1 /*- 2 * Copyright (c) 2002-2007, Jeffrey Roberson <jeff@freebsd.org> 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 unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include "opt_hwpmc_hooks.h" 31 #include "opt_sched.h" 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/kdb.h> 36 #include <sys/kernel.h> 37 #include <sys/ktr.h> 38 #include <sys/lock.h> 39 #include <sys/mutex.h> 40 #include <sys/proc.h> 41 #include <sys/resource.h> 42 #include <sys/resourcevar.h> 43 #include <sys/sched.h> 44 #include <sys/smp.h> 45 #include <sys/sx.h> 46 #include <sys/sysctl.h> 47 #include <sys/sysproto.h> 48 #include <sys/turnstile.h> 49 #include <sys/umtx.h> 50 #include <sys/vmmeter.h> 51 #ifdef KTRACE 52 #include <sys/uio.h> 53 #include <sys/ktrace.h> 54 #endif 55 56 #ifdef HWPMC_HOOKS 57 #include <sys/pmckern.h> 58 #endif 59 60 #include <machine/cpu.h> 61 #include <machine/smp.h> 62 63 #ifndef PREEMPTION 64 #error "SCHED_ULE requires options PREEMPTION" 65 #endif 66 67 /* 68 * TODO: 69 * Pick idle from affinity group or self group first. 70 * Implement pick_score. 71 */ 72 73 #define KTR_ULE 0x0 /* Enable for pickpri debugging. */ 74 75 /* 76 * Thread scheduler specific section. 77 */ 78 struct td_sched { 79 TAILQ_ENTRY(td_sched) ts_procq; /* (j/z) Run queue. */ 80 int ts_flags; /* (j) TSF_* flags. */ 81 struct thread *ts_thread; /* (*) Active associated thread. */ 82 u_char ts_rqindex; /* (j) Run queue index. */ 83 int ts_slptime; 84 int ts_slice; 85 struct runq *ts_runq; 86 u_char ts_cpu; /* CPU that we have affinity for. */ 87 /* The following variables are only used for pctcpu calculation */ 88 int ts_ltick; /* Last tick that we were running on */ 89 int ts_ftick; /* First tick that we were running on */ 90 int ts_ticks; /* Tick count */ 91 #ifdef SMP 92 int ts_rltick; /* Real last tick, for affinity. */ 93 #endif 94 95 /* originally from kg_sched */ 96 u_int skg_slptime; /* Number of ticks we vol. slept */ 97 u_int skg_runtime; /* Number of ticks we were running */ 98 }; 99 /* flags kept in ts_flags */ 100 #define TSF_BOUND 0x0001 /* Thread can not migrate. */ 101 #define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */ 102 103 static struct td_sched td_sched0; 104 105 /* 106 * Cpu percentage computation macros and defines. 107 * 108 * SCHED_TICK_SECS: Number of seconds to average the cpu usage across. 109 * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across. 110 * SCHED_TICK_MAX: Maximum number of ticks before scaling back. 111 * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results. 112 * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count. 113 * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks. 114 */ 115 #define SCHED_TICK_SECS 10 116 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS) 117 #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz) 118 #define SCHED_TICK_SHIFT 10 119 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT) 120 #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz)) 121 122 /* 123 * These macros determine priorities for non-interactive threads. They are 124 * assigned a priority based on their recent cpu utilization as expressed 125 * by the ratio of ticks to the tick total. NHALF priorities at the start 126 * and end of the MIN to MAX timeshare range are only reachable with negative 127 * or positive nice respectively. 128 * 129 * PRI_RANGE: Priority range for utilization dependent priorities. 130 * PRI_NRESV: Number of nice values. 131 * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total. 132 * PRI_NICE: Determines the part of the priority inherited from nice. 133 */ 134 #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN) 135 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) 136 #define SCHED_PRI_MIN (PRI_MIN_TIMESHARE + SCHED_PRI_NHALF) 137 #define SCHED_PRI_MAX (PRI_MAX_TIMESHARE - SCHED_PRI_NHALF) 138 #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN + 1) 139 #define SCHED_PRI_TICKS(ts) \ 140 (SCHED_TICK_HZ((ts)) / \ 141 (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE)) 142 #define SCHED_PRI_NICE(nice) (nice) 143 144 /* 145 * These determine the interactivity of a process. Interactivity differs from 146 * cpu utilization in that it expresses the voluntary time slept vs time ran 147 * while cpu utilization includes all time not running. This more accurately 148 * models the intent of the thread. 