sys/kern/subr_gtaskqueue.c

   1 /*-
   2  * Copyright (c) 2000 Doug Rabson
   3  * Copyright (c) 2014 Jeff Roberson
   4  * Copyright (c) 2016 Matthew Macy
   5  * All rights reserved.
   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  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #include <sys/param.h>
  33 #include <sys/systm.h>
  34 #include <sys/bus.h>
  35 #include <sys/cpuset.h>
  36 #include <sys/kernel.h>
  37 #include <sys/kthread.h>
  38 #include <sys/libkern.h>
  39 #include <sys/limits.h>
  40 #include <sys/lock.h>
  41 #include <sys/malloc.h>
  42 #include <sys/mutex.h>
  43 #include <sys/proc.h>
  44 #include <sys/epoch.h>
  45 #include <sys/sched.h>
  46 #include <sys/smp.h>
  47 #include <sys/gtaskqueue.h>
  48 #include <sys/unistd.h>
  49 #include <machine/stdarg.h>
  50
  51 static MALLOC_DEFINE(M_GTASKQUEUE, "gtaskqueue", "Group Task Queues");
  52 static void     gtaskqueue_thread_enqueue(void *);
  53 static void     gtaskqueue_thread_loop(void *arg);
  54 static int      task_is_running(struct gtaskqueue *queue, struct gtask *gtask);
  55 static void     gtaskqueue_drain_locked(struct gtaskqueue *queue, struct gtask *gtask);
  56
  57 TASKQGROUP_DEFINE(softirq, mp_ncpus, 1);
  58
  59 struct gtaskqueue_busy {
  60         struct gtask            *tb_running;
  61         u_int                    tb_seq;
  62         LIST_ENTRY(gtaskqueue_busy) tb_link;
  63 };
  64
  65 typedef void (*gtaskqueue_enqueue_fn)(void *context);
  66
  67 struct gtaskqueue {
  68         STAILQ_HEAD(, gtask)    tq_queue;
  69         LIST_HEAD(, gtaskqueue_busy) tq_active;
  70         u_int                   tq_seq;
  71         int                     tq_callouts;
  72         struct mtx_padalign     tq_mutex;
  73         gtaskqueue_enqueue_fn   tq_enqueue;
  74         void                    *tq_context;
  75         char                    *tq_name;
  76         struct thread           **tq_threads;
  77         int                     tq_tcount;
  78         int                     tq_spin;
  79         int                     tq_flags;
  80         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
  81         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
  82 };
  83
  84 #define TQ_FLAGS_ACTIVE         (1 << 0)
  85 #define TQ_FLAGS_BLOCKED        (1 << 1)
  86 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
  87
  88 #define DT_CALLOUT_ARMED        (1 << 0)
  89
  90 #define TQ_LOCK(tq)                                                     \
  91         do {                                                            \
  92                 if ((tq)->tq_spin)                                      \
  93                         mtx_lock_spin(&(tq)->tq_mutex);                 \
  94                 else                                                    \
  95                         mtx_lock(&(tq)->tq_mutex);                      \
  96         } while (0)
  97 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
  98
  99 #define TQ_UNLOCK(tq)                                                   \
 100         do {                                                            \
 101                 if ((tq)->tq_spin)                                      \
 102                         mtx_unlock_spin(&(tq)->tq_mutex);               \
 103                 else                                                    \
 104                         mtx_unlock(&(tq)->tq_mutex);                    \
 105         } while (0)
 106 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
 107
 108 #ifdef INVARIANTS
 109 static void
 110 gtask_dump(struct gtask *gtask)
 111 {
 112         printf("gtask: %p ta_flags=%x ta_priority=%d ta_func=%p ta_context=%p\n",
