osfmk/kern/sched_proto.c

   1 /*
   2  * Copyright (c) 2009 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <mach/mach_types.h>
  30 #include <mach/machine.h>
  31 #include <mach/policy.h>
  32 #include <mach/sync_policy.h>
  33 #include <mach/thread_act.h>
  34
  35 #include <machine/machine_routines.h>
  36 #include <machine/sched_param.h>
  37 #include <machine/machine_cpu.h>
  38
  39 #include <kern/kern_types.h>
  40 #include <kern/clock.h>
  41 #include <kern/counters.h>
  42 #include <kern/cpu_number.h>
  43 #include <kern/cpu_data.h>
  44 #include <kern/debug.h>
  45 #include <kern/macro_help.h>
  46 #include <kern/machine.h>
  47 #include <kern/misc_protos.h>
  48 #include <kern/processor.h>
  49 #include <kern/queue.h>
  50 #include <kern/sched.h>
  51 #include <kern/sched_prim.h>
  52 #include <kern/syscall_subr.h>
  53 #include <kern/task.h>
  54 #include <kern/thread.h>
  55
  56 #include <vm/pmap.h>
  57 #include <vm/vm_kern.h>
  58 #include <vm/vm_map.h>
  59
  60 #include <mach/sdt.h>
  61
  62 #include <sys/kdebug.h>
  63
  64 static void
  65 sched_proto_init(void);
  66
  67 static void
  68 sched_proto_timebase_init(void);
  69
  70 static void
  71 sched_proto_processor_init(processor_t processor);
  72
  73 static void
  74 sched_proto_pset_init(processor_set_t pset);
  75
  76 static void
  77 sched_proto_maintenance_continuation(void);
  78
  79 static thread_t
  80 sched_proto_choose_thread(processor_t           processor,
  81     int                            priority,
  82     ast_t                          reason);
  83
  84 static thread_t
  85 sched_proto_steal_thread(processor_set_t                pset);
  86
  87 static int
  88 sched_proto_compute_priority(thread_t thread);
  89
  90 static processor_t
  91 sched_proto_choose_processor(   processor_set_t         pset,
  92     processor_t                     processor,
  93     thread_t                        thread);
  94
  95
  96 static boolean_t
  97 sched_proto_processor_enqueue(
  98         processor_t                    processor,
  99         thread_t                       thread,
 100         sched_options_t                options);
 101
 102 static void
 103 sched_proto_processor_queue_shutdown(
 104         processor_t                    processor);
 105
 106 static boolean_t
 107 sched_proto_processor_queue_remove(
 108         processor_t                 processor,
 109         thread_t                thread);
 110
 111 static boolean_t
 112 sched_proto_processor_queue_empty(processor_t           processor);
 113
 114 static boolean_t
 115 sched_proto_processor_queue_has_priority(processor_t            processor,
 116     int                            priority,
 117     boolean_t              gte);
 118
 119 static boolean_t
 120 sched_proto_priority_is_urgent(int priority);
 121
 122 static ast_t
 123 sched_proto_processor_csw_check(processor_t processor);
 124
 125 static uint32_t
 126 sched_proto_initial_quantum_size(thread_t thread);
 127
 128 static sched_mode_t
 129 sched_proto_initial_thread_sched_mode(task_t parent_task);
 130
 131 static boolean_t
 132 sched_proto_can_update_priority(thread_t        thread);
 133
 134 static void
 135 sched_proto_update_priority(thread_t    thread);
 136
 137 static void
 138 sched_proto_lightweight_update_priority(thread_t        thread);
 139
 140 static void
 141 sched_proto_quantum_expire(thread_t     thread);
 142
 143 static int
 144 sched_proto_processor_runq_count(processor_t   processor);
 145
 146 static uint64_t
 147 sched_proto_processor_runq_stats_count_sum(processor_t   processor);
 148
 149 static int
 150 sched_proto_processor_bound_count(processor_t   processor);
 151
 152 static void
 153 sched_proto_thread_update_scan(sched_update_scan_context_t scan_context);
 154
 155
 156 const struct sched_dispatch_table sched_proto_dispatch = {
 157         .sched_name                                     = "proto",
 158         .init                                           = sched_proto_init,
 159         .timebase_init                                  = sched_proto_timebase_init,
