xref: /freebsd/lib/libthr/thread/thr_setschedparam.c (revision 3d11b6c8f01e1fca5936a11d6996448467851a94)
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 
35 #include "namespace.h"
36 #include <sys/param.h>
37 #include <errno.h>
38 #include <pthread.h>
39 #include "un-namespace.h"
40 
41 #include "thr_private.h"
42 
43 __weak_reference(_pthread_setschedparam, pthread_setschedparam);
44 
45 /*
46  * Set a thread's scheduling parameters, this should be done
47  * in kernel, doing it in userland is no-op.
48  */
49 int
50 _pthread_setschedparam(pthread_t pthread, int policy,
51 	const struct sched_param *param)
52 {
53 	struct pthread *curthread = _get_curthread();
54 	int	ret = 0;
55 
56 	if ((param == NULL) || (policy < SCHED_FIFO) || (policy > SCHED_RR)) {
57 		ret = EINVAL;
58 	} else if ((param->sched_priority < THR_MIN_PRIORITY) ||
59 	    (param->sched_priority > THR_MAX_PRIORITY)) {
60 		ret = ENOTSUP;
61 	} else if ((ret = _thr_ref_add(curthread, pthread, /*include dead*/0))
62 	    == 0) {
63 		/*
64 		 * Lock the threads scheduling queue while we change
65 		 * its priority:
66 		 */
67 		THR_THREAD_LOCK(curthread, pthread);
68 		if (pthread->state == PS_DEAD) {
69 			THR_THREAD_UNLOCK(curthread, pthread);
70 			_thr_ref_delete(curthread, pthread);
71 			return (ESRCH);
72 		}
73 
74 		/* Set the scheduling policy: */
75 		pthread->attr.sched_policy = policy;
76 
77 		if (param->sched_priority ==
78 		    THR_BASE_PRIORITY(pthread->base_priority))
79 			/*
80 			 * There is nothing to do; unlock the threads
81 			 * scheduling queue.
82 			 */
83 			THR_THREAD_UNLOCK(curthread, pthread);
84 		else {
85 			pthread->base_priority = param->sched_priority;
86 
87 			/* Recalculate the active priority: */
88 			pthread->active_priority = MAX(pthread->base_priority,
89 			    pthread->inherited_priority);
90 
91 			THR_THREAD_UNLOCK(curthread, pthread);
92 		}
93 		_thr_ref_delete(curthread, pthread);
94 	}
95 	return (ret);
96 }
97