 113                gtask, gtask->ta_flags, gtask->ta_priority, gtask->ta_func, gtask->ta_context);
 114 }
 115 #endif
 116
 117 static __inline int
 118 TQ_SLEEP(struct gtaskqueue *tq, void *p, const char *wm)
 119 {
 120         if (tq->tq_spin)
 121                 return (msleep_spin(p, (struct mtx *)&tq->tq_mutex, wm, 0));
 122         return (msleep(p, &tq->tq_mutex, 0, wm, 0));
 123 }
 124
 125 static struct gtaskqueue *
 126 _gtaskqueue_create(const char *name, int mflags,
 127                  taskqueue_enqueue_fn enqueue, void *context,
 128                  int mtxflags, const char *mtxname __unused)
 129 {
 130         struct gtaskqueue *queue;
 131         char *tq_name;
 132
 133         tq_name = malloc(TASKQUEUE_NAMELEN, M_GTASKQUEUE, mflags | M_ZERO);
 134         if (!tq_name)
 135                 return (NULL);
 136
 137         snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
 138
 139         queue = malloc(sizeof(struct gtaskqueue), M_GTASKQUEUE, mflags | M_ZERO);
 140         if (!queue) {
 141                 free(tq_name, M_GTASKQUEUE);
 142                 return (NULL);
 143         }
 144
 145         STAILQ_INIT(&queue->tq_queue);
 146         LIST_INIT(&queue->tq_active);
 147         queue->tq_enqueue = enqueue;
 148         queue->tq_context = context;
 149         queue->tq_name = tq_name;
 150         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
 151         queue->tq_flags |= TQ_FLAGS_ACTIVE;
 152         if (enqueue == gtaskqueue_thread_enqueue)
 153                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
 154         mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
 155
 156         return (queue);
 157 }
 158
 159 /*
 160  * Signal a taskqueue thread to terminate.
 161  */
 162 static void
 163 gtaskqueue_terminate(struct thread **pp, struct gtaskqueue *tq)
 164 {
 165
 166         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
 167                 wakeup(tq);
 168                 TQ_SLEEP(tq, pp, "gtq_destroy");
 169         }
 170 }
 171
 172 static void __unused
 173 gtaskqueue_free(struct gtaskqueue *queue)
 174 {
 175
 176         TQ_LOCK(queue);
 177         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
 178         gtaskqueue_terminate(queue->tq_threads, queue);
 179         KASSERT(LIST_EMPTY(&queue->tq_active), ("Tasks still running?"));
 180         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
 181         mtx_destroy(&queue->tq_mutex);
 182         free(queue->tq_threads, M_GTASKQUEUE);
 183         free(queue->tq_name, M_GTASKQUEUE);
 184         free(queue, M_GTASKQUEUE);
 185 }
 186
 187 /*
 188  * Wait for all to complete, then prevent it from being enqueued
 189  */
 190 void
 191 grouptask_block(struct grouptask *grouptask)
 192 {
 193         struct gtaskqueue *queue = grouptask->gt_taskqueue;
 194         struct gtask *gtask = &grouptask->gt_task;
 195
 196 #ifdef INVARIANTS
 197         if (queue == NULL) {
 198                 gtask_dump(gtask);
 199                 panic("queue == NULL");
 200         }
 201 #endif
 202         TQ_LOCK(queue);
 203         gtask->ta_flags |= TASK_NOENQUEUE;
 204         gtaskqueue_drain_locked(queue, gtask);
 205         TQ_UNLOCK(queue);
 206 }
 207
 208 void
 209 grouptask_unblock(struct grouptask *grouptask)
 210 {
 211         struct gtaskqueue *queue = grouptask->gt_taskqueue;
 212         struct gtask *gtask = &grouptask->gt_task;
 213
 214 #ifdef INVARIANTS
 215         if (queue == NULL) {
 216                 gtask_dump(gtask);
 217                 panic("queue == NULL");
 218         }
 219 #endif
 220         TQ_LOCK(queue);
 221         gtask->ta_flags &= ~TASK_NOENQUEUE;
 222         TQ_UNLOCK(queue);
 223 }
 224
 225 int
 226 grouptaskqueue_enqueue(struct gtaskqueue *queue, struct gtask *gtask)
 227 {
