lib/libc_r/uthread/uthread_priority_queue.c

   1 /*
   2  * Copyright (c) 1998 Daniel Eischen <eischen@vigrid.com>.
   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  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by Daniel Eischen.
  16  * 4. Neither the name of the author nor the names of any co-contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * $FreeBSD: src/lib/libc_r/uthread/uthread_priority_queue.c,v 1.5.2.3 2002/10/22 14:44:03 fjoe Exp $
  33  * $DragonFly: src/lib/libc_r/uthread/uthread_priority_queue.c,v 1.2 2003/06/17 06:26:48 dillon Exp $
  34  */
  35 #include <stdlib.h>
  36 #include <sys/queue.h>
  37 #include <string.h>
  38 #include <pthread.h>
  39 #include "pthread_private.h"
  40
  41 /* Prototypes: */
  42 static void pq_insert_prio_list(pq_queue_t *pq, int prio);
  43
  44 #if defined(_PTHREADS_INVARIANTS)
  45
  46 static int _pq_active = 0;
  47
  48 #define _PQ_IN_SCHEDQ   (PTHREAD_FLAGS_IN_PRIOQ | PTHREAD_FLAGS_IN_WAITQ | PTHREAD_FLAGS_IN_WORKQ)
  49
  50 #define _PQ_SET_ACTIVE()                _pq_active = 1
  51 #define _PQ_CLEAR_ACTIVE()              _pq_active = 0
  52 #define _PQ_ASSERT_ACTIVE(msg)          do {            \
  53         if (_pq_active == 0)                            \
  54                 PANIC(msg);                             \
  55 } while (0)
  56 #define _PQ_ASSERT_INACTIVE(msg)        do {            \
  57         if (_pq_active != 0)                            \
  58                 PANIC(msg);                             \
  59 } while (0)
  60 #define _PQ_ASSERT_IN_WAITQ(thrd, msg)  do {            \
  61         if (((thrd)->flags & PTHREAD_FLAGS_IN_WAITQ) == 0) \
  62                 PANIC(msg);                             \
  63 } while (0)
  64 #define _PQ_ASSERT_IN_PRIOQ(thrd, msg)  do {            \
  65         if (((thrd)->flags & PTHREAD_FLAGS_IN_PRIOQ) == 0) \
  66                 PANIC(msg);                             \
  67 } while (0)
  68 #define _PQ_ASSERT_NOT_QUEUED(thrd, msg) do {           \
  69         if (((thrd)->flags & _PQ_IN_SCHEDQ) != 0)       \
  70                 PANIC(msg);                             \
  71 } while (0)
  72 #define _PQ_ASSERT_PROTECTED(msg)                       \
  73         PTHREAD_ASSERT((_thread_kern_in_sched != 0) ||  \
  74             ((_get_curthread())->sig_defer_count > 0) ||\
  75             (_sig_in_handler != 0), msg);
  76
  77 #else
  78
  79 #define _PQ_SET_ACTIVE()
  80 #define _PQ_CLEAR_ACTIVE()
  81 #define _PQ_ASSERT_ACTIVE(msg)
  82 #define _PQ_ASSERT_INACTIVE(msg)
  83 #define _PQ_ASSERT_IN_WAITQ(thrd, msg)
  84 #define _PQ_ASSERT_IN_PRIOQ(thrd, msg)
  85 #define _PQ_ASSERT_NOT_QUEUED(thrd, msg)
  86 #define _PQ_ASSERT_PROTECTED(msg)
  87
  88 #endif
  89
  90 int
  91 _pq_alloc(pq_queue_t *pq, int minprio, int maxprio)
  92 {
  93         int ret = 0;
  94         int prioslots = maxprio - minprio + 1;
  95
  96         if (pq == NULL)
  97                 ret = -1;
  98
  99         /* Create the priority queue with (maxprio - minprio + 1) slots: */
 100         else if ((pq->pq_lists =
 101             (pq_list_t *) malloc(sizeof(pq_list_t) * prioslots)) == NULL)
 102                 ret = -1;
 103
 104         else {
 105                 /* Remember the queue size: */
 106                 pq->pq_size = prioslots;
 107                 ret = _pq_init(pq);
 108         }
 109         return (ret);
 110 }
 111
 112 int
 113 _pq_init(pq_queue_t *pq)
 114 {
 115         int i, ret = 0;
 116
 117         if ((pq == NULL) || (pq->pq_lists == NULL))
 118                 ret = -1;
 119
 120         else {
 121                 /* Initialize the queue for each priority slot: */
 122                 for (i = 0; i < pq->pq_size; i++) {
 123                         TAILQ_INIT(&pq->pq_lists[i].pl_head);
 124                         pq->pq_lists[i].pl_prio = i;
 125                         pq->pq_lists[i].pl_queued = 0;
 126                 }
 127
 128                 /* Initialize the priority queue: */
 129                 TAILQ_INIT(&pq->pq_queue);
 130                 _PQ_CLEAR_ACTIVE();
 131         }
 132         return (ret);
 133 }
 134
 135 void
 136 _pq_remove(pq_queue_t *pq, pthread_t pthread)
 137 {
 138         int prio = pthread->active_priority;
 139
 140         /*
 141          * Make some assertions when debugging is enabled:
 142          */
 143         _PQ_ASSERT_INACTIVE("_pq_remove: pq_active");
 144         _PQ_SET_ACTIVE();
 145         _PQ_ASSERT_IN_PRIOQ(pthread, "_pq_remove: Not in priority queue");
 146         _PQ_ASSERT_PROTECTED("_pq_remove: prioq not protected!");
 147
 148         /*
 149          * Remove this thread from priority list.  Note that if
 150          * the priority list becomes empty, it is not removed
 151          * from the priority queue because another thread may be
 152          * added to the priority list (resulting in a needless
 153          * removal/insertion).  Priority lists are only removed
 154          * from the priority queue when _pq_first is called.