149 * 150 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 151 * before throttling back. 152 * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time. 153 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 154 * INTERACT_THRESH: Threshhold for placement on the current runq. 155 */ 156 #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT) 157 #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT) 158 #define SCHED_INTERACT_MAX (100) 159 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 160 #define SCHED_INTERACT_THRESH (30) 161 162 /* 163 * tickincr: Converts a stathz tick into a hz domain scaled by 164 * the shift factor. Without the shift the error rate 165 * due to rounding would be unacceptably high. 166 * realstathz: stathz is sometimes 0 and run off of hz. 167 * sched_slice: Runtime of each thread before rescheduling. 168 */ 169 static int sched_interact = SCHED_INTERACT_THRESH; 170 static int realstathz; 171 static int tickincr; 172 static int sched_slice; 173 174 /* 175 * tdq - per processor runqs and statistics. 176 */ 177 struct tdq { 178 struct runq tdq_idle; /* Queue of IDLE threads. */ 179 struct runq tdq_timeshare; /* timeshare run queue. */ 180 struct runq tdq_realtime; /* real-time run queue. */ 181 u_char tdq_idx; /* Current insert index. */ 182 u_char tdq_ridx; /* Current removal index. */ 183 short tdq_flags; /* Thread queue flags */ 184 int tdq_load; /* Aggregate load. */ 185 #ifdef SMP 186 int tdq_transferable; 187 LIST_ENTRY(tdq) tdq_siblings; /* Next in tdq group. */ 188 struct tdq_group *tdq_group; /* Our processor group. */ 189 #else 190 int tdq_sysload; /* For loadavg, !ITHD load. */ 191 #endif 192 }; 193 194 #define TDQF_BUSY 0x0001 /* Queue is marked as busy */ 195 196 #ifdef SMP 197 /* 198 * tdq groups are groups of processors which can cheaply share threads. When 199 * one processor in the group goes idle it will check the runqs of the other 200 * processors in its group prior to halting and waiting for an interrupt. 201 * These groups are suitable for SMT (Symetric Multi-Threading) and not NUMA. 202 * In a numa environment we'd want an idle bitmap per group and a two tiered 203 * load balancer. 204 */ 205 struct tdq_group { 206 int tdg_cpus; /* Count of CPUs in this tdq group. */ 207 cpumask_t tdg_cpumask; /* Mask of cpus in this group. */ 208 cpumask_t tdg_idlemask; /* Idle cpus in this group. */ 209 cpumask_t tdg_mask; /* Bit mask for first cpu. */ 210 int tdg_load; /* Total load of this group. */ 211 int tdg_transferable; /* Transferable load of this group. */ 212 LIST_HEAD(, tdq) tdg_members; /* Linked list of all members. */ 213 }; 214 215 #define SCHED_AFFINITY_DEFAULT (hz / 100) 216 #define SCHED_AFFINITY(ts) ((ts)->ts_rltick > ticks - affinity) 217 218 /* 219 * Run-time tunables. 220 */ 221 static int rebalance = 0; 222 static int pick_pri = 0; 223 static int affinity; 224 static int tryself = 1; 225 static int tryselfidle = 1; 226 static int ipi_ast = 0; 227 static int ipi_preempt = 1; 228 static int ipi_thresh = PRI_MIN_KERN; 229 static int steal_htt = 1; 230 static int steal_busy = 1; 231 static int busy_thresh = 4; 232 static int topology = 0; 233 234 /* 235 * One thread queue per processor. 236 */ 237 static volatile cpumask_t tdq_idle; 238 static volatile cpumask_t tdq_busy; 239 static int tdg_maxid; 240 static struct tdq tdq_cpu[MAXCPU]; 241 static struct tdq_group tdq_groups[MAXCPU]; 242 static int bal_tick; 243 static int gbal_tick; 244 static int balance_groups; 245 246 #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)]) 247 #define TDQ_CPU(x) (&tdq_cpu[(x)]) 248 #define TDQ_ID(x) ((x) - tdq_cpu) 249 #define TDQ_GROUP(x) (&tdq_groups[(x)]) 250 #else /* !SMP */ 251 static struct tdq tdq_cpu; 252 253 #define TDQ_ID(x) (0) 254 #define TDQ_SELF() (&tdq_cpu) 255 #define TDQ_CPU(x) (&tdq_cpu) 256 #endif 257 258 static void sched_priority(struct thread *); 259 static void sched_thread_priority(struct thread *, u_char); 260 static int sched_interact_score(struct thread *); 261 static void sched_interact_update(struct thread *); 262 static void sched_interact_fork(struct thread *); 263 static void sched_pctcpu_update(struct td_sched *); 264 static inline void sched_pin_td(struct thread *td); 265 static inline void sched_unpin_td(struct thread *td); 266 267 /* Operations on per processor queues */ 268 static struct td_sched * tdq_choose(struct tdq *); 