osfmk/kern/sched.h

   1 /*
   2  * Copyright (c) 2000-2009 Apple Inc. All rights reserved.
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  10  * may not be used to create, or enable the creation or redistribution of,
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  13  * terms of an Apple operating system software license agreement.
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  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
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  23  * Please see the License for the specific language governing rights and
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  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  */
  58 /*
  59  *      File:   sched.h
  60  *      Author: Avadis Tevanian, Jr.
  61  *      Date:   1985
  62  *
  63  *      Header file for scheduler.
  64  *
  65  */
  66
  67 #ifndef _KERN_SCHED_H_
  68 #define _KERN_SCHED_H_
  69
  70 #include <stat_time.h>
  71
  72 #include <mach/policy.h>
  73 #include <kern/kern_types.h>
  74 #include <kern/queue.h>
  75 #include <kern/lock.h>
  76 #include <kern/macro_help.h>
  77 #include <kern/timer_call.h>
  78 #include <kern/ast.h>
  79
  80 #define NRQS            128                             /* 128 levels per run queue */
  81 #define NRQBM           (NRQS / 32)             /* number of words per bit map */
  82
  83 #define MAXPRI          (NRQS-1)
  84 #define MINPRI          IDLEPRI                 /* lowest legal priority schedulable */
  85 #define IDLEPRI         0                               /* idle thread priority */
  86 #define DEPRESSPRI      MINPRI                  /* depress priority */
  87
  88 /*
  89  *      High-level priority assignments
  90  *
  91  *************************************************************************
  92  * 127          Reserved (real-time)
  93  *                              A
  94  *                              +
  95  *                      (32 levels)
  96  *                              +
  97  *                              V
  98  * 96           Reserved (real-time)
  99  * 95           Kernel mode only
 100  *                              A
 101  *                              +
 102  *                      (16 levels)
 103  *                              +
 104  *                              V
 105  * 80           Kernel mode only
 106  * 79           System high priority
 107  *                              A
 108  *                              +
 109  *                      (16 levels)
 110  *                              +
 111  *                              V
 112  * 64           System high priority
 113  * 63           Elevated priorities
 114  *                              A
 115  *                              +
 116  *                      (12 levels)
 117  *                              +
 118  *                              V
 119  * 52           Elevated priorities
 120  * 51           Elevated priorities (incl. BSD +nice)
 121  *                              A
 122  *                              +
 123  *                      (20 levels)
 124  *                              +
 125  *                              V
 126  * 32           Elevated priorities (incl. BSD +nice)
 127  * 31           Default (default base for threads)
 128  * 30           Lowered priorities (incl. BSD -nice)
 129  *                              A
 130  *                              +
 131  *                      (20 levels)
 132  *                              +
 133  *                              V
 134  * 11           Lowered priorities (incl. BSD -nice)
 135  * 10           Lowered priorities (aged pri's)
 136  *                              A
 137  *                              +
 138  *                      (11 levels)
 139  *                              +
 140  *                              V
 141  * 0            Lowered priorities (aged pri's / idle)
 142  *************************************************************************
 143  */
 144
 145 #define BASEPRI_RTQUEUES        (BASEPRI_REALTIME + 1)                          /* 97 */
 146 #define BASEPRI_REALTIME        (MAXPRI - (NRQS / 4) + 1)                       /* 96 */
 147
 148 #define MAXPRI_KERNEL           (BASEPRI_REALTIME - 1)                          /* 95 */
 149 #define BASEPRI_PREEMPT         (MAXPRI_KERNEL - 2)                                     /* 93 */
 150 #define BASEPRI_KERNEL          (MINPRI_KERNEL + 1)                                     /* 81 */
 151 #define MINPRI_KERNEL           (MAXPRI_KERNEL - (NRQS / 8) + 1)        /* 80 */
 152
 153 #define MAXPRI_RESERVED         (MINPRI_KERNEL - 1)                                     /* 79 */
 154 #define MINPRI_RESERVED         (MAXPRI_RESERVED - (NRQS / 8) + 1)      /* 64 */
 155
 156 #define MAXPRI_USER                     (MINPRI_RESERVED - 1)                           /* 63 */
 157 #define BASEPRI_CONTROL         (BASEPRI_DEFAULT + 17)                          /* 48 */
 158 #define BASEPRI_FOREGROUND      (BASEPRI_DEFAULT + 16)                          /* 47 */
 159 #define BASEPRI_BACKGROUND      (BASEPRI_DEFAULT + 15)                          /* 46 */
 160 #define BASEPRI_DEFAULT         (MAXPRI_USER - (NRQS / 4))                      /* 31 */
 161 #define MINPRI_USER                     MINPRI                                                          /*  0 */
 162
 163 /*
 164  *      Macro to check for invalid priorities.
