157         taskqueue_terminate(queue->tq_threads, queue);
 158         TQ_UNLOCK(queue);
 159
 160         lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
 161         STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
 162         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
 163
 164         TQ_LOCK_UNINIT(queue);
 165
 166         kfree(queue, M_TASKQUEUE);
 167 }
 168
 169 struct taskqueue *
 170 taskqueue_find(const char *name)
 171 {
 172         struct taskqueue *queue;
 173
 174         lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
 175         STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) {
 176                 if (!strcmp(queue->tq_name, name)) {
 177                         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
 178                         return queue;
 179                 }
 180         }
 181         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
 182         return NULL;
 183 }
 184
 185 /*
 186  * NOTE!  If using the per-cpu taskqueues ``taskqueue_thread[mycpuid]'',
 187  * be sure NOT TO SHARE the ``task'' between CPUs.  TASKS ARE NOT LOCKED.
 188  * So either use a throwaway task which will only be enqueued once, or
 189  * use one task per CPU!
 190  */
 191 static int
 192 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
 193 {
 194         struct task *ins;
 195         struct task *prev;
 196
 197         /*
 198          * Don't allow new tasks on a queue which is being freed.
 199          */
 200         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 201                 return EPIPE;
 202
 203         /*
 204          * Count multiple enqueues.
 205          */
 206         if (task->ta_pending) {
 207                 task->ta_pending++;
 208                 return 0;
 209         }
 210
 211         /*
 212          * Optimise the case when all tasks have the same priority.
 213          */
 214         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 215         if (!prev || prev->ta_priority >= task->ta_priority) {
 216                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
 217         } else {
 218                 prev = NULL;
 219                 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
 220                      prev = ins, ins = STAILQ_NEXT(ins, ta_link))
 221                         if (ins->ta_priority < task->ta_priority)
 222                                 break;
 223
 224                 if (prev)
 225                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
 226                 else
 227                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
 228         }
 229
 230         task->ta_pending = 1;
 231         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) {
 232                 if (queue->tq_enqueue)
 233                         queue->tq_enqueue(queue->tq_context);
 234         } else {
 235                 queue->tq_flags |= TQ_FLAGS_PENDING;
 236         }
 237
 238         return 0;
 239 }
 240
 241 int
 242 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
 243 {
 244         int res;
 245
 246         TQ_LOCK(queue);
 247         res = taskqueue_enqueue_locked(queue, task);
 248         TQ_UNLOCK(queue);
 249
 250         return (res);
 251 }
 252
 253 static void
 254 taskqueue_timeout_func(void *arg)
 255 {
 256         struct taskqueue *queue;
 257         struct timeout_task *timeout_task;
 258
 259         timeout_task = arg;
 260         queue = timeout_task->q;
 261
 262         TQ_LOCK(queue);
 263         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
 264         timeout_task->f &= ~DT_CALLOUT_ARMED;
 265         queue->tq_callouts--;
 266         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
 267         TQ_UNLOCK(queue);
 268 }
 269
 270 int
 271 taskqueue_enqueue_timeout(struct taskqueue *queue,
 272     struct timeout_task *timeout_task, int ticks)
 273 {
 274         int res;
 275
 276         TQ_LOCK(queue);
 277         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
 278                 ("Migrated queue"));
 279         timeout_task->q = queue;
 280         res = timeout_task->t.ta_pending;
 281         if (ticks == 0) {
 282                 taskqueue_enqueue_locked(queue, &timeout_task->t);
 283                 TQ_UNLOCK(queue);
 284         } else {
 285                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 286                         res++;
 287                 } else {
 288                         queue->tq_callouts++;
 289                         timeout_task->f |= DT_CALLOUT_ARMED;
 290                 }
 291                 TQ_UNLOCK(queue);
 292                 callout_reset(&timeout_task->c, ticks, taskqueue_timeout_func,
 293                               timeout_task);
 294         }
 295         return (res);
 296 }
 297
 298 void
 299 taskqueue_block(struct taskqueue *queue)
 300 {
 301         TQ_LOCK(queue);
 302         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 303         TQ_UNLOCK(queue);
 304 }
 305
 306 void
 307 taskqueue_unblock(struct taskqueue *queue)
 308 {
 309         TQ_LOCK(queue);
 310         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 311         if (queue->tq_flags & TQ_FLAGS_PENDING) {
 312                 queue->tq_flags &= ~TQ_FLAGS_PENDING;
 313                 if (queue->tq_enqueue)
 314                         queue->tq_enqueue(queue->tq_context);
 315         }
 316         TQ_UNLOCK(queue);
 317 }
 318
 319 static void
 320 taskqueue_run(struct taskqueue *queue, int lock_held)
 321 {
 322         struct task *task;
 323         int pending;
 324
 325         if (lock_held == 0)
 326                 TQ_LOCK(queue);
 327         while (STAILQ_FIRST(&queue->tq_queue)) {
 328                 /*
 329                  * Carefully remove the first task from the queue and
 330                  * zero its pending count.
