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_node                                    = sched_choose_node,
 168         .choose_processor                               = sched_proto_choose_processor,
 169         .processor_enqueue                              = sched_proto_processor_enqueue,
 170         .processor_queue_shutdown                       = sched_proto_processor_queue_shutdown,
 171         .processor_queue_remove                         = sched_proto_processor_queue_remove,
 172         .processor_queue_empty                          = sched_proto_processor_queue_empty,
 173         .priority_is_urgent                             = sched_proto_priority_is_urgent,
 174         .processor_csw_check                            = sched_proto_processor_csw_check,
 175         .processor_queue_has_priority                   = sched_proto_processor_queue_has_priority,
 176         .initial_quantum_size                           = sched_proto_initial_quantum_size,
 177         .initial_thread_sched_mode                      = sched_proto_initial_thread_sched_mode,
 178         .can_update_priority                            = sched_proto_can_update_priority,
 179         .update_priority                                = sched_proto_update_priority,
 180         .lightweight_update_priority                    = sched_proto_lightweight_update_priority,
 181         .quantum_expire                                 = sched_proto_quantum_expire,
 182         .processor_runq_count                           = sched_proto_processor_runq_count,
 183         .processor_runq_stats_count_sum                 = sched_proto_processor_runq_stats_count_sum,
 184         .processor_bound_count                          = sched_proto_processor_bound_count,
 185         .thread_update_scan                             = sched_proto_thread_update_scan,
 186         .multiple_psets_enabled                         = TRUE,
 187         .sched_groups_enabled                           = FALSE,
 188         .avoid_processor_enabled                        = FALSE,
 189         .thread_avoid_processor                         = NULL,
 190         .processor_balance                              = sched_SMT_balance,
 191
 192         .rt_runq                                        = sched_rtlocal_runq,
 193         .rt_init                                        = sched_rtlocal_init,
 194         .rt_queue_shutdown                              = sched_rtlocal_queue_shutdown,
 195         .rt_runq_scan                                   = sched_rtlocal_runq_scan,
 196         .rt_runq_count_sum                              = sched_rtlocal_runq_count_sum,
 197
 198         .qos_max_parallelism                            = sched_qos_max_parallelism,
 199         .check_spill                                    = sched_check_spill,
 200         .ipi_policy                                     = sched_ipi_policy,
 201         .thread_should_yield                            = sched_thread_should_yield,
 202         .run_count_incr                                 = sched_run_incr,
 203         .run_count_decr                                 = sched_run_decr,
 204         .update_thread_bucket                           = sched_update_thread_bucket,
 205         .pset_made_schedulable                          = sched_pset_made_schedulable,
 206 };
 207
 208 static struct run_queue *global_runq;
 209 static struct run_queue global_runq_storage;
 210
 211 #define GLOBAL_RUNQ             ((processor_t)-2)
 212 decl_simple_lock_data(static, global_runq_lock);
 213
 214 extern int      max_unsafe_quanta;
 215
 216 static uint32_t proto_quantum_us;
 217 static uint32_t proto_quantum;
 218
 219 static uint32_t runqueue_generation;
 220
 221 static processor_t proto_processor;
 222
 223 static uint64_t                 sched_proto_tick_deadline;
 224 static uint32_t                 sched_proto_tick;
 225
 226 static void
 227 sched_proto_init(void)
 228 {
 229         proto_quantum_us = 10 * 1000;
 230
 231         printf("standard proto timeslicing quantum is %d us\n", proto_quantum_us);
 232
 233         simple_lock_init(&global_runq_lock, 0);
 234         global_runq = &global_runq_storage;
 235         run_queue_init(global_runq);
 236         runqueue_generation = 0;
 237
 238         proto_processor = master_processor;
 239 }
 240
 241 static void
 242 sched_proto_timebase_init(void)
 243 {
 244         uint64_t        abstime;
 245
 246         /* standard timeslicing quantum */
 247         clock_interval_to_absolutetime_interval(
 248                 proto_quantum_us, NSEC_PER_USEC, &abstime);
 249         assert((abstime >> 32) == 0 && (uint32_t)abstime != 0);
 250         proto_quantum = (uint32_t)abstime;
 251
 252         thread_depress_time = 1 * proto_quantum;
 253         default_timeshare_computation = proto_quantum / 2;
 254         default_timeshare_constraint = proto_quantum;
 255
 256         max_unsafe_computation = max_unsafe_quanta * proto_quantum;
 257         sched_safe_duration = 2 * max_unsafe_quanta * proto_quantum;
 258 }
 259
 260 static void
 261 sched_proto_processor_init(processor_t processor __unused)
 262 {
 263         /* No per-processor state */
 264 }
 265
 266 static void
 267 sched_proto_pset_init(processor_set_t pset __unused)
 268 {
 269 }
 270
 271 static void
 272 sched_proto_maintenance_continuation(void)
 273 {
 274         uint64_t                        abstime = mach_absolute_time();
 275
 276         sched_proto_tick++;
 277
 278         /* Every 8 seconds, switch to another processor */
 279         if ((sched_proto_tick & 0x7) == 0) {
 280                 processor_t new_processor;
 281
 282                 new_processor = proto_processor->processor_list;
 283                 if (new_processor == PROCESSOR_NULL) {
 284                         proto_processor = master_processor;
 285                 } else {
 286                         proto_processor = new_processor;
 287                 }
 288         }
 289
 290
 291         /*
 292          *  Compute various averages.
