thr_setschedparam.c revision 157194 
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: head/lib/libthr/thread/thr_setschedparam.c 157194 2006-03-27 23:50:21Z davidxu $
33 */
34
35#include <errno.h>
36#include <sys/param.h>
37#include <pthread.h>
38
39#include "thr_private.h"
40
41__weak_reference(_pthread_setschedparam, pthread_setschedparam);
42
43/*
44 * Set a thread's scheduling parameters, this should be done
45 * in kernel, doing it in userland is no-op.
46 */
47int
48_pthread_setschedparam(pthread_t pthread, int policy,
49	const struct sched_param *param)
50{
51	struct pthread *curthread = _get_curthread();
52	int	ret = 0;
53
54	if ((param == NULL) || (policy < SCHED_FIFO) || (policy > SCHED_RR)) {
55		ret = EINVAL;
56	} else if ((param->sched_priority < THR_MIN_PRIORITY) ||
57	    (param->sched_priority > THR_MAX_PRIORITY)) {
58		ret = ENOTSUP;
59	} else if ((ret = _thr_ref_add(curthread, pthread, /*include dead*/0))
60	    == 0) {
61		/*
62		 * Lock the threads scheduling queue while we change
63		 * its priority:
64		 */
65		THR_THREAD_LOCK(curthread, pthread);
66		if (pthread->state == PS_DEAD) {
67			THR_THREAD_UNLOCK(curthread, pthread);
68			_thr_ref_delete(curthread, pthread);
69			return (ESRCH);
70		}
71
72		/* Set the scheduling policy: */
73		pthread->attr.sched_policy = policy;
74
75		if (param->sched_priority ==
76		    THR_BASE_PRIORITY(pthread->base_priority))
77			/*
78			 * There is nothing to do; unlock the threads
79			 * scheduling queue.
80			 */
81			THR_THREAD_UNLOCK(curthread, pthread);
82		else {
83			pthread->base_priority = param->sched_priority;
84
85			/* Recalculate the active priority: */
86			pthread->active_priority = MAX(pthread->base_priority,
87			    pthread->inherited_priority);
88
89			THR_THREAD_UNLOCK(curthread, pthread);
90		}
91		_thr_ref_delete(curthread, pthread);
92	}
93	return (ret);
94}
95