 331                  */
 332                 task = STAILQ_FIRST(&queue->tq_queue);
 333                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 334                 pending = task->ta_pending;
 335                 task->ta_pending = 0;
 336                 queue->tq_running = task;
 337
 338                 TQ_UNLOCK(queue);
 339                 task->ta_func(task->ta_context, pending);
 340                 queue->tq_running = NULL;
 341                 wakeup(task);
 342                 TQ_LOCK(queue);
 343         }
 344         if (lock_held == 0)
 345                 TQ_UNLOCK(queue);
 346 }
 347
 348 static int
 349 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 350     u_int *pendp)
 351 {
 352
 353         if (task->ta_pending > 0)
 354                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 355         if (pendp != NULL)
 356                 *pendp = task->ta_pending;
 357         task->ta_pending = 0;
 358         return (task == queue->tq_running ? EBUSY : 0);
 359 }
 360
 361 int
 362 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 363 {
 364         int error;
 365
 366         TQ_LOCK(queue);
 367         error = taskqueue_cancel_locked(queue, task, pendp);
 368         TQ_UNLOCK(queue);
 369
 370         return (error);
 371 }
 372
 373 int
 374 taskqueue_cancel_timeout(struct taskqueue *queue,
 375                          struct timeout_task *timeout_task, u_int *pendp)
 376 {
 377         u_int pending, pending1;
 378         int error;
 379
 380         pending = !!callout_stop(&timeout_task->c);
 381         TQ_LOCK(queue);
 382         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 383         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 384                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 385                 queue->tq_callouts--;
 386         }
 387         TQ_UNLOCK(queue);
 388
 389         if (pendp != NULL)
 390                 *pendp = pending + pending1;
 391         return (error);
 392 }
 393
 394 void
 395 taskqueue_drain(struct taskqueue *queue, struct task *task)
 396 {
 397         TQ_LOCK(queue);
 398         while (task->ta_pending != 0 || task == queue->tq_running)
 399                 TQ_SLEEP(queue, task, "-");
 400         TQ_UNLOCK(queue);
 401 }
 402
 403 void
 404 taskqueue_drain_timeout(struct taskqueue *queue,
 405     struct timeout_task *timeout_task)
 406 {
 407
 408         callout_stop_sync(&timeout_task->c);
 409         taskqueue_drain(queue, &timeout_task->t);
 410 }
 411
 412 static void
 413 taskqueue_swi_enqueue(void *context)
 414 {
 415         setsofttq();
 416 }
 417
 418 static void
 419 taskqueue_swi_run(void *arg, void *frame)
 420 {
 421         taskqueue_run(taskqueue_swi, 0);
 422 }
 423
 424 static void
 425 taskqueue_swi_mp_run(void *arg, void *frame)
 426 {
 427         taskqueue_run(taskqueue_swi_mp, 0);
 428 }
 429
 430 int
 431 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, int ncpu,
 432                         const char *fmt, ...)
