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 * $FreeBSD$ 33 */ 34 #include <errno.h> 35 #include <sys/param.h> 36 #include <pthread.h> 37 #include <stdlib.h> 38 #include "thr_private.h" 39 40 __weak_reference(_pthread_getschedparam, pthread_getschedparam); 41 __weak_reference(_pthread_setschedparam, pthread_setschedparam); 42 43 int 44 _pthread_getschedparam(pthread_t pthread, int *policy, 45 struct sched_param *param) 46 { 47 if (param == NULL || policy == NULL) 48 return (EINVAL); 49 if (_find_thread(pthread) == ESRCH) 50 return (ESRCH); 51 param->sched_priority = pthread->base_priority; 52 *policy = pthread->attr.sched_policy; 53 return(0); 54 } 55 56 int 57 _pthread_setschedparam(pthread_t pthread, int policy, 58 const struct sched_param *param) 59 { 60 struct pthread_mutex *mtx; 61 int old_prio; 62 63 mtx = NULL; 64 old_prio = 0; 65 if ((param == NULL) || (policy < SCHED_FIFO) || (policy > SCHED_RR)) 66 return (EINVAL); 67 if ((param->sched_priority < PTHREAD_MIN_PRIORITY) || 68 (param->sched_priority > PTHREAD_MAX_PRIORITY)) 69 return (ENOTSUP); 70 if (_find_thread(pthread) != 0) 71 return (ESRCH); 72 73 /* 74 * If the pthread is waiting on a mutex grab it now. Doing it now 75 * even though we do not need it immediately greatly simplifies the 76 * LOR avoidance code. 77 */ 78 do { 79 PTHREAD_LOCK(pthread); 80 if ((pthread->flags & PTHREAD_FLAGS_IN_MUTEXQ) != 0) { 81 mtx = pthread->data.mutex; 82 if (_spintrylock(&mtx->lock) == EBUSY) 83 PTHREAD_UNLOCK(pthread); 84 else 85 break; 86 } else { 87 break; 88 } 89 } while (1); 90 91 PTHREAD_ASSERT(pthread->active_priority >= pthread->inherited_priority, 92 "active priority cannot be less than inherited priority"); 93 old_prio = pthread->base_priority; 94 pthread->base_priority = param->sched_priority; 95 if (param->sched_priority <= pthread->active_priority) { 96 /* 97 * Active priority is affected only if it was the 98 * base priority and the new base priority is lower. 99 */ 100 if (pthread->active_priority == old_prio && 101 pthread->active_priority != pthread->inherited_priority) { 102 pthread->active_priority = param->sched_priority; 103 readjust_priorities(pthread, mtx); 104 } 105 106 } else { 107 /* 108 * New base priority is greater than active priority. This 109 * only affects threads that are holding priority inheritance 110 * mutexes this thread is waiting on and its position in the 111 * queue. 112 */ 113 pthread->active_priority = param->sched_priority; 114 readjust_priorities(pthread, mtx); 115 116 } 117 pthread->attr.sched_policy = policy; 118 PTHREAD_UNLOCK(pthread); 119 if (mtx != NULL) 120 _SPINUNLOCK(&mtx->lock); 121 return(0); 122 } 123