269 static void tdq_setup(struct tdq *); 270 static void tdq_load_add(struct tdq *, struct td_sched *); 271 static void tdq_load_rem(struct tdq *, struct td_sched *); 272 static __inline void tdq_runq_add(struct tdq *, struct td_sched *, int); 273 static __inline void tdq_runq_rem(struct tdq *, struct td_sched *); 274 void tdq_print(int cpu); 275 static void runq_print(struct runq *rq); 276 #ifdef SMP 277 static int tdq_pickidle(struct tdq *, struct td_sched *); 278 static int tdq_pickpri(struct tdq *, struct td_sched *, int); 279 static struct td_sched *runq_steal(struct runq *); 280 static void sched_balance(void); 281 static void sched_balance_groups(void); 282 static void sched_balance_group(struct tdq_group *); 283 static void sched_balance_pair(struct tdq *, struct tdq *); 284 static void sched_smp_tick(struct thread *); 285 static void tdq_move(struct tdq *, int); 286 static int tdq_idled(struct tdq *); 287 static void tdq_notify(struct td_sched *); 288 static struct td_sched *tdq_steal(struct tdq *, int); 289 290 #define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0) 291 #endif 292 293 static void sched_setup(void *dummy); 294 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL) 295 296 static void sched_initticks(void *dummy); 297 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, NULL) 298 299 static inline void 300 sched_pin_td(struct thread *td) 301 { 302 td->td_pinned++; 303 } 304 305 static inline void 306 sched_unpin_td(struct thread *td) 307 { 308 td->td_pinned--; 309 } 310 311 static void 312 runq_print(struct runq *rq) 313 { 314 struct rqhead *rqh; 315 struct td_sched *ts; 316 int pri; 317 int j; 318 int i; 319 320 for (i = 0; i < RQB_LEN; i++) { 321 printf("\t\trunq bits %d 0x%zx\n", 322 i, rq->rq_status.rqb_bits[i]); 323 for (j = 0; j < RQB_BPW; j++) 324 if (rq->rq_status.rqb_bits[i] & (1ul << j)) { 325 pri = j + (i << RQB_L2BPW); 326 rqh = &rq->rq_queues[pri]; 327 TAILQ_FOREACH(ts, rqh, ts_procq) { 328 printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n", 329 ts->ts_thread, ts->ts_thread->td_proc->p_comm, ts->ts_thread->td_priority, ts->ts_rqindex, pri); 330 } 331 } 332 } 333 } 334 335 void 336 tdq_print(int cpu) 337 { 338 struct tdq *tdq; 339 340 tdq = TDQ_CPU(cpu); 341 342 printf("tdq:\n"); 343 printf("\tload: %d\n", tdq->tdq_load); 344 printf("\ttimeshare idx: %d\n", tdq->tdq_idx); 345 printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx); 346 printf("\trealtime runq:\n"); 347 runq_print(&tdq->tdq_realtime); 348 printf("\ttimeshare runq:\n"); 349 runq_print(&tdq->tdq_timeshare); 350 printf("\tidle runq:\n"); 351 runq_print(&tdq->tdq_idle); 352 #ifdef SMP 353 printf("\tload transferable: %d\n", tdq->tdq_transferable); 354 #endif 355 } 356 357 static __inline void 358 tdq_runq_add(struct tdq *tdq, struct td_sched *ts, int flags) 359 { 360 #ifdef SMP 361 if (THREAD_CAN_MIGRATE(ts->ts_thread)) { 362 tdq->tdq_transferable++; 363 tdq->tdq_group->tdg_transferable++; 364 ts->ts_flags |= TSF_XFERABLE; 365 if (tdq->tdq_transferable >= busy_thresh && 366 (tdq->tdq_flags & TDQF_BUSY) == 0) { 367 tdq->tdq_flags |= TDQF_BUSY; 368 atomic_set_int(&tdq_busy, 1 << TDQ_ID(tdq)); 369 } 370 } 371 #endif 372 if (ts->ts_runq == &tdq->tdq_timeshare) { 373 u_char pri; 374 375 pri = ts->ts_thread->td_priority; 376 KASSERT(pri <= PRI_MAX_TIMESHARE && pri >= PRI_MIN_TIMESHARE, 377 ("Invalid priority %d on timeshare runq", pri)); 378 /* 379 * This queue contains only priorities between MIN and MAX 380 * realtime. Use the whole queue to represent these values. 381 */ 382 #define TS_RQ_PPQ (((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) + 1) / RQ_NQS) 383 if ((flags & SRQ_BORROWING) == 0) { 384 pri = (pri - PRI_MIN_TIMESHARE) / TS_RQ_PPQ; 385 pri = (pri + tdq->tdq_idx) % RQ_NQS; 386 /* 387 * This effectively shortens the queue by one so we 388 * can have a one slot difference between idx and 389 * ridx while we wait for threads to drain. 