 433 {
 434         __va_list ap;
 435         struct thread *td;
 436         struct taskqueue *tq;
 437         int i, error, cpu;
 438         char ktname[MAXCOMLEN];
 439
 440         if (count <= 0)
 441                 return EINVAL;
 442
 443         tq = *tqp;
 444         cpu = ncpu;
 445
 446         __va_start(ap, fmt);
 447         kvsnprintf(ktname, MAXCOMLEN, fmt, ap);
 448         __va_end(ap);
 449
 450         tq->tq_threads = kmalloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 451             M_WAITOK | M_ZERO);
 452
 453         for (i = 0; i < count; i++) {
 454                 /*
 455                  * If no specific cpu was specified and more than one thread
 456                  * is to be created, we distribute the threads amongst all
 457                  * cpus.
 458                  */
 459                 if ((ncpu <= -1) && (count > 1))
 460                         cpu = i%ncpus;
 461
 462                 if (count == 1) {
 463                         error = lwkt_create(taskqueue_thread_loop, tqp,
 464                                             &tq->tq_threads[i], NULL,
 465                                             TDF_NOSTART, cpu,
 466                                             "%s", ktname);
 467                 } else {
 468                         error = lwkt_create(taskqueue_thread_loop, tqp,
 469                                             &tq->tq_threads[i], NULL,
 470                                             TDF_NOSTART, cpu,
 471                                             "%s_%d", ktname, i);
 472                 }
 473                 if (error) {
 474                         kprintf("%s: lwkt_create(%s): error %d", __func__,
 475                             ktname, error);
 476                         tq->tq_threads[i] = NULL;
 477                 } else {
 478                         td = tq->tq_threads[i];
 479                         lwkt_setpri_initial(td, pri);
 480                         lwkt_schedule(td);
 481                         tq->tq_tcount++;
 482                 }
 483         }
 484
 485         return 0;
 486 }
 487
 488 void
 489 taskqueue_thread_loop(void *arg)
 490 {
 491         struct taskqueue **tqp, *tq;
 492
 493         tqp = arg;
 494         tq = *tqp;
 495         TQ_LOCK(tq);
 496         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 497                 taskqueue_run(tq, 1);
 498                 TQ_SLEEP(tq, tq, "tqthr");
 499         }
 500
 501         /* rendezvous with thread that asked us to terminate */
 502         tq->tq_tcount--;
 503         TQ_UNLOCK(tq);
 504         wakeup_one(tq->tq_threads);
 505         lwkt_exit();
 506 }
 507
 508 /* NOTE: tq must be locked */
 509 void
 510 taskqueue_thread_enqueue(void *context)
 511 {
 512         struct taskqueue **tqp, *tq;
 513
 514         tqp = context;
 515         tq = *tqp;
 516
 517         /* Unlock spinlock before wakeup_one() */
 518         TQ_UNLOCK(tq);
 519         wakeup_one(tq);
 520         TQ_LOCK(tq);
 521 }
 522
 523 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
 524          register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL, -1));
 525 /*
 526  * XXX: possibly use a different SWI_TQ_MP or so.
 527  * related: sys/interrupt.h
 528  * related: platform/XXX/isa/ipl_funcs.c
 529  */
 530 TASKQUEUE_DEFINE(swi_mp, taskqueue_swi_enqueue, 0,
 531     register_swi_mp(SWI_TQ, taskqueue_swi_mp_run, NULL, "swi_mp_taskq", NULL,
 532                     -1));
 533
 534 struct taskqueue *taskqueue_thread[MAXCPU];
 535
 536 static void
 537 taskqueue_init(void)
 538 {
 539         int cpu;
 540
 541         lockinit(&taskqueue_queues_lock, "tqqueues", 0, 0);
 542         STAILQ_INIT(&taskqueue_queues);
 543
 544         for (cpu = 0; cpu < ncpus; cpu++) {
 545                 taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT,
 546                     taskqueue_thread_enqueue, &taskqueue_thread[cpu]);
 547                 taskqueue_start_threads(&taskqueue_thread[cpu], 1,
 548                     TDPRI_KERN_DAEMON, cpu, "taskq_cpu %d", cpu);
 549         }
 550 }
 551
 552 SYSINIT(taskqueueinit, SI_SUB_PRE_DRIVERS, SI_ORDER_ANY, taskqueue_init, NULL);