2 * Copyright (c) 1998 Daniel Eischen <eischen@vigrid.com>.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
35 #include <sys/queue.h>
38 #include "thr_private.h"
41 static void pq_insert_prio_list(pq_queue_t *pq, int prio);
43 #if defined(_PTHREADS_INVARIANTS)
45 #define PQ_IN_SCHEDQ (THR_FLAGS_IN_RUNQ | THR_FLAGS_IN_WAITQ)
47 #define PQ_SET_ACTIVE(pq) (pq)->pq_flags |= PQF_ACTIVE
48 #define PQ_CLEAR_ACTIVE(pq) (pq)->pq_flags &= ~PQF_ACTIVE
49 #define PQ_ASSERT_ACTIVE(pq, msg) do { \
50 if (((pq)->pq_flags & PQF_ACTIVE) == 0) \
53 #define PQ_ASSERT_INACTIVE(pq, msg) do { \
54 if (((pq)->pq_flags & PQF_ACTIVE) != 0) \
57 #define PQ_ASSERT_IN_WAITQ(thrd, msg) do { \
58 if (((thrd)->flags & THR_FLAGS_IN_WAITQ) == 0) \
61 #define PQ_ASSERT_IN_RUNQ(thrd, msg) do { \
62 if (((thrd)->flags & THR_FLAGS_IN_RUNQ) == 0) \
65 #define PQ_ASSERT_NOT_QUEUED(thrd, msg) do { \
66 if (((thrd)->flags & PQ_IN_SCHEDQ) != 0) \
72 #define PQ_SET_ACTIVE(pq)
73 #define PQ_CLEAR_ACTIVE(pq)
74 #define PQ_ASSERT_ACTIVE(pq, msg)
75 #define PQ_ASSERT_INACTIVE(pq, msg)
76 #define PQ_ASSERT_IN_WAITQ(thrd, msg)
77 #define PQ_ASSERT_IN_RUNQ(thrd, msg)
78 #define PQ_ASSERT_NOT_QUEUED(thrd, msg)
83 _pq_alloc(pq_queue_t *pq, int minprio, int maxprio)
86 int prioslots = maxprio - minprio + 1;
91 /* Create the priority queue with (maxprio - minprio + 1) slots: */
92 else if ((pq->pq_lists =
93 (pq_list_t *) malloc(sizeof(pq_list_t) * prioslots)) == NULL)
97 /* Remember the queue size: */
98 pq->pq_size = prioslots;
105 _pq_free(pq_queue_t *pq)
107 if ((pq != NULL) && (pq->pq_lists != NULL))
112 _pq_init(pq_queue_t *pq)
116 if ((pq == NULL) || (pq->pq_lists == NULL))
120 /* Initialize the queue for each priority slot: */
121 for (i = 0; i < pq->pq_size; i++) {
122 TAILQ_INIT(&pq->pq_lists[i].pl_head);
123 pq->pq_lists[i].pl_prio = i;
124 pq->pq_lists[i].pl_queued = 0;
126 /* Initialize the priority queue: */
127 TAILQ_INIT(&pq->pq_queue);
135 _pq_remove(pq_queue_t *pq, pthread_t pthread)
137 int prio = pthread->active_priority;
140 * Make some assertions when debugging is enabled:
142 PQ_ASSERT_INACTIVE(pq, "_pq_remove: pq_active");
144 PQ_ASSERT_IN_RUNQ(pthread, "_pq_remove: Not in priority queue");
147 * Remove this thread from priority list. Note that if
148 * the priority list becomes empty, it is not removed
149 * from the priority queue because another thread may be
150 * added to the priority list (resulting in a needless
151 * removal/insertion). Priority lists are only removed
152 * from the priority queue when _pq_first is called.