 228 #ifdef INVARIANTS
 229         if (queue == NULL) {
 230                 gtask_dump(gtask);
 231                 panic("queue == NULL");
 232         }
 233 #endif
 234         TQ_LOCK(queue);
 235         if (gtask->ta_flags & TASK_ENQUEUED) {
 236                 TQ_UNLOCK(queue);
 237                 return (0);
 238         }
 239         if (gtask->ta_flags & TASK_NOENQUEUE) {
 240                 TQ_UNLOCK(queue);
 241                 return (EAGAIN);
 242         }
 243         STAILQ_INSERT_TAIL(&queue->tq_queue, gtask, ta_link);
 244         gtask->ta_flags |= TASK_ENQUEUED;
 245         TQ_UNLOCK(queue);
 246         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
 247                 queue->tq_enqueue(queue->tq_context);
 248         return (0);
 249 }
 250
 251 static void
 252 gtaskqueue_task_nop_fn(void *context)
 253 {
 254 }
 255
 256 /*
 257  * Block until all currently queued tasks in this taskqueue
 258  * have begun execution.  Tasks queued during execution of
 259  * this function are ignored.
 260  */
 261 static void
 262 gtaskqueue_drain_tq_queue(struct gtaskqueue *queue)
 263 {
 264         struct gtask t_barrier;
 265
 266         if (STAILQ_EMPTY(&queue->tq_queue))
 267                 return;
 268
 269         /*
 270          * Enqueue our barrier after all current tasks, but with
 271          * the highest priority so that newly queued tasks cannot
 272          * pass it.  Because of the high priority, we can not use
 273          * taskqueue_enqueue_locked directly (which drops the lock
 274          * anyway) so just insert it at tail while we have the
 275          * queue lock.
 276          */
 277         GTASK_INIT(&t_barrier, 0, USHRT_MAX, gtaskqueue_task_nop_fn, &t_barrier);
 278         STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
 279         t_barrier.ta_flags |= TASK_ENQUEUED;
 280
 281         /*
 282          * Once the barrier has executed, all previously queued tasks
 283          * have completed or are currently executing.
 284          */
 285         while (t_barrier.ta_flags & TASK_ENQUEUED)
 286                 TQ_SLEEP(queue, &t_barrier, "gtq_qdrain");
 287 }
 288
 289 /*
 290  * Block until all currently executing tasks for this taskqueue
 291  * complete.  Tasks that begin execution during the execution
 292  * of this function are ignored.
 293  */
 294 static void
 295 gtaskqueue_drain_tq_active(struct gtaskqueue *queue)
 296 {
 297         struct gtaskqueue_busy *tb;
 298         u_int seq;
 299
 300         if (LIST_EMPTY(&queue->tq_active))
 301                 return;
 302
 303         /* Block taskq_terminate().*/
 304         queue->tq_callouts++;
 305
 306         /* Wait for any active task with sequence from the past. */
 307         seq = queue->tq_seq;
 308 restart:
 309         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
 310                 if ((int)(tb->tb_seq - seq) <= 0) {
 311                         TQ_SLEEP(queue, tb->tb_running, "gtq_adrain");
 312                         goto restart;
 313                 }
 314         }
 315
 316         /* Release taskqueue_terminate(). */
 317         queue->tq_callouts--;
 318         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 319                 wakeup_one(queue->tq_threads);
 320 }
 321
 322 void
 323 gtaskqueue_block(struct gtaskqueue *queue)
 324 {
 325
 326         TQ_LOCK(queue);
 327         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 328         TQ_UNLOCK(queue);
 329 }
 330
 331 void
 332 gtaskqueue_unblock(struct gtaskqueue *queue)
 333 {
 334
 335         TQ_LOCK(queue);
 336         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 337         if (!STAILQ_EMPTY(&queue->tq_queue))
 338                 queue->tq_enqueue(queue->tq_context);
