lib/libc/sys/sched.c

   1 /*      $NetBSD: sched.c,v 1.4 2012/03/18 02:04:39 christos Exp $       */
   2
   3 /*
   4  * Copyright (c) 2008, Mindaugas Rasiukevicius <rmind at NetBSD org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __RCSID("$NetBSD: sched.c,v 1.4 2012/03/18 02:04:39 christos Exp $");
  31
  32 #include <string.h>
  33 #include <unistd.h>
  34 #include <errno.h>
  35 #include <sched.h>
  36 #include <signal.h>
  37 #include <sys/param.h>
  38 #include <sys/types.h>
  39
  40 /* All LWPs in the process */
  41 #define P_ALL_LWPS              0
  42
  43 /*
  44  * Scheduling parameters.
  45  */
  46
  47 int
  48 sched_setparam(pid_t pid, const struct sched_param *param)
  49 {
  50         struct sched_param sp;
  51
  52         memset(&sp, 0, sizeof(struct sched_param));
  53         sp.sched_priority = param->sched_priority;
  54         return _sched_setparam(pid, P_ALL_LWPS, SCHED_NONE, &sp);
  55 }
  56
  57 int
  58 sched_getparam(pid_t pid, struct sched_param *param)
  59 {
  60
  61         return _sched_getparam(pid, P_ALL_LWPS, NULL, param);
  62 }
  63
  64 int
  65 sched_setscheduler(pid_t pid, int policy, const struct sched_param *param)
  66 {
  67         struct sched_param sp;
  68         int ret, old_policy;
  69
  70         ret = _sched_getparam(pid, P_ALL_LWPS, &old_policy, &sp);
  71         if (ret < 0)
  72                 return ret;
  73
  74         memset(&sp, 0, sizeof(struct sched_param));
  75         sp.sched_priority = param->sched_priority;
  76         ret = _sched_setparam(pid, P_ALL_LWPS, policy, &sp);
  77         if (ret < 0)
  78                 return ret;
  79
  80         return old_policy;
  81 }
  82
  83 int
  84 sched_getscheduler(pid_t pid)
  85 {
  86         struct sched_param sp;
  87         int ret, policy;
  88
  89         ret = _sched_getparam(pid, P_ALL_LWPS, &policy, &sp);
  90         if (ret < 0)
  91                 return ret;
  92
  93         return policy;
  94 }
  95
  96 /*
  97  * Scheduling priorities.
  98  */
  99
 100 int
 101 sched_get_priority_max(int policy)
 102 {
 103
 104         if (policy < SCHED_OTHER || policy > SCHED_RR) {
 105                 errno = EINVAL;
 106                 return -1;
 107         }
 108         return (int)sysconf(_SC_SCHED_PRI_MAX);
 109 }
 110
 111 int
 112 sched_get_priority_min(int policy)
 113 {
 114
 115         if (policy < SCHED_OTHER || policy > SCHED_RR) {
 116                 errno = EINVAL;
 117                 return -1;
 118         }
 119         return (int)sysconf(_SC_SCHED_PRI_MIN);
 120 }
 121
 122 int
 123 /*ARGSUSED*/
 124 sched_rr_get_interval(pid_t pid, struct timespec *interval)
 125 {
 126
 127         if (pid && kill(pid, 0) == -1)
 128                 return -1;
 129         interval->tv_sec = 0;
 130         interval->tv_nsec = sysconf(_SC_SCHED_RT_TS) * 1000;
 131         return 0;
 132 }
 133
 134 /*
 135  * Process affinity.
 136  */
 137
 138 int
 139 sched_getaffinity_np(pid_t pid, size_t size, cpuset_t *cpuset)
 140 {
 141
 142         return _sched_getaffinity(pid, P_ALL_LWPS, size, cpuset);
 143 }
 144
 145 int
 146 sched_setaffinity_np(pid_t pid, size_t size, cpuset_t *cpuset)
 147 {
 148
 149         return _sched_setaffinity(pid, P_ALL_LWPS, size, cpuset);
 150 }