thr_setschedparam.c revision 53812
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/libkse/thread/thr_setschedparam.c 53812 1999-11-28 05:38:13Z alfred $ 33 */ 34#include <errno.h> 35#include <sys/param.h> 36#ifdef _THREAD_SAFE 37#include <pthread.h> 38#include "pthread_private.h" 39 40int 41pthread_setschedparam(pthread_t pthread, int policy, 42 const struct sched_param *param) 43{ 44 int old_prio, in_readyq = 0, ret = 0; 45 46 if ((param == NULL) || (param->sched_priority < PTHREAD_MIN_PRIORITY) || 47 (param->sched_priority > PTHREAD_MAX_PRIORITY) || 48 (policy < SCHED_FIFO) || (policy > SCHED_RR)) 49 /* Return an invalid argument error: */ 50 ret = EINVAL; 51 52 /* Find the thread in the list of active threads: */ 53 else if ((ret = _find_thread(pthread)) == 0) { 54 /* 55 * Defer signals to protect the scheduling queues from 56 * access by the signal handler: 57 */ 58 _thread_kern_sig_defer(); 59 60 if (param->sched_priority != pthread->base_priority) { 61 /* 62 * Remove the thread from its current priority 63 * queue before any adjustments are made to its 64 * active priority: 65 */ 66 if ((pthread->flags & PTHREAD_FLAGS_IN_PRIOQ) != 0) { 67 in_readyq = 1; 68 old_prio = pthread->active_priority; 69 PTHREAD_PRIOQ_REMOVE(pthread); 70 } 71 72 /* Set the thread base priority: */ 73 pthread->base_priority = param->sched_priority; 74 75 /* Recalculate the active priority: */ 76 pthread->active_priority = MAX(pthread->base_priority, 77 pthread->inherited_priority); 78 79 if (in_readyq) { 80 if ((pthread->priority_mutex_count > 0) && 81 (old_prio > pthread->active_priority)) { 82 /* 83 * POSIX states that if the priority is 84 * being lowered, the thread must be 85 * inserted at the head of the queue for 86 * its priority if it owns any priority 87 * protection or inheritence mutexes. 88 */ 89 PTHREAD_PRIOQ_INSERT_HEAD(pthread); 90 } 91 else 92 PTHREAD_PRIOQ_INSERT_TAIL(pthread); 93 } 94 95 /* 96 * Check for any mutex priority adjustments. This 97 * includes checking for a priority mutex on which 98 * this thread is waiting. 99 */ 100 _mutex_notify_priochange(pthread); 101 } 102 103 /* Set the scheduling policy: */ 104 pthread->attr.sched_policy = policy; 105 106 /* 107 * Undefer and handle pending signals, yielding if 108 * necessary: 109 */ 110 _thread_kern_sig_undefer(); 111 } 112 return(ret); 113} 114#endif 115