 339         TQ_UNLOCK(queue);
 340 }
 341
 342 static void
 343 gtaskqueue_run_locked(struct gtaskqueue *queue)
 344 {
 345         struct epoch_tracker et;
 346         struct gtaskqueue_busy tb;
 347         struct gtask *gtask;
 348         bool in_net_epoch;
 349
 350         KASSERT(queue != NULL, ("tq is NULL"));
 351         TQ_ASSERT_LOCKED(queue);
 352         tb.tb_running = NULL;
 353         LIST_INSERT_HEAD(&queue->tq_active, &tb, tb_link);
 354         in_net_epoch = false;
 355
 356         while ((gtask = STAILQ_FIRST(&queue->tq_queue)) != NULL) {
 357                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 358                 gtask->ta_flags &= ~TASK_ENQUEUED;
 359                 tb.tb_running = gtask;
 360                 tb.tb_seq = ++queue->tq_seq;
 361                 TQ_UNLOCK(queue);
 362
 363                 KASSERT(gtask->ta_func != NULL, ("task->ta_func is NULL"));
 364                 if (!in_net_epoch && TASK_IS_NET(gtask)) {
 365                         in_net_epoch = true;
 366                         NET_EPOCH_ENTER(et);
 367                 } else if (in_net_epoch && !TASK_IS_NET(gtask)) {
 368                         NET_EPOCH_EXIT(et);
 369                         in_net_epoch = false;
 370                 }
 371                 gtask->ta_func(gtask->ta_context);
 372
 373                 TQ_LOCK(queue);
 374                 wakeup(gtask);
 375         }
 376         if (in_net_epoch)
 377                 NET_EPOCH_EXIT(et);
 378         LIST_REMOVE(&tb, tb_link);
 379 }
 380
 381 static int
 382 task_is_running(struct gtaskqueue *queue, struct gtask *gtask)
 383 {
 384         struct gtaskqueue_busy *tb;
 385
 386         TQ_ASSERT_LOCKED(queue);
 387         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
 388                 if (tb->tb_running == gtask)
 389                         return (1);
 390         }
 391         return (0);
 392 }
 393
 394 static int
 395 gtaskqueue_cancel_locked(struct gtaskqueue *queue, struct gtask *gtask)
 396 {
 397
 398         if (gtask->ta_flags & TASK_ENQUEUED)
 399                 STAILQ_REMOVE(&queue->tq_queue, gtask, gtask, ta_link);
 400         gtask->ta_flags &= ~TASK_ENQUEUED;
 401         return (task_is_running(queue, gtask) ? EBUSY : 0);
 402 }
 403
 404 int
 405 gtaskqueue_cancel(struct gtaskqueue *queue, struct gtask *gtask)
 406 {
 407         int error;
 408
 409         TQ_LOCK(queue);
 410         error = gtaskqueue_cancel_locked(queue, gtask);
 411         TQ_UNLOCK(queue);
 412
 413         return (error);
 414 }
 415
 416 static void
 417 gtaskqueue_drain_locked(struct gtaskqueue *queue, struct gtask *gtask)
 418 {
 419         while ((gtask->ta_flags & TASK_ENQUEUED) || task_is_running(queue, gtask))
 420                 TQ_SLEEP(queue, gtask, "gtq_drain");
 421 }
 422
 423 void
 424 gtaskqueue_drain(struct gtaskqueue *queue, struct gtask *gtask)
 425 {
 426
 427         if (!queue->tq_spin)
 428                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 429
 430         TQ_LOCK(queue);
 431         gtaskqueue_drain_locked(queue, gtask);
 432         TQ_UNLOCK(queue);
 433 }
 434
 435 void
 436 gtaskqueue_drain_all(struct gtaskqueue *queue)
 437 {
 438
 439         if (!queue->tq_spin)
 440                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 441
 442         TQ_LOCK(queue);
 443         gtaskqueue_drain_tq_queue(queue);
 444         gtaskqueue_drain_tq_active(queue);
 445         TQ_UNLOCK(queue);
 446 }
 447
 448 static int
 449 _gtaskqueue_start_threads(struct gtaskqueue **tqp, int count, int pri,
 450     cpuset_t *mask, const char *name, va_list ap)
 451 {
 452         char ktname[MAXCOMLEN + 1];
 453         struct thread *td;
 454         struct gtaskqueue *tq;
 455         int i, error;