 155          */
 156         TAILQ_REMOVE(&pq->pq_lists[prio].pl_head, pthread, pqe);
 157
 158         /* This thread is now longer in the priority queue. */
 159         pthread->flags &= ~PTHREAD_FLAGS_IN_PRIOQ;
 160
 161         _PQ_CLEAR_ACTIVE();
 162 }
 163
 164
 165 void
 166 _pq_insert_head(pq_queue_t *pq, pthread_t pthread)
 167 {
 168         int prio;
 169
 170         /*
 171          * Don't insert suspended threads into the priority queue.
 172          * The caller is responsible for setting the threads state.
 173          */
 174         if ((pthread->flags & PTHREAD_FLAGS_SUSPENDED) != 0) {
 175                 /* Make sure the threads state is suspended. */
 176                 if (pthread->state != PS_SUSPENDED)
 177                         PTHREAD_SET_STATE(pthread, PS_SUSPENDED);
 178         } else {
 179                 /*
 180                  * Make some assertions when debugging is enabled:
 181                  */
 182                 _PQ_ASSERT_INACTIVE("_pq_insert_head: pq_active");
 183                 _PQ_SET_ACTIVE();
 184                 _PQ_ASSERT_NOT_QUEUED(pthread,
 185                     "_pq_insert_head: Already in priority queue");
 186                 _PQ_ASSERT_PROTECTED("_pq_insert_head: prioq not protected!");
 187
 188                 prio = pthread->active_priority;
 189                 TAILQ_INSERT_HEAD(&pq->pq_lists[prio].pl_head, pthread, pqe);
 190                 if (pq->pq_lists[prio].pl_queued == 0)
 191                         /* Insert the list into the priority queue: */
 192                         pq_insert_prio_list(pq, prio);
 193
 194                 /* Mark this thread as being in the priority queue. */
 195                 pthread->flags |= PTHREAD_FLAGS_IN_PRIOQ;
 196
 197                 _PQ_CLEAR_ACTIVE();
 198         }
 199 }
 200
 201
 202 void
 203 _pq_insert_tail(pq_queue_t *pq, pthread_t pthread)
 204 {
 205         int prio;
 206
 207         /*
 208          * Don't insert suspended threads into the priority queue.
 209          * The caller is responsible for setting the threads state.
 210          */
 211         if ((pthread->flags & PTHREAD_FLAGS_SUSPENDED) != 0) {
 212                 /* Make sure the threads state is suspended. */
 213                 if (pthread->state != PS_SUSPENDED)
 214                         PTHREAD_SET_STATE(pthread, PS_SUSPENDED);
 215         } else {
 216                 /*
 217                  * Make some assertions when debugging is enabled:
 218                  */
 219                 _PQ_ASSERT_INACTIVE("_pq_insert_tail: pq_active");
 220                 _PQ_SET_ACTIVE();
 221                 _PQ_ASSERT_NOT_QUEUED(pthread,
 222                     "_pq_insert_tail: Already in priority queue");
 223                 _PQ_ASSERT_PROTECTED("_pq_insert_tail: prioq not protected!");
 224
 225                 prio = pthread->active_priority;
 226                 TAILQ_INSERT_TAIL(&pq->pq_lists[prio].pl_head, pthread, pqe);
 227                 if (pq->pq_lists[prio].pl_queued == 0)
 228                         /* Insert the list into the priority queue: */
 229                         pq_insert_prio_list(pq, prio);
 230
 231                 /* Mark this thread as being in the priority queue. */
 232                 pthread->flags |= PTHREAD_FLAGS_IN_PRIOQ;
 233
 234                 _PQ_CLEAR_ACTIVE();
 235         }
 236 }
 237
 238
 239 pthread_t
 240 _pq_first(pq_queue_t *pq)
 241 {
 242         pq_list_t *pql;
 243         pthread_t pthread = NULL;
 244
 245         /*
 246          * Make some assertions when debugging is enabled:
 247          */
 248         _PQ_ASSERT_INACTIVE("_pq_first: pq_active");
 249         _PQ_SET_ACTIVE();
 250         _PQ_ASSERT_PROTECTED("_pq_first: prioq not protected!");
 251
 252         while (((pql = TAILQ_FIRST(&pq->pq_queue)) != NULL) &&
 253             (pthread == NULL)) {
 254                 if ((pthread = TAILQ_FIRST(&pql->pl_head)) == NULL) {
 255                         /*
 256                          * The priority list is empty; remove the list
 257                          * from the queue.
