thr_setschedparam.c revision 71581
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 71581 2001-01-24 13:03:38Z deischen $ 33 */ 34#include <errno.h> 35#include <sys/param.h> 36#include <pthread.h> 37#include "pthread_private.h" 38 39#pragma weak 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 an invalid argument error: */ 49 ret = EINVAL; 50 } else if ((param->sched_priority < PTHREAD_MIN_PRIORITY) || 51 (param->sched_priority > PTHREAD_MAX_PRIORITY)) { 52 /* Return an unsupported value error. */ 53 ret = ENOTSUP; 54 55 /* Find the thread in the list of active threads: */ 56 } else if ((ret = _find_thread(pthread)) == 0) { 57 /* 58 * Defer signals to protect the scheduling queues from 59 * access by the signal handler: 60 */ 61 _thread_kern_sig_defer(); 62 63 if (param->sched_priority != 64 PTHREAD_BASE_PRIORITY(pthread->base_priority)) { 65 /* 66 * Remove the thread from its current priority 67 * queue before any adjustments are made to its 68 * active priority: 69 */ 70 old_prio = pthread->active_priority; 71 if ((pthread->flags & PTHREAD_FLAGS_IN_PRIOQ) != 0) { 72 in_readyq = 1; 73 PTHREAD_PRIOQ_REMOVE(pthread); 74 } 75 76 /* Set the thread base priority: */ 77 pthread->base_priority &= 78 (PTHREAD_SIGNAL_PRIORITY | PTHREAD_RT_PRIORITY); 79 pthread->base_priority = param->sched_priority; 80 81 /* Recalculate the active priority: */ 82 pthread->active_priority = MAX(pthread->base_priority, 83 pthread->inherited_priority); 84 85 if (in_readyq) { 86 if ((pthread->priority_mutex_count > 0) && 87 (old_prio > pthread->active_priority)) { 88 /* 89 * POSIX states that if the priority is 90 * being lowered, the thread must be 91 * inserted at the head of the queue for 92 * its priority if it owns any priority 93 * protection or inheritence mutexes. 94 */ 95 PTHREAD_PRIOQ_INSERT_HEAD(pthread); 96 } 97 else 98 PTHREAD_PRIOQ_INSERT_TAIL(pthread); 99 } 100 101 /* 102 * Check for any mutex priority adjustments. This 103 * includes checking for a priority mutex on which 104 * this thread is waiting. 105 */ 106 _mutex_notify_priochange(pthread); 107 } 108 109 /* Set the scheduling policy: */ 110 pthread->attr.sched_policy = policy; 111 112 /* 113 * Undefer and handle pending signals, yielding if 114 * necessary: 115 */ 116 _thread_kern_sig_undefer(); 117 } 118 return(ret); 119} 120