 456
 457         if (count <= 0)
 458                 return (EINVAL);
 459
 460         vsnprintf(ktname, sizeof(ktname), name, ap);
 461         tq = *tqp;
 462
 463         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_GTASKQUEUE,
 464             M_NOWAIT | M_ZERO);
 465         if (tq->tq_threads == NULL) {
 466                 printf("%s: no memory for %s threads\n", __func__, ktname);
 467                 return (ENOMEM);
 468         }
 469
 470         for (i = 0; i < count; i++) {
 471                 if (count == 1)
 472                         error = kthread_add(gtaskqueue_thread_loop, tqp, NULL,
 473                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 474                 else
 475                         error = kthread_add(gtaskqueue_thread_loop, tqp, NULL,
 476                             &tq->tq_threads[i], RFSTOPPED, 0,
 477                             "%s_%d", ktname, i);
 478                 if (error) {
 479                         /* should be ok to continue, taskqueue_free will dtrt */
 480                         printf("%s: kthread_add(%s): error %d", __func__,
 481                             ktname, error);
 482                         tq->tq_threads[i] = NULL;               /* paranoid */
 483                 } else
 484                         tq->tq_tcount++;
 485         }
 486         for (i = 0; i < count; i++) {
 487                 if (tq->tq_threads[i] == NULL)
 488                         continue;
 489                 td = tq->tq_threads[i];
 490                 if (mask) {
 491                         error = cpuset_setthread(td->td_tid, mask);
 492                         /*
 493                          * Failing to pin is rarely an actual fatal error;
 494                          * it'll just affect performance.
 495                          */
 496                         if (error)
 497                                 printf("%s: curthread=%llu: can't pin; "
 498                                     "error=%d\n",
 499                                     __func__,
 500                                     (unsigned long long) td->td_tid,
 501                                     error);
 502                 }
 503                 thread_lock(td);
 504                 sched_prio(td, pri);
 505                 sched_add(td, SRQ_BORING);
 506         }
 507
 508         return (0);
 509 }
 510
 511 static int
 512 gtaskqueue_start_threads(struct gtaskqueue **tqp, int count, int pri,
 513     const char *name, ...)
 514 {
 515         va_list ap;
 516         int error;
 517
 518         va_start(ap, name);
 519         error = _gtaskqueue_start_threads(tqp, count, pri, NULL, name, ap);
 520         va_end(ap);
 521         return (error);
 522 }
 523
 524 static inline void
 525 gtaskqueue_run_callback(struct gtaskqueue *tq,
 526     enum taskqueue_callback_type cb_type)
 527 {
 528         taskqueue_callback_fn tq_callback;
 529
 530         TQ_ASSERT_UNLOCKED(tq);
 531         tq_callback = tq->tq_callbacks[cb_type];
 532         if (tq_callback != NULL)
 533                 tq_callback(tq->tq_cb_contexts[cb_type]);
 534 }
 535
 536 static void
 537 gtaskqueue_thread_loop(void *arg)
 538 {
 539         struct gtaskqueue **tqp, *tq;
 540
 541         tqp = arg;
 542         tq = *tqp;
 543         gtaskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 544         TQ_LOCK(tq);
 545         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 546                 /* XXX ? */
 547                 gtaskqueue_run_locked(tq);
 548                 /*
 549                  * Because taskqueue_run() can drop tq_mutex, we need to
 550                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 551                  * meantime, which means we missed a wakeup.