 293          */
 294         compute_averages(1);
 295
 296         if (sched_proto_tick_deadline == 0) {
 297                 sched_proto_tick_deadline = abstime;
 298         }
 299
 300         clock_deadline_for_periodic_event(sched_one_second_interval, abstime,
 301             &sched_proto_tick_deadline);
 302
 303         assert_wait_deadline((event_t)sched_proto_maintenance_continuation, THREAD_UNINT, sched_proto_tick_deadline);
 304         thread_block((thread_continue_t)sched_proto_maintenance_continuation);
 305         /*NOTREACHED*/
 306 }
 307
 308 static thread_t
 309 sched_proto_choose_thread(processor_t           processor,
 310     int                           priority,
 311     ast_t                         reason __unused)
 312 {
 313         run_queue_t             rq = global_runq;
 314         circle_queue_t          queue;
 315         int                             pri, count;
 316         thread_t                thread;
 317
 318
 319         simple_lock(&global_runq_lock, LCK_GRP_NULL);
 320
 321         queue = rq->queues + rq->highq;
 322         pri = rq->highq;
 323         count = rq->count;
 324
 325         /*
 326          * Since we don't depress priorities, a high priority thread
 327          * may get selected over and over again. Put a runqueue
 328          * generation number in the thread structure so that we
 329          * can ensure that we've cycled through all runnable tasks
 330          * before coming back to a high priority thread. This isn't
 331          * perfect, especially if the number of runnable threads always
 332          * stays high, but is a workable approximation
 333          */
 334
 335         while (count > 0 && pri >= priority) {
 336                 cqe_foreach_element_safe(thread, queue, runq_links) {
 337                         if ((thread->bound_processor == PROCESSOR_NULL ||
 338                             thread->bound_processor == processor) &&
 339                             runqueue_generation != thread->runqueue_generation) {
 340                                 circle_dequeue(queue, &thread->runq_links);
 341
 342                                 thread->runq = PROCESSOR_NULL;
 343                                 thread->runqueue_generation = runqueue_generation;
 344                                 SCHED_STATS_RUNQ_CHANGE(&rq->runq_stats, rq->count);
 345                                 rq->count--;
 346                                 if (circle_queue_empty(queue)) {
 347                                         bitmap_clear(rq->bitmap, pri);
 348                                         rq->highq = bitmap_first(rq->bitmap, NRQS);
 349                                 }
 350
 351                                 simple_unlock(&global_runq_lock);
 352                                 return thread;
 353                         }
 354                         count--;
 355
 356                         thread = (thread_t)queue_next((queue_entry_t)thread);
 357                 }
 358
 359                 queue--; pri--;
 360         }
 361
 362         runqueue_generation++;
 363
 364         simple_unlock(&global_runq_lock);
 365         return THREAD_NULL;
 366 }
 367
 368 static thread_t
 369 sched_proto_steal_thread(processor_set_t                pset)
 370 {
 371         pset_unlock(pset);
 372
 373         return THREAD_NULL;
 374 }
 375
 376 static int
 377 sched_proto_compute_priority(thread_t thread)
 378 {
 379         return thread->base_pri;
 380 }
 381
 382 static processor_t
 383 sched_proto_choose_processor(   processor_set_t         pset,
 384     processor_t                    processor,
 385     thread_t                       thread __unused)
 386 {
 387         processor = proto_processor;
 388
 389         /*
 390          *      Check that the correct processor set is
 391          *      returned locked.
 392          */
 393         if (pset != processor->processor_set) {
 394                 pset_unlock(pset);
 395
 396                 pset = processor->processor_set;
 397                 pset_lock(pset);
 398         }
 399
 400         return processor;
 401 }
 402
 403 static boolean_t
 404 sched_proto_processor_enqueue(
 405         processor_t                    processor __unused,
 406         thread_t                       thread,
 407         sched_options_t                options)
 408 {
 409         run_queue_t             rq = global_runq;
 410         boolean_t               result;
 411
 412         simple_lock(&global_runq_lock, LCK_GRP_NULL);
 413         result = run_queue_enqueue(rq, thread, options);
 414         thread->runq = GLOBAL_RUNQ;
 415         simple_unlock(&global_runq_lock);
 416
 417         return result;
 418 }
 419
 420 static void
 421 sched_proto_processor_queue_shutdown(
 422         processor_t                    processor)
 423 {
 424         /* With a global runqueue, just stop choosing this processor */
 425         (void)processor;
 426 }
 427
 428 static boolean_t
 429 sched_proto_processor_queue_remove(
 430         processor_t                     processor,
 431         thread_t                thread)
 432 {
 433         void *                  rqlock;
 434         run_queue_t             rq;
 435
 436         rqlock = &global_runq_lock;
 437         rq = global_runq;
 438
 439         simple_lock(rqlock, LCK_GRP_NULL);
 440         if (processor == thread->runq) {
 441                 /*
 442                  *      Thread is on a run queue and we have a lock on
 443                  *      that run queue.