 160         .processor_init                                 = sched_proto_processor_init,
 161         .pset_init                                      = sched_proto_pset_init,
 162         .maintenance_continuation                       = sched_proto_maintenance_continuation,
 163         .choose_thread                                  = sched_proto_choose_thread,
 164         .steal_thread_enabled                           = sched_steal_thread_DISABLED,
 165         .steal_thread                                   = sched_proto_steal_thread,
 166         .compute_timeshare_priority                     = sched_proto_compute_priority,
 167         .choose_processor                               = sched_proto_choose_processor,
 168         .processor_enqueue                              = sched_proto_processor_enqueue,
 169         .processor_queue_shutdown                       = sched_proto_processor_queue_shutdown,
 170         .processor_queue_remove                         = sched_proto_processor_queue_remove,
 171         .processor_queue_empty                          = sched_proto_processor_queue_empty,
 172         .priority_is_urgent                             = sched_proto_priority_is_urgent,
 173         .processor_csw_check                            = sched_proto_processor_csw_check,
 174         .processor_queue_has_priority                   = sched_proto_processor_queue_has_priority,
 175         .initial_quantum_size                           = sched_proto_initial_quantum_size,
 176         .initial_thread_sched_mode                      = sched_proto_initial_thread_sched_mode,
 177         .can_update_priority                            = sched_proto_can_update_priority,
 178         .update_priority                                = sched_proto_update_priority,
 179         .lightweight_update_priority                    = sched_proto_lightweight_update_priority,
 180         .quantum_expire                                 = sched_proto_quantum_expire,
 181         .processor_runq_count                           = sched_proto_processor_runq_count,
 182         .processor_runq_stats_count_sum                 = sched_proto_processor_runq_stats_count_sum,
 183         .processor_bound_count                          = sched_proto_processor_bound_count,
 184         .thread_update_scan                             = sched_proto_thread_update_scan,
 185         .multiple_psets_enabled                         = TRUE,
 186         .sched_groups_enabled                           = FALSE,
 187         .avoid_processor_enabled                        = FALSE,
 188         .thread_avoid_processor                         = NULL,
 189         .processor_balance                              = sched_SMT_balance,
 190
 191         .rt_runq                                        = sched_rtglobal_runq,
 192         .rt_init                                        = sched_rtglobal_init,
 193         .rt_queue_shutdown                              = sched_rtglobal_queue_shutdown,
 194         .rt_runq_scan                                   = sched_rtglobal_runq_scan,
 195         .rt_runq_count_sum                              = sched_rtglobal_runq_count_sum,
 196
 197         .qos_max_parallelism                            = sched_qos_max_parallelism,
 198         .check_spill                                    = sched_check_spill,
 199         .ipi_policy                                     = sched_ipi_policy,
 200         .thread_should_yield                            = sched_thread_should_yield,
 201         .run_count_incr                                 = sched_run_incr,
 202         .run_count_decr                                 = sched_run_decr,
 203         .update_thread_bucket                           = sched_update_thread_bucket,
 204         .pset_made_schedulable                          = sched_pset_made_schedulable,
 205 };
 206
 207 static struct run_queue *global_runq;
 208 static struct run_queue global_runq_storage;
 209
 210 #define GLOBAL_RUNQ             ((processor_t)-2)
 211 decl_simple_lock_data(static, global_runq_lock);
 212
 213 extern int      max_unsafe_quanta;