 552                  */
 553                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 554                         break;
 555                 TQ_SLEEP(tq, tq, "-");
 556         }
 557         gtaskqueue_run_locked(tq);
 558         /*
 559          * This thread is on its way out, so just drop the lock temporarily
 560          * in order to call the shutdown callback.  This allows the callback
 561          * to look at the taskqueue, even just before it dies.
 562          */
 563         TQ_UNLOCK(tq);
 564         gtaskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 565         TQ_LOCK(tq);
 566
 567         /* rendezvous with thread that asked us to terminate */
 568         tq->tq_tcount--;
 569         wakeup_one(tq->tq_threads);
 570         TQ_UNLOCK(tq);
 571         kthread_exit();
 572 }
 573
 574 static void
 575 gtaskqueue_thread_enqueue(void *context)
 576 {
 577         struct gtaskqueue **tqp, *tq;
 578
 579         tqp = context;
 580         tq = *tqp;
 581         wakeup_any(tq);
 582 }
 583
 584 static struct gtaskqueue *
 585 gtaskqueue_create_fast(const char *name, int mflags,
 586                  taskqueue_enqueue_fn enqueue, void *context)
 587 {
 588         return _gtaskqueue_create(name, mflags, enqueue, context,
 589                         MTX_SPIN, "fast_taskqueue");
 590 }
 591
 592 struct taskqgroup_cpu {
 593         LIST_HEAD(, grouptask) tgc_tasks;
 594         struct gtaskqueue *tgc_taskq;
 595         int             tgc_cnt;
 596         int             tgc_cpu;
 597 };
 598
 599 struct taskqgroup {
 600         struct taskqgroup_cpu tqg_queue[MAXCPU];
 601         struct mtx      tqg_lock;
 602         const char *    tqg_name;
 603         int             tqg_cnt;
 604 };
 605
 606 struct taskq_bind_task {
 607         struct gtask bt_task;
 608         int     bt_cpuid;
 609 };
 610
 611 static void
 612 taskqgroup_cpu_create(struct taskqgroup *qgroup, int idx, int cpu)
 613 {
 614         struct taskqgroup_cpu *qcpu;
 615
 616         qcpu = &qgroup->tqg_queue[idx];
 617         LIST_INIT(&qcpu->tgc_tasks);
 618         qcpu->tgc_taskq = gtaskqueue_create_fast(NULL, M_WAITOK,
 619             taskqueue_thread_enqueue, &qcpu->tgc_taskq);
 620         gtaskqueue_start_threads(&qcpu->tgc_taskq, 1, PI_SOFT,
 621             "%s_%d", qgroup->tqg_name, idx);
 622         qcpu->tgc_cpu = cpu;
 623 }
 624
 625 /*
 626  * Find the taskq with least # of tasks that doesn't currently have any
 627  * other queues from the uniq identifier.
 628  */
 629 static int
 630 taskqgroup_find(struct taskqgroup *qgroup, void *uniq)
 631 {
 632         struct grouptask *n;
 633         int i, idx, mincnt;
 634         int strict;
 635
 636         mtx_assert(&qgroup->tqg_lock, MA_OWNED);
 637         KASSERT(qgroup->tqg_cnt != 0,
 638             ("qgroup %s has no queues", qgroup->tqg_name));
 639
 640         /*
 641          * Two passes: first scan for a queue with the least tasks that
 642          * does not already service this uniq id.  If that fails simply find
 643          * the queue with the least total tasks.
