0feabab576
o In the rwlock code: move a duplicated check inside an if..else to after the if...else clause. o When initializing a static rwlock move the initialization check inside the lock. o In thr_setschedparam.c: When breaking out of the trylock...retry if busy loop make sure to reset the mtx pointer to null if the mutex is nolonger in a queue.
124 lines
4.1 KiB
C
124 lines
4.1 KiB
C
/*
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* Copyright (c) 1998 Daniel Eischen <eischen@vigrid.com>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Daniel Eischen.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <errno.h>
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#include <sys/param.h>
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#include <pthread.h>
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#include <stdlib.h>
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#include "thr_private.h"
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__weak_reference(_pthread_getschedparam, pthread_getschedparam);
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__weak_reference(_pthread_setschedparam, pthread_setschedparam);
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int
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_pthread_getschedparam(pthread_t pthread, int *policy,
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struct sched_param *param)
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{
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if (param == NULL || policy == NULL)
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return (EINVAL);
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if (_find_thread(pthread) == ESRCH)
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return (ESRCH);
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param->sched_priority = pthread->base_priority;
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*policy = pthread->attr.sched_policy;
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return(0);
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}
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int
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_pthread_setschedparam(pthread_t pthread, int policy,
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const struct sched_param *param)
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{
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struct pthread_mutex *mtx;
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int old_prio;
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mtx = NULL;
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old_prio = 0;
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if ((param == NULL) || (policy < SCHED_FIFO) || (policy > SCHED_RR))
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return (EINVAL);
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if ((param->sched_priority < PTHREAD_MIN_PRIORITY) ||
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(param->sched_priority > PTHREAD_MAX_PRIORITY))
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return (ENOTSUP);
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if (_find_thread(pthread) != 0)
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return (ESRCH);
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/*
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* If the pthread is waiting on a mutex grab it now. Doing it now
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* even though we do not need it immediately greatly simplifies the
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* LOR avoidance code.
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*/
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do {
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PTHREAD_LOCK(pthread);
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if ((pthread->flags & PTHREAD_FLAGS_IN_MUTEXQ) != 0) {
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mtx = pthread->data.mutex;
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if (_spintrylock(&mtx->lock) == EBUSY)
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PTHREAD_UNLOCK(pthread);
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else
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break;
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} else {
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mtx = NULL;
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break;
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}
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} while (1);
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PTHREAD_ASSERT(pthread->active_priority >= pthread->inherited_priority,
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"active priority cannot be less than inherited priority");
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old_prio = pthread->base_priority;
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pthread->base_priority = param->sched_priority;
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if (param->sched_priority <= pthread->active_priority) {
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/*
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* Active priority is affected only if it was the
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* base priority and the new base priority is lower.
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*/
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if (pthread->active_priority == old_prio &&
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pthread->active_priority != pthread->inherited_priority) {
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pthread->active_priority = param->sched_priority;
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readjust_priorities(pthread, mtx);
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}
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} else {
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/*
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* New base priority is greater than active priority. This
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* only affects threads that are holding priority inheritance
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* mutexes this thread is waiting on and its position in the
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* queue.
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*/
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pthread->active_priority = param->sched_priority;
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readjust_priorities(pthread, mtx);
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}
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pthread->attr.sched_policy = policy;
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PTHREAD_UNLOCK(pthread);
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if (mtx != NULL)
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_SPINUNLOCK(&mtx->lock);
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return(0);
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}
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