 444                  */
 445                 run_queue_remove(rq, thread);
 446         } else {
 447                 /*
 448                  *      The thread left the run queue before we could
 449                  *      lock the run queue.
 450                  */
 451                 assert(thread->runq == PROCESSOR_NULL);
 452                 processor = PROCESSOR_NULL;
 453         }
 454
 455         simple_unlock(rqlock);
 456
 457         return processor != PROCESSOR_NULL;
 458 }
 459
 460 static boolean_t
 461 sched_proto_processor_queue_empty(processor_t           processor __unused)
 462 {
 463         boolean_t result;
 464
 465         result = (global_runq->count == 0);
 466
 467         return result;
 468 }
 469
 470 static boolean_t
 471 sched_proto_processor_queue_has_priority(processor_t            processor __unused,
 472     int                            priority,
 473     boolean_t              gte)
 474 {
 475         boolean_t result;
 476
 477         simple_lock(&global_runq_lock, LCK_GRP_NULL);
 478
 479         if (gte) {
 480                 result = global_runq->highq >= priority;
 481         } else {
 482                 result = global_runq->highq > priority;
 483         }
 484
 485         simple_unlock(&global_runq_lock);
 486
 487         return result;
 488 }
 489
 490 /* Implement sched_preempt_pri in code */
 491 static boolean_t
 492 sched_proto_priority_is_urgent(int priority)
 493 {
 494         if (priority <= BASEPRI_FOREGROUND) {
 495                 return FALSE;
 496         }
 497
 498         if (priority < MINPRI_KERNEL) {
 499                 return TRUE;
 500         }
 501
 502         if (priority >= BASEPRI_PREEMPT) {
 503                 return TRUE;
 504         }
 505
 506         return FALSE;
 507 }
 508
 509 static ast_t
 510 sched_proto_processor_csw_check(processor_t processor)
 511 {
 512         run_queue_t             runq;
 513         int                             count, urgency;
 514
 515         runq = global_runq;
 516         count = runq->count;
 517         urgency = runq->urgency;
 518
 519         if (count > 0) {
 520                 if (urgency > 0) {
 521                         return AST_PREEMPT | AST_URGENT;
 522                 }
 523
 524                 return AST_PREEMPT;
 525         }
 526
 527         if (proto_processor != processor) {
 528                 return AST_PREEMPT;
 529         }
 530
 531         return AST_NONE;
 532 }
 533
 534 static uint32_t
 535 sched_proto_initial_quantum_size(thread_t thread __unused)
 536 {
 537         return proto_quantum;
 538 }
 539
 540 static sched_mode_t
 541 sched_proto_initial_thread_sched_mode(task_t parent_task)
 542 {
 543         if (parent_task == kernel_task) {
 544                 return TH_MODE_FIXED;
 545         } else {
 546                 return TH_MODE_TIMESHARE;
 547         }
 548 }
 549
 550 static boolean_t
 551 sched_proto_can_update_priority(thread_t        thread __unused)
 552 {
 553         return FALSE;
 554 }
 555
 556 static void
 557 sched_proto_update_priority(thread_t    thread __unused)
 558 {
 559 }
 560
 561 static void
 562 sched_proto_lightweight_update_priority(thread_t        thread __unused)
 563 {
 564 }
 565
 566 static void
 567 sched_proto_quantum_expire(thread_t    thread __unused)
 568 {
 569 }
 570
 571 static int
 572 sched_proto_processor_runq_count(processor_t   processor)
 573 {
 574         if (master_processor == processor) {
 575                 return global_runq->count;
 576         } else {
 577                 return 0;
 578         }
 579 }
 580
 581 static uint64_t
 582 sched_proto_processor_runq_stats_count_sum(processor_t   processor)
 583 {
 584         if (master_processor == processor) {
 585                 return global_runq->runq_stats.count_sum;
 586         } else {
 587                 return 0ULL;
 588         }
 589 }
 590
 591 static int
 592 sched_proto_processor_bound_count(__unused processor_t   processor)
 593 {
 594         return 0;
 595 }
 596
 597 static void
 598 sched_proto_thread_update_scan(__unused sched_update_scan_context_t scan_context)
 599 {
 600 }