 165  */
 166 #define invalid_pri(pri) ((pri) < MINPRI || (pri) > MAXPRI)
 167
 168 struct run_queue {
 169         int                                     highq;                          /* highest runnable queue */
 170         int                                     bitmap[NRQBM];          /* run queue bitmap array */
 171         int                                     count;                          /* # of threads total */
 172         int                                     urgency;                        /* level of preemption urgency */
 173         queue_head_t            queues[NRQS];           /* one for each priority */
 174 };
 175
 176 typedef struct run_queue        *run_queue_t;
 177 #define RUN_QUEUE_NULL          ((run_queue_t) 0)
 178
 179 #define first_timeslice(processor)              ((processor)->timeslice > 0)
 180
 181 #define thread_quantum_init(thread)                                                     \
 182 MACRO_BEGIN                                                                                                     \
 183         (thread)->current_quantum =                                                     \
 184                 ((thread)->sched_mode & TH_MODE_REALTIME)?                      \
 185                         (thread)->realtime.computation: std_quantum;    \
 186 MACRO_END
 187
 188 extern struct run_queue         rt_runq;
 189
 190 /*
 191  *      Scheduler routines.
 192  */
 193
 194 /* Remove thread from its run queue */
 195 extern boolean_t        run_queue_remove(
 196                                                 thread_t        thread);
 197
 198 /* Handle quantum expiration for an executing thread */
 199 extern void             thread_quantum_expire(
 200                                         timer_call_param_t      processor,
 201                                         timer_call_param_t      thread);
 202
 203 /* Context switch check for current processor */
 204 extern ast_t    csw_check(processor_t           processor);
 205
 206 extern uint32_t std_quantum, min_std_quantum;
 207 extern uint32_t std_quantum_us;
 208
 209 extern uint32_t max_rt_quantum, min_rt_quantum;
 210
 211 extern uint32_t sched_cswtime;
 212
 213 /*
 214  *      Age usage (1 << SCHED_TICK_SHIFT) times per second.
 215  */
 216 #define SCHED_TICK_SHIFT        3
 217
 218 extern unsigned         sched_tick;
 219 extern uint32_t         sched_tick_interval;
 220
 221 /* Periodic computation of various averages */
 222 extern void             compute_averages(void);
 223
 224 extern void             compute_averunnable(
 225                                         void                    *nrun);
 226
 227 extern void             compute_stack_target(
 228                                         void                    *arg);
 229
 230 extern void             compute_memory_pressure(
 231                                         void                    *arg);
 232
 233 /*
 234  *      Conversion factor from usage
 235  *      to priority.
 236  */
 237 extern uint32_t         sched_pri_shift;
 238 extern uint32_t         sched_fixed_shift;
 239 extern int8_t           sched_load_shifts[NRQS];
 240
 241 extern int32_t          sched_poll_yield_shift;
 242 extern uint32_t         sched_safe_duration;
 243
 244 extern uint32_t         sched_run_count, sched_share_count;
 245 extern uint32_t         sched_load_average, sched_mach_factor;
 246
 247 extern uint32_t         avenrun[3], mach_factor[3];
 248
 249 extern uint64_t         max_unsafe_computation;
 250 extern uint64_t         max_poll_computation;
 251
 252 #define sched_run_incr()                        \
 253 MACRO_BEGIN                                                                                                     \
 254         machine_run_count(hw_atomic_add(&sched_run_count, 1));  \
 255 MACRO_END
 256
 257 #define sched_run_decr()                        \
 258 MACRO_BEGIN                                                                                                     \
 259         machine_run_count(hw_atomic_sub(&sched_run_count, 1));  \
 260 MACRO_END
 261
 262 #define sched_share_incr()                      \
 263 MACRO_BEGIN                                                                                     \
 264         (void)hw_atomic_add(&sched_share_count, 1);             \
 265 MACRO_END
 266
 267 #define sched_share_decr()                      \
 268 MACRO_BEGIN                                                                                     \
 269         (void)hw_atomic_sub(&sched_share_count, 1);             \
 270 MACRO_END
 271
 272 /*
 273  *      thread_timer_delta macro takes care of both thread timers.
 274  */
 275 #define thread_timer_delta(thread, delta)                                       \
 276 MACRO_BEGIN                                                                                                     \
 277         (delta) = (typeof(delta))timer_delta(&(thread)->system_timer,                   \
 278                                                         &(thread)->system_timer_save);  \
 279         (delta) += (typeof(delta))timer_delta(&(thread)->user_timer,                    \
 280                                                         &(thread)->user_timer_save);    \
 281 MACRO_END
 282
 283 #endif  /* _KERN_SCHED_H_ */