390 */ 391 if (tdq->tdq_ridx != tdq->tdq_idx && 392 pri == tdq->tdq_ridx) 393 pri = (unsigned char)(pri - 1) % RQ_NQS; 394 } else 395 pri = tdq->tdq_ridx; 396 runq_add_pri(ts->ts_runq, ts, pri, flags); 397 } else 398 runq_add(ts->ts_runq, ts, flags); 399 } 400 401 static __inline void 402 tdq_runq_rem(struct tdq *tdq, struct td_sched *ts) 403 { 404 #ifdef SMP 405 if (ts->ts_flags & TSF_XFERABLE) { 406 tdq->tdq_transferable--; 407 tdq->tdq_group->tdg_transferable--; 408 ts->ts_flags &= ~TSF_XFERABLE; 409 if (tdq->tdq_transferable < busy_thresh && 410 (tdq->tdq_flags & TDQF_BUSY)) { 411 atomic_clear_int(&tdq_busy, 1 << TDQ_ID(tdq)); 412 tdq->tdq_flags &= ~TDQF_BUSY; 413 } 414 } 415 #endif 416 if (ts->ts_runq == &tdq->tdq_timeshare) { 417 if (tdq->tdq_idx != tdq->tdq_ridx) 418 runq_remove_idx(ts->ts_runq, ts, &tdq->tdq_ridx); 419 else 420 runq_remove_idx(ts->ts_runq, ts, NULL); 421 /* 422 * For timeshare threads we update the priority here so 423 * the priority reflects the time we've been sleeping. 424 */ 425 ts->ts_ltick = ticks; 426 sched_pctcpu_update(ts); 427 sched_priority(ts->ts_thread); 428 } else 429 runq_remove(ts->ts_runq, ts); 430 } 431 432 static void 433 tdq_load_add(struct tdq *tdq, struct td_sched *ts) 434 { 435 int class; 436 mtx_assert(&sched_lock, MA_OWNED); 437 class = PRI_BASE(ts->ts_thread->td_pri_class); 438 tdq->tdq_load++; 439 CTR2(KTR_SCHED, "cpu %jd load: %d", TDQ_ID(tdq), tdq->tdq_load); 440 if (class != PRI_ITHD && 441 (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0) 442 #ifdef SMP 443 tdq->tdq_group->tdg_load++; 444 #else 445 tdq->tdq_sysload++; 446 #endif 447 } 448 449 static void 450 tdq_load_rem(struct tdq *tdq, struct td_sched *ts) 451 { 452 int class; 453 mtx_assert(&sched_lock, MA_OWNED); 454 class = PRI_BASE(ts->ts_thread->td_pri_class); 455 if (class != PRI_ITHD && 456 (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0) 457 #ifdef SMP 458 tdq->tdq_group->tdg_load--; 459 #else 460 tdq->tdq_sysload--; 461 #endif 462 tdq->tdq_load--; 463 CTR1(KTR_SCHED, "load: %d", tdq->tdq_load); 464 ts->ts_runq = NULL; 465 } 466 467 #ifdef SMP 468 static void 469 sched_smp_tick(struct thread *td) 470 { 471 struct tdq *tdq; 472 473 tdq = TDQ_SELF(); 474 if (rebalance) { 475 if (ticks >= bal_tick) 476 sched_balance(); 477 if (ticks >= gbal_tick && balance_groups) 478 sched_balance_groups(); 479 } 480 td->td_sched->ts_rltick = ticks; 481 } 482 483 /* 484 * sched_balance is a simple CPU load balancing algorithm. It operates by 485 * finding the least loaded and most loaded cpu and equalizing their load 486 * by migrating some processes. 487 * 488 * Dealing only with two CPUs at a time has two advantages. Firstly, most 489 * installations will only have 2 cpus. Secondly, load balancing too much at 490 * once can have an unpleasant effect on the system. The scheduler rarely has 491 * enough information to make perfect decisions. So this algorithm chooses 492 * algorithm simplicity and more gradual effects on load in larger systems. 493 * 494 * It could be improved by considering the priorities and slices assigned to 495 * each task prior to balancing them. There are many pathological cases with 496 * any approach and so the semi random algorithm below may work as well as any. 497 * 498 */ 499 static void 500 sched_balance(void) 501 { 502 struct tdq_group *high; 503 struct tdq_group *low; 504 struct tdq_group *tdg; 505 int cnt; 506 int i; 507 508 bal_tick = ticks + (random() % (hz * 2)); 509 if (smp_started == 0) 510 return; 511 low = high = NULL; 512 i = random() % (tdg_maxid + 1); 513 for (cnt = 0; cnt <= tdg_maxid; cnt++) { 514 tdg = TDQ_GROUP(i); 515 /* 516 * Find the CPU with the highest load that has some 517 * threads to transfer. 518 */ 519 if ((high == NULL || tdg->tdg_load > high->tdg_load) 520 && tdg->tdg_transferable) 521 high = tdg; 522 if (low == NULL || tdg->tdg_load < low->tdg_load) 523 low = tdg; 524 if (++i > tdg_maxid) 525 i = 0; 526 } 527 if (low != NULL && high != NULL && high != low) 528 sched_balance_pair(LIST_FIRST(&high->tdg_members), 529 LIST_FIRST(&low->tdg_members)); 530 } 531 532 static void 533 sched_balance_groups(void) 534 { 535 int i; 536 537 gbal_tick = ticks + (random() % (hz * 2)); 538 mtx_assert(&sched_lock, MA_OWNED); 539 if (smp_started) 540 for (i = 0; i <= tdg_maxid; i++) 541 sched_balance_group(TDQ_GROUP(i)); 542 } 543 544 static void 545 sched_balance_group(struct tdq_group *tdg) 546 { 547 struct tdq *tdq; 548 struct tdq *high; 549 struct tdq *low; 550 int load; 551 552 if (tdg->tdg_transferable == 0) 553 return; 554 low = NULL; 555 high = NULL; 556 LIST_FOREACH(tdq, &tdg->tdg_members, tdq_siblings) { 557 load = tdq->tdq_load; 558 if (high == NULL || load > high->tdq_load) 559 high = tdq; 560 if (low == NULL || load < low->tdq_load) 561 low = tdq; 562 } 563 if (high != NULL && low != NULL && high != low) 564 sched_balance_pair(high, low); 565 } 566 567 static void 568 sched_balance_pair(struct tdq *high, struct tdq *low) 569 { 570 int transferable; 571 int high_load; 572 int low_load; 573 int move; 574 int diff; 575 int i; 576 577 /* 578 * If we're transfering within a group we have to use this specific 579 * tdq's transferable count, otherwise we can steal from other members 580 * of the group. 