 214
 215 static uint32_t proto_quantum_us;
 216 static uint32_t proto_quantum;
 217
 218 static uint32_t runqueue_generation;
 219
 220 static processor_t proto_processor;
 221
 222 static uint64_t                 sched_proto_tick_deadline;
 223 static uint32_t                 sched_proto_tick;
 224
 225 static void
 226 sched_proto_init(void)
 227 {
 228         proto_quantum_us = 10 * 1000;
 229
 230         printf("standard proto timeslicing quantum is %d us\n", proto_quantum_us);
 231
 232         simple_lock_init(&global_runq_lock, 0);
 233         global_runq = &global_runq_storage;
 234         run_queue_init(global_runq);
 235         runqueue_generation = 0;
 236
 237         proto_processor = master_processor;
 238 }
 239
 240 static void
 241 sched_proto_timebase_init(void)
 242 {
 243         uint64_t        abstime;
 244
 245         /* standard timeslicing quantum */
 246         clock_interval_to_absolutetime_interval(
 247                 proto_quantum_us, NSEC_PER_USEC, &abstime);
 248         assert((abstime >> 32) == 0 && (uint32_t)abstime != 0);
 249         proto_quantum = (uint32_t)abstime;
 250
 251         thread_depress_time = 1 * proto_quantum;
 252         default_timeshare_computation = proto_quantum / 2;
 253         default_timeshare_constraint = proto_quantum;
 254
 255         max_unsafe_computation = max_unsafe_quanta * proto_quantum;
 256         sched_safe_duration = 2 * max_unsafe_quanta * proto_quantum;
 257 }
 258
 259 static void
 260 sched_proto_processor_init(processor_t processor __unused)
 261 {
 262         /* No per-processor state */
 263 }
 264
 265 static void
 266 sched_proto_pset_init(processor_set_t pset __unused)
 267 {
 268 }
 269
 270 static void
 271 sched_proto_maintenance_continuation(void)
 272 {
 273         uint64_t                        abstime = mach_absolute_time();
 274
 275         sched_proto_tick++;
 276
 277         /* Every 8 seconds, switch to another processor */
 278         if ((sched_proto_tick & 0x7) == 0) {
 279                 processor_t new_processor;
 280
 281                 new_processor = proto_processor->processor_list;
 282                 if (new_processor == PROCESSOR_NULL) {
 283                         proto_processor = master_processor;
 284                 } else {
 285                         proto_processor = new_processor;
 286                 }
 287         }
 288
 289
 290         /*
 291          *  Compute various averages.
 292          */
 293         compute_averages(1);
 294
 295         if (sched_proto_tick_deadline == 0) {
 296                 sched_proto_tick_deadline = abstime;
 297         }
 298
 299         clock_deadline_for_periodic_event(sched_one_second_interval, abstime,
 300             &sched_proto_tick_deadline);
 301
 302         assert_wait_deadline((event_t)sched_proto_maintenance_continuation, THREAD_UNINT, sched_proto_tick_deadline);
 303         thread_block((thread_continue_t)sched_proto_maintenance_continuation);
 304         /*NOTREACHED*/
 305 }
 306
 307 static thread_t
 308 sched_proto_choose_thread(processor_t           processor,
 309     int                           priority,
 310     ast_t                         reason __unused)
 311 {
 312         run_queue_t             rq = global_runq;
 313         circle_queue_t          queue;
 314         int                             pri, count;
 315         thread_t                thread;
 316
 317
 318         simple_lock(&global_runq_lock, LCK_GRP_NULL);
 319
 320         queue = rq->queues + rq->highq;
 321         pri = rq->highq;
 322         count = rq->count;
 323
 324         /*
 325          * Since we don't depress priorities, a high priority thread
 326          * may get selected over and over again. Put a runqueue
 327          * generation number in the thread structure so that we
 328          * can ensure that we've cycled through all runnable tasks
 329          * before coming back to a high priority thread. This isn't
 330          * perfect, especially if the number of runnable threads always
 331          * stays high, but is a workable approximation