 644          */
 645         for (idx = -1, mincnt = INT_MAX, strict = 1; mincnt == INT_MAX;
 646             strict = 0) {
 647                 for (i = 0; i < qgroup->tqg_cnt; i++) {
 648                         if (qgroup->tqg_queue[i].tgc_cnt > mincnt)
 649                                 continue;
 650                         if (strict) {
 651                                 LIST_FOREACH(n, &qgroup->tqg_queue[i].tgc_tasks,
 652                                     gt_list)
 653                                         if (n->gt_uniq == uniq)
 654                                                 break;
 655                                 if (n != NULL)
 656                                         continue;
 657                         }
 658                         mincnt = qgroup->tqg_queue[i].tgc_cnt;
 659                         idx = i;
 660                 }
 661         }
 662         if (idx == -1)
 663                 panic("%s: failed to pick a qid.", __func__);
 664
 665         return (idx);
 666 }
 667
 668 void
 669 taskqgroup_attach(struct taskqgroup *qgroup, struct grouptask *gtask,
 670     void *uniq, device_t dev, struct resource *irq, const char *name)
 671 {
 672         int cpu, qid, error;
 673
 674         KASSERT(qgroup->tqg_cnt > 0,
 675             ("qgroup %s has no queues", qgroup->tqg_name));
 676
 677         gtask->gt_uniq = uniq;
 678         snprintf(gtask->gt_name, GROUPTASK_NAMELEN, "%s", name ? name : "grouptask");
 679         gtask->gt_dev = dev;
 680         gtask->gt_irq = irq;
 681         gtask->gt_cpu = -1;
 682         mtx_lock(&qgroup->tqg_lock);
 683         qid = taskqgroup_find(qgroup, uniq);
 684         qgroup->tqg_queue[qid].tgc_cnt++;
 685         LIST_INSERT_HEAD(&qgroup->tqg_queue[qid].tgc_tasks, gtask, gt_list);
 686         gtask->gt_taskqueue = qgroup->tqg_queue[qid].tgc_taskq;
 687         if (dev != NULL && irq != NULL) {
 688                 cpu = qgroup->tqg_queue[qid].tgc_cpu;
 689                 gtask->gt_cpu = cpu;
 690                 mtx_unlock(&qgroup->tqg_lock);
 691                 error = bus_bind_intr(dev, irq, cpu);
 692                 if (error)
 693                         printf("%s: binding interrupt failed for %s: %d\n",
 694                             __func__, gtask->gt_name, error);
 695         } else
 696                 mtx_unlock(&qgroup->tqg_lock);
 697 }
 698
 699 int
 700 taskqgroup_attach_cpu(struct taskqgroup *qgroup, struct grouptask *gtask,
 701     void *uniq, int cpu, device_t dev, struct resource *irq, const char *name)
 702 {
 703         int i, qid, error;
 704
 705         gtask->gt_uniq = uniq;
 706         snprintf(gtask->gt_name, GROUPTASK_NAMELEN, "%s", name ? name : "grouptask");
 707         gtask->gt_dev = dev;
 708         gtask->gt_irq = irq;
 709         gtask->gt_cpu = cpu;
 710         mtx_lock(&qgroup->tqg_lock);
 711         for (i = 0, qid = -1; i < qgroup->tqg_cnt; i++)
 712                 if (qgroup->tqg_queue[i].tgc_cpu == cpu) {
 713                         qid = i;
 714                         break;
 715                 }
 716         if (qid == -1) {
 717                 mtx_unlock(&qgroup->tqg_lock);
 718                 printf("%s: qid not found for %s cpu=%d\n", __func__, gtask->gt_name, cpu);
 719                 return (EINVAL);
 720         }
 721         qgroup->tqg_queue[qid].tgc_cnt++;
 722         LIST_INSERT_HEAD(&qgroup->tqg_queue[qid].tgc_tasks, gtask, gt_list);
 723         gtask->gt_taskqueue = qgroup->tqg_queue[qid].tgc_taskq;
 724         cpu = qgroup->tqg_queue[qid].tgc_cpu;