581 */ 582 if (high->tdq_group == low->tdq_group) { 583 transferable = high->tdq_transferable; 584 high_load = high->tdq_load; 585 low_load = low->tdq_load; 586 } else { 587 transferable = high->tdq_group->tdg_transferable; 588 high_load = high->tdq_group->tdg_load; 589 low_load = low->tdq_group->tdg_load; 590 } 591 if (transferable == 0) 592 return; 593 /* 594 * Determine what the imbalance is and then adjust that to how many 595 * threads we actually have to give up (transferable). 596 */ 597 diff = high_load - low_load; 598 move = diff / 2; 599 if (diff & 0x1) 600 move++; 601 move = min(move, transferable); 602 for (i = 0; i < move; i++) 603 tdq_move(high, TDQ_ID(low)); 604 return; 605 } 606 607 static void 608 tdq_move(struct tdq *from, int cpu) 609 { 610 struct tdq *tdq; 611 struct tdq *to; 612 struct td_sched *ts; 613 614 tdq = from; 615 to = TDQ_CPU(cpu); 616 ts = tdq_steal(tdq, 1); 617 if (ts == NULL) { 618 struct tdq_group *tdg; 619 620 tdg = tdq->tdq_group; 621 LIST_FOREACH(tdq, &tdg->tdg_members, tdq_siblings) { 622 if (tdq == from || tdq->tdq_transferable == 0) 623 continue; 624 ts = tdq_steal(tdq, 1); 625 break; 626 } 627 if (ts == NULL) 628 panic("tdq_move: No threads available with a " 629 "transferable count of %d\n", 630 tdg->tdg_transferable); 631 } 632 if (tdq == to) 633 return; 634 sched_rem(ts->ts_thread); 635 ts->ts_cpu = cpu; 636 sched_pin_td(ts->ts_thread); 637 sched_add(ts->ts_thread, SRQ_YIELDING); 638 sched_unpin_td(ts->ts_thread); 639 } 640 641 static int 642 tdq_idled(struct tdq *tdq) 643 { 644 struct tdq_group *tdg; 645 struct tdq *steal; 646 struct td_sched *ts; 647 648 tdg = tdq->tdq_group; 649 /* 650 * If we're in a cpu group, try and steal threads from another cpu in 651 * the group before idling. 652 */ 653 if (steal_htt && tdg->tdg_cpus > 1 && tdg->tdg_transferable) { 654 LIST_FOREACH(steal, &tdg->tdg_members, tdq_siblings) { 655 if (steal == tdq || steal->tdq_transferable == 0) 656 continue; 657 ts = tdq_steal(steal, 0); 658 if (ts) 659 goto steal; 660 } 661 } 662 if (steal_busy) { 663 while (tdq_busy) { 664 int cpu; 665 666 cpu = ffs(tdq_busy); 667 if (cpu == 0) 668 break; 669 cpu--; 670 steal = TDQ_CPU(cpu); 671 if (steal->tdq_transferable == 0) 672 continue; 673 ts = tdq_steal(steal, 1); 674 if (ts == NULL) 675 continue; 676 CTR5(KTR_ULE, 677 "tdq_idled: stealing td %p(%s) pri %d from %d busy 0x%X", 678 ts->ts_thread, ts->ts_thread->td_proc->p_comm, 679 ts->ts_thread->td_priority, cpu, tdq_busy); 680 goto steal; 681 } 682 } 683 /* 684 * We only set the idled bit when all of the cpus in the group are 685 * idle. Otherwise we could get into a situation where a thread bounces 686 * back and forth between two idle cores on seperate physical CPUs. 687 */ 688 tdg->tdg_idlemask |= PCPU_GET(cpumask); 689 if (tdg->tdg_idlemask == tdg->tdg_cpumask) 690 atomic_set_int(&tdq_idle, tdg->tdg_mask); 691 return (1); 692 steal: 693 sched_rem(ts->ts_thread); 694 ts->ts_cpu = PCPU_GET(cpuid); 695 sched_pin_td(ts->ts_thread); 696 sched_add(ts->ts_thread, SRQ_YIELDING); 697 sched_unpin_td(ts->ts_thread); 698 699 return (0); 700 } 701 702 static void 703 tdq_notify(struct td_sched *ts) 704 { 705 struct thread *ctd; 706 struct pcpu *pcpu; 707 int cpri; 708 int pri; 709 int cpu; 710 711 cpu = ts->ts_cpu; 712 pri = ts->ts_thread->td_priority; 713 pcpu = pcpu_find(cpu); 714 ctd = pcpu->pc_curthread; 715 cpri = ctd->td_priority; 716 717 /* 718 * If our priority is not better than the current priority there is 719 * nothing to do. 720 */ 721 if (pri > cpri) 722 return; 723 /* 724 * Always IPI idle. 725 */ 726 if (cpri > PRI_MIN_IDLE) 727 goto sendipi; 728 /* 729 * If we're realtime or better and there is timeshare or worse running 730 * send an IPI. 731 */ 732 if (pri < PRI_MAX_REALTIME && cpri > PRI_MAX_REALTIME) 733 goto sendipi; 734 /* 735 * Otherwise only IPI if we exceed the threshold. 