xref: /freebsd/lib/libthr/thread/thr_setschedparam.c (revision 77b7cdf1999ee965ad494fddd184b18f532ac91a)
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  * $FreeBSD$
33  */
34 #include <errno.h>
35 #include <sys/param.h>
36 #include <pthread.h>
37 #include "thr_private.h"
38 
39 __weak_reference(_pthread_setschedparam, pthread_setschedparam);
40 
41 int
42 _pthread_setschedparam(pthread_t pthread, int policy,
43 	const struct sched_param *param)
44 {
45 	int old_prio, in_readyq = 0, ret = 0;
46 
47 	if ((param == NULL) || (policy < SCHED_FIFO) || (policy > SCHED_RR))
48 		return (EINVAL);
49 
50 	if ((param->sched_priority < PTHREAD_MIN_PRIORITY) ||
51 	    (param->sched_priority > PTHREAD_MAX_PRIORITY))
52 		return (ENOTSUP);
53 
54 	/* Find the thread in the list of active threads: */
55 	if ((ret = _find_thread(pthread)) == 0) {
56 		GIANT_LOCK(curthread);
57 
58 		if (param->sched_priority !=
59 		    PTHREAD_BASE_PRIORITY(pthread->base_priority)) {
60 			/*
61 			 * Remove the thread from its current priority
62 			 * queue before any adjustments are made to its
63 			 * active priority:
64 			 */
65 			old_prio = pthread->active_priority;
66 #if 0	/* XXXTHR */
67 			if ((pthread->flags & PTHREAD_FLAGS_IN_PRIOQ) != 0) {
68 				in_readyq = 1;
69 				PTHREAD_PRIOQ_REMOVE(pthread);
70 			}
71 #endif
72 
73 			/* Set the thread base priority: */
74 			pthread->base_priority &=
75 			    (PTHREAD_SIGNAL_PRIORITY | PTHREAD_RT_PRIORITY);
76 			pthread->base_priority = param->sched_priority;
77 
78 			/* Recalculate the active priority: */
79 			pthread->active_priority = MAX(pthread->base_priority,
80 			    pthread->inherited_priority);
81 #if 0
82 			if (in_readyq) {
83 				if ((pthread->priority_mutex_count > 0) &&
84 				    (old_prio > pthread->active_priority)) {
85 					/*
86 					 * POSIX states that if the priority is
87 					 * being lowered, the thread must be
88 					 * inserted at the head of the queue for
89 					 * its priority if it owns any priority
90 					 * protection or inheritence mutexes.
91 					 */
92 					PTHREAD_PRIOQ_INSERT_HEAD(pthread);
93 				}
94 				else
95 					PTHREAD_PRIOQ_INSERT_TAIL(pthread);
96 			}
97 #endif
98 
99 			/*
100 			 * Check for any mutex priority adjustments.  This
101 			 * includes checking for a priority mutex on which
102 			 * this thread is waiting.
103 			 */
104 			_mutex_notify_priochange(pthread);
105 		}
106 
107 		/* Set the scheduling policy: */
108 		pthread->attr.sched_policy = policy;
109 
110 		GIANT_UNLOCK(curthread);
111 	}
112 	return(ret);
113 }
114