thr_setschedparam.c revision 113658
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 113658 2003-04-18 05:04:16Z deischen $ 33 */ 34#include <errno.h> 35#include <sys/param.h> 36#include <pthread.h> 37#include "thr_private.h" 38 39__weak_reference(_pthread_setschedparam, pthread_setschedparam); 40 41int 42_pthread_setschedparam(pthread_t pthread, int policy, 43 const struct sched_param *param) 44{ 45 struct pthread *curthread = _get_curthread(); 46 int in_syncq; 47 int in_readyq = 0; 48 int old_prio; 49 int ret = 0; 50 51 if ((param == NULL) || (policy < SCHED_FIFO) || (policy > SCHED_RR)) { 52 /* Return an invalid argument error: */ 53 ret = EINVAL; 54 } else if ((param->sched_priority < THR_MIN_PRIORITY) || 55 (param->sched_priority > THR_MAX_PRIORITY)) { 56 /* Return an unsupported value error. */ 57 ret = ENOTSUP; 58 59 /* Find the thread in the list of active threads: */ 60 } else if ((ret = _thr_ref_add(curthread, pthread, /*include dead*/0)) 61 == 0) { 62 /* 63 * Lock the threads scheduling queue while we change 64 * its priority: 65 */ 66 THR_SCHED_LOCK(curthread, pthread); 67 in_syncq = pthread->flags & THR_FLAGS_IN_SYNCQ; 68 69 /* Set the scheduling policy: */ 70 pthread->attr.sched_policy = policy; 71 72 if (param->sched_priority == 73 THR_BASE_PRIORITY(pthread->base_priority)) 74 /* 75 * There is nothing to do; unlock the threads 76 * scheduling queue. 77 */ 78 THR_SCHED_UNLOCK(curthread, pthread); 79 else { 80 /* 81 * Remove the thread from its current priority 82 * queue before any adjustments are made to its 83 * active priority: 84 */ 85 old_prio = pthread->active_priority; 86 if ((pthread->flags & THR_FLAGS_IN_RUNQ) != 0) { 87 in_readyq = 1; 88 THR_RUNQ_REMOVE(pthread); 89 } 90 91 /* Set the thread base priority: */ 92 pthread->base_priority &= 93 (THR_SIGNAL_PRIORITY | THR_RT_PRIORITY); 94 pthread->base_priority = param->sched_priority; 95 96 /* Recalculate the active priority: */ 97 pthread->active_priority = MAX(pthread->base_priority, 98 pthread->inherited_priority); 99 100 if (in_readyq) { 101 if ((pthread->priority_mutex_count > 0) && 102 (old_prio > pthread->active_priority)) { 103 /* 104 * POSIX states that if the priority is 105 * being lowered, the thread must be 106 * inserted at the head of the queue for 107 * its priority if it owns any priority 108 * protection or inheritence mutexes. 109 */ 110 THR_RUNQ_INSERT_HEAD(pthread); 111 } 112 else 113 THR_RUNQ_INSERT_TAIL(pthread); 114 } 115 116 /* Unlock the threads scheduling queue: */ 117 THR_SCHED_UNLOCK(curthread, pthread); 118 119 /* 120 * Check for any mutex priority adjustments. This 121 * includes checking for a priority mutex on which 122 * this thread is waiting. 123 */ 124 _mutex_notify_priochange(curthread, pthread, in_syncq); 125 } 126 _thr_ref_delete(curthread, pthread); 127 } 128 return (ret); 129} 130