736 */ 737 if (pri > ipi_thresh) 738 return; 739 sendipi: 740 ctd->td_flags |= TDF_NEEDRESCHED; 741 if (cpri < PRI_MIN_IDLE) { 742 if (ipi_ast) 743 ipi_selected(1 << cpu, IPI_AST); 744 else if (ipi_preempt) 745 ipi_selected(1 << cpu, IPI_PREEMPT); 746 } else 747 ipi_selected(1 << cpu, IPI_PREEMPT); 748 } 749 750 static struct td_sched * 751 runq_steal(struct runq *rq) 752 { 753 struct rqhead *rqh; 754 struct rqbits *rqb; 755 struct td_sched *ts; 756 int word; 757 int bit; 758 759 mtx_assert(&sched_lock, MA_OWNED); 760 rqb = &rq->rq_status; 761 for (word = 0; word < RQB_LEN; word++) { 762 if (rqb->rqb_bits[word] == 0) 763 continue; 764 for (bit = 0; bit < RQB_BPW; bit++) { 765 if ((rqb->rqb_bits[word] & (1ul << bit)) == 0) 766 continue; 767 rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; 768 TAILQ_FOREACH(ts, rqh, ts_procq) { 769 if (THREAD_CAN_MIGRATE(ts->ts_thread)) 770 return (ts); 771 } 772 } 773 } 774 return (NULL); 775 } 776 777 static struct td_sched * 778 tdq_steal(struct tdq *tdq, int stealidle) 779 { 780 struct td_sched *ts; 781 782 /* 783 * Steal from next first to try to get a non-interactive task that 784 * may not have run for a while. 785 * XXX Need to effect steal order for timeshare threads. 786 */ 787 if ((ts = runq_steal(&tdq->tdq_realtime)) != NULL) 788 return (ts); 789 if ((ts = runq_steal(&tdq->tdq_timeshare)) != NULL) 790 return (ts); 791 if (stealidle) 792 return (runq_steal(&tdq->tdq_idle)); 793 return (NULL); 794 } 795 796 int 797 tdq_pickidle(struct tdq *tdq, struct td_sched *ts) 798 { 799 struct tdq_group *tdg; 800 int self; 801 int cpu; 802 803 self = PCPU_GET(cpuid); 804 if (smp_started == 0) 805 return (self); 806 /* 807 * If the current CPU has idled, just run it here. 808 */ 809 if ((tdq->tdq_group->tdg_idlemask & PCPU_GET(cpumask)) != 0) 810 return (self); 811 /* 812 * Try the last group we ran on. 813 */ 814 tdg = TDQ_CPU(ts->ts_cpu)->tdq_group; 815 cpu = ffs(tdg->tdg_idlemask); 816 if (cpu) 817 return (cpu - 1); 818 /* 819 * Search for an idle group. 820 */ 821 cpu = ffs(tdq_idle); 822 if (cpu) 823 return (cpu - 1); 824 /* 825 * XXX If there are no idle groups, check for an idle core. 826 */ 827 /* 828 * No idle CPUs? 829 */ 830 return (self); 831 } 832 833 static int 834 tdq_pickpri(struct tdq *tdq, struct td_sched *ts, int flags) 835 { 836 struct pcpu *pcpu; 837 int lowpri; 838 int lowcpu; 839 int lowload; 840 int load; 841 int self; 842 int pri; 843 int cpu; 844 845 self = PCPU_GET(cpuid); 846 if (smp_started == 0) 847 return (self); 848 849 pri = ts->ts_thread->td_priority; 850 /* 851 * Regardless of affinity, if the last cpu is idle send it there. 852 */ 853 pcpu = pcpu_find(ts->ts_cpu); 854 if (pcpu->pc_curthread->td_priority > PRI_MIN_IDLE) { 855 CTR5(KTR_ULE, 856 "ts_cpu %d idle, ltick %d ticks %d pri %d curthread %d", 857 ts->ts_cpu, ts->ts_rltick, ticks, pri, 858 pcpu->pc_curthread->td_priority); 859 return (ts->ts_cpu); 860 } 861 /* 862 * If we have affinity, try to place it on the cpu we last ran on. 863 */ 864 if (SCHED_AFFINITY(ts) && pcpu->pc_curthread->td_priority > pri) { 865 CTR5(KTR_ULE, 866 "affinity for %d, ltick %d ticks %d pri %d curthread %d", 867 ts->ts_cpu, ts->ts_rltick, ticks, pri, 868 pcpu->pc_curthread->td_priority); 869 return (ts->ts_cpu); 870 } 871 /* 872 * Try ourself first; If we're running something lower priority this 873 * may have some locality with the waking thread and execute faster 874 * here. 875 */ 876 if (tryself) { 877 /* 878 * If we're being awoken by an interrupt thread or the waker 879 * is going right to sleep run here as well. 880 */ 881 if ((TDQ_SELF()->tdq_load == 1) && (flags & SRQ_YIELDING || 882 curthread->td_pri_class == PRI_ITHD)) { 883 CTR2(KTR_ULE, "tryself load %d flags %d", 884 TDQ_SELF()->tdq_load, flags); 885 return (self); 886 } 887 } 888 /* 889 * Look for an idle group. 