 725         mtx_unlock(&qgroup->tqg_lock);
 726
 727         if (dev != NULL && irq != NULL) {
 728                 error = bus_bind_intr(dev, irq, cpu);
 729                 if (error)
 730                         printf("%s: binding interrupt failed for %s: %d\n",
 731                             __func__, gtask->gt_name, error);
 732         }
 733         return (0);
 734 }
 735
 736 void
 737 taskqgroup_detach(struct taskqgroup *qgroup, struct grouptask *gtask)
 738 {
 739         int i;
 740
 741         grouptask_block(gtask);
 742         mtx_lock(&qgroup->tqg_lock);
 743         for (i = 0; i < qgroup->tqg_cnt; i++)
 744                 if (qgroup->tqg_queue[i].tgc_taskq == gtask->gt_taskqueue)
 745                         break;
 746         if (i == qgroup->tqg_cnt)
 747                 panic("%s: task %s not in group", __func__, gtask->gt_name);
 748         qgroup->tqg_queue[i].tgc_cnt--;
 749         LIST_REMOVE(gtask, gt_list);
 750         mtx_unlock(&qgroup->tqg_lock);
 751         gtask->gt_taskqueue = NULL;
 752         gtask->gt_task.ta_flags &= ~TASK_NOENQUEUE;
 753 }
 754
 755 static void
 756 taskqgroup_binder(void *ctx)
 757 {
 758         struct taskq_bind_task *gtask;
 759         cpuset_t mask;
 760         int error;
 761
 762         gtask = ctx;
 763         CPU_ZERO(&mask);
 764         CPU_SET(gtask->bt_cpuid, &mask);
 765         error = cpuset_setthread(curthread->td_tid, &mask);
 766         thread_lock(curthread);
 767         sched_bind(curthread, gtask->bt_cpuid);
 768         thread_unlock(curthread);
 769
 770         if (error)
 771                 printf("%s: binding curthread failed: %d\n", __func__, error);
 772         free(gtask, M_DEVBUF);
 773 }
 774
 775 void
 776 taskqgroup_bind(struct taskqgroup *qgroup)
 777 {
 778         struct taskq_bind_task *gtask;
 779         int i;
 780
 781         /*
 782          * Bind taskqueue threads to specific CPUs, if they have been assigned
 783          * one.
 784          */
 785         if (qgroup->tqg_cnt == 1)
 786                 return;
 787
 788         for (i = 0; i < qgroup->tqg_cnt; i++) {
 789                 gtask = malloc(sizeof(*gtask), M_DEVBUF, M_WAITOK);
 790                 GTASK_INIT(&gtask->bt_task, 0, 0, taskqgroup_binder, gtask);
 791                 gtask->bt_cpuid = qgroup->tqg_queue[i].tgc_cpu;
 792                 grouptaskqueue_enqueue(qgroup->tqg_queue[i].tgc_taskq,
 793                     &gtask->bt_task);
 794         }
 795 }
 796
 797 struct taskqgroup *
 798 taskqgroup_create(const char *name, int cnt, int stride)
 799 {
 800         struct taskqgroup *qgroup;
 801         int cpu, i, j;
 802
 803         qgroup = malloc(sizeof(*qgroup), M_GTASKQUEUE, M_WAITOK | M_ZERO);
 804         mtx_init(&qgroup->tqg_lock, "taskqgroup", NULL, MTX_DEF);
 805         qgroup->tqg_name = name;
 806         qgroup->tqg_cnt = cnt;
 807
 808         for (cpu = i = 0; i < cnt; i++) {
 809                 taskqgroup_cpu_create(qgroup, i, cpu);
 810                 for (j = 0; j < stride; j++)
 811                         cpu = CPU_NEXT(cpu);
 812         }
 813         return (qgroup);
 814 }
 815
 816 void
 817 taskqgroup_destroy(struct taskqgroup *qgroup)
 818 {
 819 }
 820
 821 void
 822 taskqgroup_drain_all(struct taskqgroup *tqg)
 823 {
 824         struct gtaskqueue *q;
 825
 826         for (int i = 0; i < mp_ncpus; i++) {
 827                 q = tqg->tqg_queue[i].tgc_taskq;
 828                 if (q == NULL)
 829                         continue;
 830                 gtaskqueue_drain_all(q);
 831         }
 832 }