thr_setschedparam.c revision 112965 
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 112965 2003-04-02 03:05:39Z jeff $
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
41int
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