1 /* $OpenBSD: uthread_setschedparam.c,v 1.5 2002/01/19 23:49:32 fgsch Exp $ */
2 /*
3 * Copyright (c) 1998 Daniel Eischen <eischen@vigrid.com>.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by Daniel Eischen.
17 * 4. Neither the name of the author nor the names of any co-contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $FreeBSD: uthread_setschedparam.c,v 1.3 1999/08/28 00:03:47 peter Exp $
34 */
35 #include <errno.h>
36 #include <sys/param.h>
37 #ifdef _THREAD_SAFE
38 #include <pthread.h>
39 #include "pthread_private.h"
40
41 int
pthread_setschedparam(pthread_t pthread,int policy,const struct sched_param * param)42 pthread_setschedparam(pthread_t pthread, int policy, const struct sched_param *param)
43 {
44 int old_prio, in_readyq = 0, ret = 0;
45
46 if ((param == NULL) || (policy < SCHED_FIFO) || (policy > SCHED_RR)) {
47 /* Return an invalid argument error: */
48 ret = EINVAL;
49 } else if ((param->sched_priority < PTHREAD_MIN_PRIORITY) ||
50 (param->sched_priority > PTHREAD_MAX_PRIORITY)) {
51 /* Return an unsupported value error. */
52 ret = ENOTSUP;
53
54 /* Find the thread in the list of active threads: */
55 } else if ((ret = _find_thread(pthread)) == 0) {
56 /*
57 * Defer signals to protect the scheduling queues from
58 * access by the signal handler:
59 */
60 _thread_kern_sig_defer();
61
62 if (param->sched_priority !=
63 PTHREAD_BASE_PRIORITY(pthread->base_priority)) {
64 /*
65 * Remove the thread from its current priority
66 * queue before any adjustments are made to its
67 * active priority:
68 */
69 old_prio = pthread->active_priority;
70 if ((pthread->flags & PTHREAD_FLAGS_IN_PRIOQ) != 0) {
71 in_readyq = 1;
72 PTHREAD_PRIOQ_REMOVE(pthread);
73 }
74
75 /* Set the thread base priority: */
76 pthread->base_priority &=
77 (PTHREAD_SIGNAL_PRIORITY | PTHREAD_RT_PRIORITY);
78 pthread->base_priority = param->sched_priority;
79
80 /* Recalculate the active priority: */
81 pthread->active_priority = MAX(pthread->base_priority,
82 pthread->inherited_priority);
83
84 if (in_readyq) {
85 if ((pthread->priority_mutex_count > 0) &&
86 (old_prio > pthread->active_priority)) {
87 /*
88 * POSIX states that if the priority is
89 * being lowered, the thread must be
90 * inserted at the head of the queue for
91 * its priority if it owns any priority
92 * protection or inheritence mutexes.
93 */
94 PTHREAD_PRIOQ_INSERT_HEAD(pthread);
95 }
96 else
97 PTHREAD_PRIOQ_INSERT_TAIL(pthread);
98 }
99
100 /*
101 * Check for any mutex priority adjustments. This
102 * includes checking for a priority mutex on which
103 * this thread is waiting.
104 */
105 _mutex_notify_priochange(pthread);
106 }
107
108 /* Set the scheduling policy: */
109 pthread->attr.sched_policy = policy;
110
111 /*
112 * Undefer and handle pending signals, yielding if
113 * necessary:
114 */
115 _thread_kern_sig_undefer();
116 }
117 return(ret);
118 }
119 #endif
120