890 */ 891 CTR1(KTR_ULE, "tdq_idle %X", tdq_idle); 892 cpu = ffs(tdq_idle); 893 if (cpu) 894 return (cpu - 1); 895 if (tryselfidle && pri < curthread->td_priority) { 896 CTR1(KTR_ULE, "tryself %d", 897 curthread->td_priority); 898 return (self); 899 } 900 /* 901 * Now search for the cpu running the lowest priority thread with 902 * the least load. 903 */ 904 lowload = 0; 905 lowpri = lowcpu = 0; 906 for (cpu = 0; cpu <= mp_maxid; cpu++) { 907 if (CPU_ABSENT(cpu)) 908 continue; 909 pcpu = pcpu_find(cpu); 910 pri = pcpu->pc_curthread->td_priority; 911 CTR4(KTR_ULE, 912 "cpu %d pri %d lowcpu %d lowpri %d", 913 cpu, pri, lowcpu, lowpri); 914 if (pri < lowpri) 915 continue; 916 load = TDQ_CPU(cpu)->tdq_load; 917 if (lowpri && lowpri == pri && load > lowload) 918 continue; 919 lowpri = pri; 920 lowcpu = cpu; 921 lowload = load; 922 } 923 924 return (lowcpu); 925 } 926 927 #endif /* SMP */ 928 929 /* 930 * Pick the highest priority task we have and return it. 931 */ 932 933 static struct td_sched * 934 tdq_choose(struct tdq *tdq) 935 { 936 struct td_sched *ts; 937 938 mtx_assert(&sched_lock, MA_OWNED); 939 940 ts = runq_choose(&tdq->tdq_realtime); 941 if (ts != NULL) { 942 KASSERT(ts->ts_thread->td_priority <= PRI_MAX_REALTIME, 943 ("tdq_choose: Invalid priority on realtime queue %d", 944 ts->ts_thread->td_priority)); 945 return (ts); 946 } 947 ts = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx); 948 if (ts != NULL) { 949 KASSERT(ts->ts_thread->td_priority <= PRI_MAX_TIMESHARE && 950 ts->ts_thread->td_priority >= PRI_MIN_TIMESHARE, 951 ("tdq_choose: Invalid priority on timeshare queue %d", 952 ts->ts_thread->td_priority)); 953 return (ts); 954 } 955 956 ts = runq_choose(&tdq->tdq_idle); 957 if (ts != NULL) { 958 KASSERT(ts->ts_thread->td_priority >= PRI_MIN_IDLE, 959 ("tdq_choose: Invalid priority on idle queue %d", 960 ts->ts_thread->td_priority)); 961 return (ts); 962 } 963 964 return (NULL); 965 } 966 967 static void 968 tdq_setup(struct tdq *tdq) 969 { 970 runq_init(&tdq->tdq_realtime); 971 runq_init(&tdq->tdq_timeshare); 972 runq_init(&tdq->tdq_idle); 973 tdq->tdq_load = 0; 974 } 975 976 static void 977 sched_setup(void *dummy) 978 { 979 #ifdef SMP 980 int i; 981 #endif 982 983 /* 984 * To avoid divide-by-zero, we set realstathz a dummy value 985 * in case which sched_clock() called before sched_initticks(). 986 */ 987 realstathz = hz; 988 sched_slice = (realstathz/10); /* ~100ms */ 989 tickincr = 1 << SCHED_TICK_SHIFT; 990 991 #ifdef SMP 992 balance_groups = 0; 993 /* 994 * Initialize the tdqs. 995 */ 996 for (i = 0; i < MAXCPU; i++) { 997 struct tdq *tdq; 998 999 tdq = &tdq_cpu[i]; 1000 tdq_setup(&tdq_cpu[i]); 1001 } 1002 if (smp_topology == NULL) { 1003 struct tdq_group *tdg; 1004 struct tdq *tdq; 1005 int cpus; 1006 1007 for (cpus = 0, i = 0; i < MAXCPU; i++) { 1008 if (CPU_ABSENT(i)) 1009 continue; 1010 tdq = &tdq_cpu[i]; 1011 tdg = &tdq_groups[cpus]; 1012 /* 1013 * Setup a tdq group with one member. 1014 */ 1015 tdq->tdq_transferable = 0; 1016 tdq->tdq_group = tdg; 1017 tdg->tdg_cpus = 1; 1018 tdg->tdg_idlemask = 0; 1019 tdg->tdg_cpumask = tdg->tdg_mask = 1 << i; 1020 tdg->tdg_load = 0; 1021 tdg->tdg_transferable = 0; 1022 LIST_INIT(&tdg->tdg_members); 1023 LIST_INSERT_HEAD(&tdg->tdg_members, tdq, tdq_siblings); 1024 cpus++; 1025 } 1026 tdg_maxid = cpus - 1; 1027 } else { 1028 struct tdq_group *tdg; 1029 struct cpu_group *cg; 1030 int j; 1031 1032 topology = 1; 1033 for (i = 0; i < smp_topology->ct_count; i++) { 1034 cg = &smp_topology->ct_group[i]; 1035 tdg = &tdq_groups[i]; 1036 /* 1037 * Initialize the group. 1038 */ 1039 tdg->tdg_idlemask = 0; 1040 tdg->tdg_load = 0; 1041 tdg->tdg_transferable = 0; 1042 tdg->tdg_cpus = cg->cg_count; 1043 tdg->tdg_cpumask = cg->cg_mask; 1044 LIST_INIT(&tdg->tdg_members); 1045 /* 1046 * Find all of the group members and add them. 1047 */ 1048 for (j = 0; j < MAXCPU; j++) { 1049 if ((cg->cg_mask & (1 << j)) != 0) { 1050 if (tdg->tdg_mask == 0) 1051 tdg->tdg_mask = 1 << j; 1052 tdq_cpu[j].tdq_transferable = 0; 1053 tdq_cpu[j].tdq_group = tdg; 1054 LIST_INSERT_HEAD(&tdg->tdg_members, 1055 &tdq_cpu[j], tdq_siblings); 1056 } 1057 } 1058 if (tdg->tdg_cpus > 1) 1059 balance_groups = 1; 1060 } 1061 tdg_maxid = smp_topology->ct_count - 1; 1062 } 1063 /* 1064 * Stagger the group and global load balancer so they do not 1065 * interfere with each other. 1066 */ 1067 bal_tick = ticks + hz; 1068 if (balance_groups) 1069 gbal_tick = ticks + (hz / 2); 1070 #else 1071 tdq_setup(TDQ_SELF()); 1072 #endif 1073 mtx_lock_spin(&sched_lock); 1074 tdq_load_add(TDQ_SELF(), &td_sched0); 1075 mtx_unlock_spin(&sched_lock); 1076 } 1077 1078 /* ARGSUSED */ 1079 static void 1080 sched_initticks(void *dummy) 1081 { 1082 mtx_lock_spin(&sched_lock); 1083 realstathz = stathz ? stathz : hz; 1084 sched_slice = (realstathz/10); /* ~100ms */ 1085 1086 /* 1087 * tickincr is shifted out by 10 to avoid rounding errors due to 1088 * hz not being evenly divisible by stathz on all platforms. 