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