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/* $OpenBSD: uthread_setschedparam.c,v 1.1 1999/05/26 00:18:25 d Exp $ */
/*
* Copyright (c) 1998 Daniel Eischen <eischen@vigrid.com>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Daniel Eischen.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <errno.h>
#include <sys/param.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
int
pthread_setschedparam(pthread_t pthread, int policy, const struct sched_param *param)
{
int old_prio, in_readyq = 0, ret = 0;
if ((param == NULL) || (param->sched_priority < PTHREAD_MIN_PRIORITY) ||
(param->sched_priority > PTHREAD_MAX_PRIORITY) ||
(policy < SCHED_FIFO) || (policy > SCHED_RR))
/* Return an invalid argument error: */
ret = EINVAL;
/* Find the thread in the list of active threads: */
else if ((ret = _find_thread(pthread)) == 0) {
/*
* Guard against being preempted by a scheduling
* signal:
*/
_thread_kern_sched_defer();
if (param->sched_priority != pthread->base_priority) {
/*
* Remove the thread from its current priority
* queue before any adjustments are made to its
* active priority:
*/
if ((pthread != _thread_run) &&
(pthread->state == PS_RUNNING)) {
in_readyq = 1;
old_prio = pthread->active_priority;
PTHREAD_PRIOQ_REMOVE(pthread);
}
/* Set the thread base priority: */
pthread->base_priority = param->sched_priority;
/* Recalculate the active priority: */
pthread->active_priority = MAX(pthread->base_priority,
pthread->inherited_priority);
if (in_readyq) {
if ((pthread->priority_mutex_count > 0) &&
(old_prio > pthread->active_priority)) {
/*
* POSIX states that if the priority is
* being lowered, the thread must be
* inserted at the head of the queue for
* its priority if it owns any priority
* protection or inheritence mutexes.
*/
PTHREAD_PRIOQ_INSERT_HEAD(pthread);
}
else
PTHREAD_PRIOQ_INSERT_TAIL(pthread);
}
/*
* Check for any mutex priority adjustments. This
* includes checking for a priority mutex on which
* this thread is waiting.
*/
_mutex_notify_priochange(pthread);
}
/* Set the scheduling policy: */
pthread->attr.sched_policy = policy;
/*
* Renable preemption and yield if a scheduling signal
* arrived while in the critical region:
*/
_thread_kern_sched_undefer();
}
return(ret);
}
#endif
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