lib/libkse/thread/thr_setschedparam.c

   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
  35 #include "namespace.h"
  36 #include <errno.h>
  37 #include <sys/param.h>
  38 #include <pthread.h>
  39 #include "un-namespace.h"
  40 #include "thr_private.h"
  41
  42 __weak_reference(_pthread_setschedparam, pthread_setschedparam);
  43
  44 int
  45 _pthread_setschedparam(pthread_t pthread, int policy,
  46         const struct sched_param *param)
  47 {
  48         struct pthread *curthread = _get_curthread();
  49         int     in_syncq;
  50         int     in_readyq = 0;
  51         int     old_prio;
  52         int     ret = 0;
  53
  54         if ((param == NULL) || (policy < SCHED_FIFO) || (policy > SCHED_RR)) {
  55                 /* Return an invalid argument error: */
  56                 ret = EINVAL;
  57         } else if ((param->sched_priority < THR_MIN_PRIORITY) ||
  58             (param->sched_priority > THR_MAX_PRIORITY)) {
  59                 /* Return an unsupported value error. */
  60                 ret = ENOTSUP;
  61
  62         /* Find the thread in the list of active threads: */
  63         } else if ((ret = _thr_ref_add(curthread, pthread, /*include dead*/0))
  64             == 0) {
  65                 /*
  66                  * Lock the threads scheduling queue while we change
  67                  * its priority:
  68                  */
  69                 THR_SCHED_LOCK(curthread, pthread);
  70                 if ((pthread->state == PS_DEAD) ||
  71                     (pthread->state == PS_DEADLOCK) ||
  72                     ((pthread->flags & THR_FLAGS_EXITING) != 0)) {
  73                         THR_SCHED_UNLOCK(curthread, pthread);
  74                         _thr_ref_delete(curthread, pthread);
  75                         return (ESRCH);
  76                 }
  77                 in_syncq = pthread->sflags & THR_FLAGS_IN_SYNCQ;
  78
  79                 /* Set the scheduling policy: */
  80                 pthread->attr.sched_policy = policy;
  81
  82                 if (param->sched_priority ==
  83                     THR_BASE_PRIORITY(pthread->base_priority))
  84                         /*
  85                          * There is nothing to do; unlock the threads
  86                          * scheduling queue.
  87                          */
  88                         THR_SCHED_UNLOCK(curthread, pthread);
  89                 else {
  90                         /*
  91                          * Remove the thread from its current priority
  92                          * queue before any adjustments are made to its
  93                          * active priority:
  94                          */
  95                         old_prio = pthread->active_priority;
  96                         if ((pthread->flags & THR_FLAGS_IN_RUNQ) != 0) {
  97                                 in_readyq = 1;
  98                                 THR_RUNQ_REMOVE(pthread);
  99                         }
 100
 101                         /* Set the thread base priority: */
 102                         pthread->base_priority &=
 103                             (THR_SIGNAL_PRIORITY | THR_RT_PRIORITY);
 104                         pthread->base_priority = param->sched_priority;
 105
 106                         /* Recalculate the active priority: */
 107                         pthread->active_priority = MAX(pthread->base_priority,
 108                             pthread->inherited_priority);
 109
 110                         if (in_readyq) {
 111                                 if ((pthread->priority_mutex_count > 0) &&
 112                                     (old_prio > pthread->active_priority)) {
 113                                         /*
 114                                          * POSIX states that if the priority is
 115                                          * being lowered, the thread must be
 116                                          * inserted at the head of the queue for
 117                                          * its priority if it owns any priority
 118                                          * protection or inheritence mutexes.
 119                                          */
 120                                         THR_RUNQ_INSERT_HEAD(pthread);
 121                                 }
 122                                 else
 123                                         THR_RUNQ_INSERT_TAIL(pthread);
 124                         }
 125
 126                         /* Unlock the threads scheduling queue: */
 127                         THR_SCHED_UNLOCK(curthread, pthread);
 128
 129                         /*
 130                          * Check for any mutex priority adjustments.  This
 131                          * includes checking for a priority mutex on which
 132                          * this thread is waiting.
 133                          */
 134                         _mutex_notify_priochange(curthread, pthread, in_syncq);
 135                 }
 136                 _thr_ref_delete(curthread, pthread);
 137         }
 138         return (ret);
 139 }