thr_setschedparam.c revision 44963
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 */ 33#include <errno.h> 34#include <sys/param.h> 35#ifdef _THREAD_SAFE 36#include <pthread.h> 37#include "pthread_private.h" 38 39int 40pthread_setschedparam(pthread_t pthread, int policy, struct sched_param *param) 41{ 42 int old_prio, in_readyq = 0, ret = 0; 43 44 if ((param == NULL) || (param->sched_priority < PTHREAD_MIN_PRIORITY) || 45 (param->sched_priority > PTHREAD_MAX_PRIORITY) || 46 (policy < SCHED_FIFO) || (policy > SCHED_RR)) 47 /* Return an invalid argument error: */ 48 ret = EINVAL; 49 50 /* Find the thread in the list of active threads: */ 51 else if ((ret = _find_thread(pthread)) == 0) { 52 /* 53 * Guard against being preempted by a scheduling 54 * signal: 55 */ 56 _thread_kern_sched_defer(); 57 58 if (param->sched_priority != pthread->base_priority) { 59 /* 60 * Remove the thread from its current priority 61 * queue before any adjustments are made to its 62 * active priority: 63 */ 64 if ((pthread != _thread_run) && 65 (pthread->state == PS_RUNNING)) { 66 in_readyq = 1; 67 old_prio = pthread->active_priority; 68 PTHREAD_PRIOQ_REMOVE(pthread); 69 } 70 71 /* Set the thread base priority: */ 72 pthread->base_priority = param->sched_priority; 73 74 /* Recalculate the active priority: */ 75 pthread->active_priority = MAX(pthread->base_priority, 76 pthread->inherited_priority); 77 78 if (in_readyq) { 79 if ((pthread->priority_mutex_count > 0) && 80 (old_prio > pthread->active_priority)) { 81 /* 82 * POSIX states that if the priority is 83 * being lowered, the thread must be 84 * inserted at the head of the queue for 85 * its priority if it owns any priority 86 * protection or inheritence mutexes. 87 */ 88 PTHREAD_PRIOQ_INSERT_HEAD(pthread); 89 } 90 else 91 PTHREAD_PRIOQ_INSERT_TAIL(pthread); 92 } 93 94 /* 95 * Check for any mutex priority adjustments. This 96 * includes checking for a priority mutex on which 97 * this thread is waiting. 98 */ 99 _mutex_notify_priochange(pthread); 100 } 101 102 /* Set the scheduling policy: */ 103 pthread->attr.sched_policy = policy; 104 105 /* 106 * Renable preemption and yield if a scheduling signal 107 * arrived while in the critical region: 108 */ 109 _thread_kern_sched_undefer(); 110 } 111 return(ret); 112} 113#endif 114