 332          */
 333
 334         while (count > 0 && pri >= priority) {
 335                 cqe_foreach_element_safe(thread, queue, runq_links) {
 336                         if ((thread->bound_processor == PROCESSOR_NULL ||
 337                             thread->bound_processor == processor) &&
 338                             runqueue_generation != thread->runqueue_generation) {
 339                                 circle_dequeue(queue, &thread->runq_links);
 340
 341                                 thread->runq = PROCESSOR_NULL;
 342                                 thread->runqueue_generation = runqueue_generation;
 343                                 SCHED_STATS_RUNQ_CHANGE(&rq->runq_stats, rq->count);
 344                                 rq->count--;
 345                                 if (circle_queue_empty(queue)) {
 346                                         bitmap_clear(rq->bitmap, pri);
 347                                         rq->highq = bitmap_first(rq->bitmap, NRQS);
 348                                 }
 349
 350                                 simple_unlock(&global_runq_lock);
 351                                 return thread;
 352                         }
 353                         count--;
 354
 355                         thread = (thread_t)queue_next((queue_entry_t)thread);
 356                 }
 357
 358                 queue--; pri--;
 359         }
 360
 361         runqueue_generation++;
 362
 363         simple_unlock(&global_runq_lock);
 364         return THREAD_NULL;
 365 }
 366
 367 static thread_t
 368 sched_proto_steal_thread(processor_set_t                pset)
 369 {
 370         pset_unlock(pset);
 371
 372         return THREAD_NULL;
 373 }
 374
 375 static int
 376 sched_proto_compute_priority(thread_t thread)
 377 {
 378         return thread->base_pri;
 379 }
 380
 381 static processor_t
 382 sched_proto_choose_processor(   processor_set_t         pset,
 383     processor_t                    processor,
 384     thread_t                       thread __unused)
 385 {
 386         processor = proto_processor;
 387
 388         /*
 389          *      Check that the correct processor set is
 390          *      returned locked.
 391          */
 392         if (pset != processor->processor_set) {
 393                 pset_unlock(pset);
 394
 395                 pset = processor->processor_set;
 396                 pset_lock(pset);
 397         }
 398
 399         return processor;
 400 }
 401
 402 static boolean_t
 403 sched_proto_processor_enqueue(
 404         processor_t                    processor __unused,
 405         thread_t                       thread,
 406         sched_options_t                options)
 407 {
 408         run_queue_t             rq = global_runq;
 409         boolean_t               result;
 410
 411         simple_lock(&global_runq_lock, LCK_GRP_NULL);
 412         result = run_queue_enqueue(rq, thread, options);
 413         thread->runq = GLOBAL_RUNQ;
 414         simple_unlock(&global_runq_lock);
 415
 416         return result;
 417 }
 418
 419 static void
 420 sched_proto_processor_queue_shutdown(
 421         processor_t                    processor)
 422 {
 423         /* With a global runqueue, just stop choosing this processor */
 424         (void)processor;
 425 }
 426
 427 static boolean_t
 428 sched_proto_processor_queue_remove(
 429         processor_t                     processor,
 430         thread_t                thread)
 431 {
 432         void *                  rqlock;
 433         run_queue_t             rq;
 434
 435         rqlock = &global_runq_lock;
 436         rq = global_runq;
 437
 438         simple_lock(rqlock, LCK_GRP_NULL);
 439         if (processor == thread->runq) {
 440                 /*
 441                  *      Thread is on a run queue and we have a lock on
 442                  *      that run queue.
 443                  */
 444                 run_queue_remove(rq, thread);
 445         } else {
 446                 /*
 447                  *      The thread left the run queue before we could
 448                  *      lock the run queue.