154 TAILQ_REMOVE(&pq->pq_lists[prio].pl_head, pthread, pqe);
156 /* This thread is now longer in the priority queue. */
157 pthread->flags &= ~THR_FLAGS_IN_RUNQ;
164 _pq_insert_head(pq_queue_t *pq, pthread_t pthread)
169 * Make some assertions when debugging is enabled:
171 PQ_ASSERT_INACTIVE(pq, "_pq_insert_head: pq_active");
173 PQ_ASSERT_NOT_QUEUED(pthread,
174 "_pq_insert_head: Already in priority queue");
176 prio = pthread->active_priority;
177 TAILQ_INSERT_HEAD(&pq->pq_lists[prio].pl_head, pthread, pqe);
178 if (pq->pq_lists[prio].pl_queued == 0)
179 /* Insert the list into the priority queue: */
180 pq_insert_prio_list(pq, prio);
182 /* Mark this thread as being in the priority queue. */
183 pthread->flags |= THR_FLAGS_IN_RUNQ;
190 _pq_insert_tail(pq_queue_t *pq, pthread_t pthread)
195 * Make some assertions when debugging is enabled:
197 PQ_ASSERT_INACTIVE(pq, "_pq_insert_tail: pq_active");
199 PQ_ASSERT_NOT_QUEUED(pthread,
200 "_pq_insert_tail: Already in priority queue");
202 prio = pthread->active_priority;
203 TAILQ_INSERT_TAIL(&pq->pq_lists[prio].pl_head, pthread, pqe);
204 if (pq->pq_lists[prio].pl_queued == 0)
205 /* Insert the list into the priority queue: */
206 pq_insert_prio_list(pq, prio);
208 /* Mark this thread as being in the priority queue. */
209 pthread->flags |= THR_FLAGS_IN_RUNQ;
216 _pq_first(pq_queue_t *pq)
219 pthread_t pthread = NULL;
222 * Make some assertions when debugging is enabled:
224 PQ_ASSERT_INACTIVE(pq, "_pq_first: pq_active");
227 while (((pql = TAILQ_FIRST(&pq->pq_queue)) != NULL) &&
229 if ((pthread = TAILQ_FIRST(&pql->pl_head)) == NULL) {
231 * The priority list is empty; remove the list
234 TAILQ_REMOVE(&pq->pq_queue, pql, pl_link);
236 /* Mark the list as not being in the queue: */
246 * Select a thread which is allowed to run by debugger, we probably
247 * should merge the function into _pq_first if that function is only
248 * used by scheduler to select a thread.
251 _pq_first_debug(pq_queue_t *pq)
253 pq_list_t *pql, *pqlnext = NULL;
254 pthread_t pthread = NULL;
257 * Make some assertions when debugging is enabled:
259 PQ_ASSERT_INACTIVE(pq, "_pq_first: pq_active");
262 for (pql = TAILQ_FIRST(&pq->pq_queue);
263 pql != NULL && pthread == NULL; pql = pqlnext) {
264 if ((pthread = TAILQ_FIRST(&pql->pl_head)) == NULL) {
266 * The priority list is empty; remove the list
269 pqlnext = TAILQ_NEXT(pql, pl_link);
270 TAILQ_REMOVE(&pq->pq_queue, pql, pl_link);
272 /* Mark the list as not being in the queue: */
276 * note there may be a suspension event during this
277 * test, If TMDF_SUSPEND is set after we tested it,
278 * we will run the thread, this seems be a problem,
279 * fortunatly, when we are being debugged, all context
280 * switch will be done by kse_switchin, that is a
281 * syscall, kse_switchin will check the flag again,
282 * the thread will be returned via upcall, so next
283 * time, UTS won't run the thread.
285 while (pthread != NULL && !DBG_CAN_RUN(pthread)) {
286 pthread = TAILQ_NEXT(pthread, pqe);
289 pqlnext = TAILQ_NEXT(pql, pl_link);
298 pq_insert_prio_list(pq_queue_t *pq, int prio)
303 * Make some assertions when debugging is enabled:
305 PQ_ASSERT_ACTIVE(pq, "pq_insert_prio_list: pq_active");
308 * The priority queue is in descending priority order. Start at
309 * the beginning of the queue and find the list before which the
310 * new list should be inserted.
312 pql = TAILQ_FIRST(&pq->pq_queue);
313 while ((pql != NULL) && (pql->pl_prio > prio))
314 pql = TAILQ_NEXT(pql, pl_link);
316 /* Insert the list: */
318 TAILQ_INSERT_TAIL(&pq->pq_queue, &pq->pq_lists[prio], pl_link);
320 TAILQ_INSERT_BEFORE(pql, &pq->pq_lists[prio], pl_link);
322 /* Mark this list as being in the queue: */
323 pq->pq_lists[prio].pl_queued = 1;