 258                          */
 259                         TAILQ_REMOVE(&pq->pq_queue, pql, pl_link);
 260
 261                         /* Mark the list as not being in the queue: */
 262                         pql->pl_queued = 0;
 263                 } else if ((pthread->flags & PTHREAD_FLAGS_SUSPENDED) != 0) {
 264                         /*
 265                          * This thread is suspended; remove it from the
 266                          * list and ensure its state is suspended.
 267                          */
 268                         TAILQ_REMOVE(&pql->pl_head, pthread, pqe);
 269                         PTHREAD_SET_STATE(pthread, PS_SUSPENDED);
 270
 271                         /* This thread is now longer in the priority queue. */
 272                         pthread->flags &= ~PTHREAD_FLAGS_IN_PRIOQ;
 273                         pthread = NULL;
 274                 }
 275         }
 276
 277         _PQ_CLEAR_ACTIVE();
 278         return (pthread);
 279 }
 280
 281
 282 static void
 283 pq_insert_prio_list(pq_queue_t *pq, int prio)
 284 {
 285         pq_list_t *pql;
 286
 287         /*
 288          * Make some assertions when debugging is enabled:
 289          */
 290         _PQ_ASSERT_ACTIVE("pq_insert_prio_list: pq_active");
 291         _PQ_ASSERT_PROTECTED("_pq_insert_prio_list: prioq not protected!");
 292
 293         /*
 294          * The priority queue is in descending priority order.  Start at
 295          * the beginning of the queue and find the list before which the
 296          * new list should be inserted.
 297          */
 298         pql = TAILQ_FIRST(&pq->pq_queue);
 299         while ((pql != NULL) && (pql->pl_prio > prio))
 300                 pql = TAILQ_NEXT(pql, pl_link);
 301
 302         /* Insert the list: */
 303         if (pql == NULL)
 304                 TAILQ_INSERT_TAIL(&pq->pq_queue, &pq->pq_lists[prio], pl_link);
 305         else
 306                 TAILQ_INSERT_BEFORE(pql, &pq->pq_lists[prio], pl_link);
 307
 308         /* Mark this list as being in the queue: */
 309         pq->pq_lists[prio].pl_queued = 1;
 310 }
 311
 312 void
 313 _waitq_insert(pthread_t pthread)
 314 {
 315         pthread_t       tid;
 316
 317         /*
 318          * Make some assertions when debugging is enabled:
 319          */
 320         _PQ_ASSERT_INACTIVE("_waitq_insert: pq_active");
 321         _PQ_SET_ACTIVE();
 322         _PQ_ASSERT_NOT_QUEUED(pthread, "_waitq_insert: Already in queue");
 323
 324         if (pthread->wakeup_time.tv_sec == -1)
 325                 TAILQ_INSERT_TAIL(&_waitingq, pthread, pqe);
 326         else {
 327                 tid = TAILQ_FIRST(&_waitingq);
 328                 while ((tid != NULL) && (tid->wakeup_time.tv_sec != -1) &&
 329                     ((tid->wakeup_time.tv_sec < pthread->wakeup_time.tv_sec) ||
 330                     ((tid->wakeup_time.tv_sec == pthread->wakeup_time.tv_sec) &&
 331                     (tid->wakeup_time.tv_nsec <= pthread->wakeup_time.tv_nsec))))
 332                         tid = TAILQ_NEXT(tid, pqe);
 333                 if (tid == NULL)
 334                         TAILQ_INSERT_TAIL(&_waitingq, pthread, pqe);
 335                 else
 336                         TAILQ_INSERT_BEFORE(tid, pthread, pqe);
 337         }
 338         pthread->flags |= PTHREAD_FLAGS_IN_WAITQ;
 339
 340         _PQ_CLEAR_ACTIVE();
 341 }
 342
 343 void
 344 _waitq_remove(pthread_t pthread)
 345 {
 346         /*
 347          * Make some assertions when debugging is enabled:
 348          */
 349         _PQ_ASSERT_INACTIVE("_waitq_remove: pq_active");
 350         _PQ_SET_ACTIVE();
 351         _PQ_ASSERT_IN_WAITQ(pthread, "_waitq_remove: Not in queue");
 352
 353         TAILQ_REMOVE(&_waitingq, pthread, pqe);
 354         pthread->flags &= ~PTHREAD_FLAGS_IN_WAITQ;
 355
 356         _PQ_CLEAR_ACTIVE();
 357 }
 358
 359 void
 360 _waitq_setactive(void)
 361 {
 362         _PQ_ASSERT_INACTIVE("_waitq_setactive: pq_active");
 363         _PQ_SET_ACTIVE();
 364 }
 365
 366 void
 367 _waitq_clearactive(void)
 368 {
 369         _PQ_ASSERT_ACTIVE("_waitq_clearactive: ! pq_active");
 370         _PQ_CLEAR_ACTIVE();
 371 }