 449                  */
 450                 assert(thread->runq == PROCESSOR_NULL);
 451                 processor = PROCESSOR_NULL;
 452         }
 453
 454         simple_unlock(rqlock);
 455
 456         return processor != PROCESSOR_NULL;
 457 }
 458
 459 static boolean_t
 460 sched_proto_processor_queue_empty(processor_t           processor __unused)
 461 {
 462         boolean_t result;
 463
 464         result = (global_runq->count == 0);
 465
 466         return result;
 467 }
 468
 469 static boolean_t
 470 sched_proto_processor_queue_has_priority(processor_t            processor __unused,
 471     int                            priority,
 472     boolean_t              gte)
 473 {
 474         boolean_t result;
 475
 476         simple_lock(&global_runq_lock, LCK_GRP_NULL);
 477
 478         if (gte) {
 479                 result = global_runq->highq >= priority;
 480         } else {
 481                 result = global_runq->highq > priority;
 482         }
 483
 484         simple_unlock(&global_runq_lock);
 485
 486         return result;
 487 }
 488
 489 /* Implement sched_preempt_pri in code */
 490 static boolean_t
 491 sched_proto_priority_is_urgent(int priority)
 492 {
 493         if (priority <= BASEPRI_FOREGROUND) {
 494                 return FALSE;
 495         }
 496
 497         if (priority < MINPRI_KERNEL) {
 498                 return TRUE;
 499         }
 500
 501         if (priority >= BASEPRI_PREEMPT) {
 502                 return TRUE;
 503         }
 504
 505         return FALSE;
 506 }
 507
 508 static ast_t
 509 sched_proto_processor_csw_check(processor_t processor)
 510 {
 511         run_queue_t             runq;
 512         int                             count, urgency;
 513
 514         runq = global_runq;
 515         count = runq->count;
 516         urgency = runq->urgency;
 517
 518         if (count > 0) {
 519                 if (urgency > 0) {
 520                         return AST_PREEMPT | AST_URGENT;
 521                 }
 522
 523                 return AST_PREEMPT;
 524         }
 525
 526         if (proto_processor != processor) {
 527                 return AST_PREEMPT;
 528         }
 529
 530         return AST_NONE;
 531 }
 532
 533 static uint32_t
 534 sched_proto_initial_quantum_size(thread_t thread __unused)
 535 {
 536         return proto_quantum;
 537 }
 538
 539 static sched_mode_t
 540 sched_proto_initial_thread_sched_mode(task_t parent_task)
 541 {
 542         if (parent_task == kernel_task) {
 543                 return TH_MODE_FIXED;
 544         } else {
 545                 return TH_MODE_TIMESHARE;
 546         }
 547 }
 548
 549 static boolean_t
 550 sched_proto_can_update_priority(thread_t        thread __unused)
 551 {
 552         return FALSE;
 553 }
 554
 555 static void
 556 sched_proto_update_priority(thread_t    thread __unused)
 557 {
 558 }
 559
 560 static void
 561 sched_proto_lightweight_update_priority(thread_t        thread __unused)
 562 {
 563 }
 564
 565 static void
 566 sched_proto_quantum_expire(thread_t    thread __unused)
 567 {
 568 }
 569
 570 static int
 571 sched_proto_processor_runq_count(processor_t   processor)
 572 {
 573         if (master_processor == processor) {
 574                 return global_runq->count;
 575         } else {
 576                 return 0;
 577         }
 578 }
 579
 580 static uint64_t
 581 sched_proto_processor_runq_stats_count_sum(processor_t   processor)
 582 {
 583         if (master_processor == processor) {
 584                 return global_runq->runq_stats.count_sum;
 585         } else {
 586                 return 0ULL;
 587         }
 588 }
 589
 590 static int
 591 sched_proto_processor_bound_count(__unused processor_t   processor)
 592 {
 593         return 0;
 594 }
 595
 596 static void
 597 sched_proto_thread_update_scan(__unused sched_update_scan_context_t scan_context)
 598 {
 599 }