xref: /freebsd/lib/libthr/thread/thr_setschedparam.c (revision 035e325c81b75ea3b5c878c55cc133672b6ac06d)
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, ret = 0;
46 #if 0
47 	int in_readyq = 0;
48 #endif
49 
50 	if ((param == NULL) || (policy < SCHED_FIFO) || (policy > SCHED_RR))
51 		return (EINVAL);
52 
53 	if ((param->sched_priority < PTHREAD_MIN_PRIORITY) ||
54 	    (param->sched_priority > PTHREAD_MAX_PRIORITY))
55 		return (ENOTSUP);
56 
57 	/* Find the thread in the list of active threads: */
58 	if ((ret = _find_thread(pthread)) == 0) {
59 		GIANT_LOCK(curthread);
60 
61 		if (param->sched_priority !=
62 		    PTHREAD_BASE_PRIORITY(pthread->base_priority)) {
63 			/*
64 			 * Remove the thread from its current priority
65 			 * queue before any adjustments are made to its
66 			 * active priority:
67 			 */
68 			old_prio = pthread->active_priority;
69 #if 0	/* XXXTHR */
70 			if ((pthread->flags & PTHREAD_FLAGS_IN_PRIOQ) != 0) {
71 				in_readyq = 1;
72 				PTHREAD_PRIOQ_REMOVE(pthread);
73 			}
74 #endif
75 
76 			/* Set the thread base priority: */
77 			pthread->base_priority &=
78 			    (PTHREAD_SIGNAL_PRIORITY | PTHREAD_RT_PRIORITY);
79 			pthread->base_priority = param->sched_priority;
80 
81 			/* Recalculate the active priority: */
82 			pthread->active_priority = MAX(pthread->base_priority,
83 			    pthread->inherited_priority);
84 #if 0
85 			if (in_readyq) {
86 				if ((pthread->priority_mutex_count > 0) &&
87 				    (old_prio > pthread->active_priority)) {
88 					/*
89 					 * POSIX states that if the priority is
90 					 * being lowered, the thread must be
91 					 * inserted at the head of the queue for
92 					 * its priority if it owns any priority
93 					 * protection or inheritence mutexes.
94 					 */
95 					PTHREAD_PRIOQ_INSERT_HEAD(pthread);
96 				}
97 				else
98 					PTHREAD_PRIOQ_INSERT_TAIL(pthread);
99 			}
100 #endif
101 
102 			/*
103 			 * Check for any mutex priority adjustments.  This
104 			 * includes checking for a priority mutex on which
105 			 * this thread is waiting.
106 			 */
107 			_mutex_notify_priochange(pthread);
108 		}
109 
110 		/* Set the scheduling policy: */
111 		pthread->attr.sched_policy = policy;
112 
113 		GIANT_UNLOCK(curthread);
114 	}
115 	return(ret);
116 }
117