xref: /freebsd/lib/libthr/thread/thr_setschedparam.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*-
2  * SPDX-License-Identifier: BSD-4-Clause
3  *
4  * Copyright (c) 1998 Daniel Eischen <eischen@vigrid.com>.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by Daniel Eischen.
18  * 4. Neither the name of the author nor the names of any co-contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/cdefs.h>
36 #include "namespace.h"
37 #include <sys/param.h>
38 #include <errno.h>
39 #include <pthread.h>
40 #include "un-namespace.h"
41 
42 #include "thr_private.h"
43 
44 __weak_reference(_pthread_setschedparam, pthread_setschedparam);
45 
46 /*
47  * Set a thread's scheduling parameters, this should be done
48  * in kernel, doing it in userland is no-op.
49  */
50 int
51 _pthread_setschedparam(pthread_t pthread, int policy,
52 	const struct sched_param *param)
53 {
54 	struct pthread	*curthread = _get_curthread();
55 	int	ret;
56 
57 	if (pthread == curthread)
58 		THR_LOCK(curthread);
59 	else if ((ret = _thr_find_thread(curthread, pthread,
60 		 /*include dead*/0)) != 0)
61 		return (ret);
62 	if (pthread->attr.sched_policy == policy &&
63 	    (policy == SCHED_OTHER ||
64 	     pthread->attr.prio == param->sched_priority)) {
65 		pthread->attr.prio = param->sched_priority;
66 		THR_THREAD_UNLOCK(curthread, pthread);
67 		return (0);
68 	}
69 	ret = _thr_setscheduler(pthread->tid, policy, param);
70 	if (ret == -1)
71 		ret = errno;
72 	else {
73 		pthread->attr.sched_policy = policy;
74 		pthread->attr.prio = param->sched_priority;
75 	}
76 	THR_THREAD_UNLOCK(curthread, pthread);
77 	return (ret);
78 }
79