thr_setschedparam.c revision 113786
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 113786 2003-04-21 04:02:56Z 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 if ((pthread->state == PS_DEAD) || 68 (pthread->state == PS_DEADLOCK) || 69 ((pthread->flags & THR_FLAGS_EXITING) != 0)) { 70 THR_SCHED_UNLOCK(curthread, pthread); 71 _thr_ref_delete(curthread, pthread); 72 return (ESRCH); 73 } 74 in_syncq = pthread->sflags & THR_FLAGS_IN_SYNCQ; 75 76 /* Set the scheduling policy: */ 77 pthread->attr.sched_policy = policy; 78 79 if (param->sched_priority == 80 THR_BASE_PRIORITY(pthread->base_priority)) 81 /* 82 * There is nothing to do; unlock the threads 83 * scheduling queue. 84 */ 85 THR_SCHED_UNLOCK(curthread, pthread); 86 else { 87 /* 88 * Remove the thread from its current priority 89 * queue before any adjustments are made to its 90 * active priority: 91 */ 92 old_prio = pthread->active_priority; 93 if ((pthread->flags & THR_FLAGS_IN_RUNQ) != 0) { 94 in_readyq = 1; 95 THR_RUNQ_REMOVE(pthread); 96 } 97 98 /* Set the thread base priority: */ 99 pthread->base_priority &= 100 (THR_SIGNAL_PRIORITY | THR_RT_PRIORITY); 101 pthread->base_priority = param->sched_priority; 102 103 /* Recalculate the active priority: */ 104 pthread->active_priority = MAX(pthread->base_priority, 105 pthread->inherited_priority); 106 107 if (in_readyq) { 108 if ((pthread->priority_mutex_count > 0) && 109 (old_prio > pthread->active_priority)) { 110 /* 111 * POSIX states that if the priority is 112 * being lowered, the thread must be 113 * inserted at the head of the queue for 114 * its priority if it owns any priority 115 * protection or inheritence mutexes. 116 */ 117 THR_RUNQ_INSERT_HEAD(pthread); 118 } 119 else 120 THR_RUNQ_INSERT_TAIL(pthread); 121 } 122 123 /* Unlock the threads scheduling queue: */ 124 THR_SCHED_UNLOCK(curthread, pthread); 125 126 /* 127 * Check for any mutex priority adjustments. This 128 * includes checking for a priority mutex on which 129 * this thread is waiting. 130 */ 131 _mutex_notify_priochange(curthread, pthread, in_syncq); 132 } 133 _thr_ref_delete(curthread, pthread); 134 } 135 return (ret); 136} 137