1089 */ 1090 tickincr = (hz << SCHED_TICK_SHIFT) / realstathz; 1091 /* 1092 * This does not work for values of stathz that are more than 1093 * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen. 1094 */ 1095 if (tickincr == 0) 1096 tickincr = 1; 1097 #ifdef SMP 1098 affinity = SCHED_AFFINITY_DEFAULT; 1099 #endif 1100 mtx_unlock_spin(&sched_lock); 1101 } 1102 1103 1104 /* 1105 * Scale the scheduling priority according to the "interactivity" of this 1106 * process. 1107 */ 1108 static void 1109 sched_priority(struct thread *td) 1110 { 1111 int score; 1112 int pri; 1113 1114 if (td->td_pri_class != PRI_TIMESHARE) 1115 return; 1116 /* 1117 * If the score is interactive we place the thread in the realtime 1118 * queue with a priority that is less than kernel and interrupt 1119 * priorities. These threads are not subject to nice restrictions. 1120 * 1121 * Scores greater than this are placed on the normal realtime queue 1122 * where the priority is partially decided by the most recent cpu 1123 * utilization and the rest is decided by nice value. 1124 */ 1125 score = sched_interact_score(td); 1126 if (score < sched_interact) { 1127 pri = PRI_MIN_REALTIME; 1128 pri += ((PRI_MAX_REALTIME - PRI_MIN_REALTIME) / sched_interact) 1129 * score; 1130 KASSERT(pri >= PRI_MIN_REALTIME && pri <= PRI_MAX_REALTIME, 1131 ("sched_priority: invalid interactive priority %d score %d", 1132 pri, score)); 1133 } else { 1134 pri = SCHED_PRI_MIN; 1135 if (td->td_sched->ts_ticks) 1136 pri += SCHED_PRI_TICKS(td->td_sched); 1137 pri += SCHED_PRI_NICE(td->td_proc->p_nice); 1138 if (!(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE)) { 1139 static int once = 1; 1140 if (once) { 1141 printf("sched_priority: invalid priority %d", 1142 pri); 1143 printf("nice %d, ticks %d ftick %d ltick %d tick pri %d\n", 1144 td->td_proc->p_nice, 1145 td->td_sched->ts_ticks, 1146 td->td_sched->ts_ftick, 1147 td->td_sched->ts_ltick, 1148 SCHED_PRI_TICKS(td->td_sched)); 1149 once = 0; 1150 } 1151 pri = min(max(pri, PRI_MIN_TIMESHARE), 1152 PRI_MAX_TIMESHARE); 1153 } 1154 } 1155 sched_user_prio(td, pri); 1156 1157 return; 1158 } 1159 1160 /* 1161 * This routine enforces a maximum limit on the amount of scheduling history 1162 * kept. It is called after either the slptime or runtime is adjusted. 1163 */ 1164 static void 1165 sched_interact_update(struct thread *td) 1166 { 1167 struct td_sched *ts; 1168 u_int sum; 1169 1170 ts = td->td_sched; 1171 sum = ts->skg_runtime + ts->skg_slptime; 1172 if (sum < SCHED_SLP_RUN_MAX) 1173 return; 1174 /* 1175 * This only happens from two places: 1176 * 1) We have added an unusual amount of run time from fork_exit. 1177 * 2) We have added an unusual amount of sleep time from sched_sleep(). 1178 */ 1179 if (sum > SCHED_SLP_RUN_MAX * 2) { 1180 if (ts->skg_runtime > ts->skg_slptime) { 1181 ts->skg_runtime = SCHED_SLP_RUN_MAX; 1182 ts->skg_slptime = 1; 1183 } else { 1184 ts->skg_slptime = SCHED_SLP_RUN_MAX; 1185 ts->skg_runtime = 1; 1186 } 1187 return; 1188 } 1189 /* 1190 * If we have exceeded by more than 1/5th then the algorithm below 1191 * will not bring us back into range. Dividing by two here forces 1192 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] 1193 */ 1194 if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) { 1195 ts->skg_runtime /= 2; 1196 ts->skg_slptime /= 2; 1197 return; 1198 } 1199 ts->skg_runtime = (ts->skg_runtime / 5) * 4; 1200 ts->skg_slptime = (ts->skg_slptime / 5) * 4; 1201 } 1202 1203 static void 1204 sched_interact_fork(struct thread *td) 1205 { 1206 int ratio; 1207 int sum; 1208 1209 sum = td->td_sched->skg_runtime + td->td_sched->skg_slptime; 1210 if (sum > SCHED_SLP_RUN_FORK) { 1211 ratio = sum / SCHED_SLP_RUN_FORK; 1212 td->td_sched->skg_runtime /= ratio; 1213 td->td_sched->skg_slptime /= ratio; 1214 } 1215 } 1216 1217 static int 1218 sched_interact_score(struct thread *td) 1219 { 1220 int div; 1221 1222 if (td->td_sched->skg_runtime > td->td_sched->skg_slptime) { 1223 div = max(1, td->td_sched->skg_runtime / SCHED_INTERACT_HALF); 1224 return (SCHED_INTERACT_HALF + 1225 (SCHED_INTERACT_HALF - (td->td_sched->skg_slptime / div))); 1226 } 1227 if (td->td_sched->skg_slptime > td->td_sched->skg_runtime) { 1228 div = max(1, td->td_sched->skg_slptime / SCHED_INTERACT_HALF); 1229 return (td->td_sched->skg_runtime / div); 1230 } 1231 /* runtime == slptime */ 1232 if (td->td_sched->skg_runtime) 1233 return (SCHED_INTERACT_HALF); 1234 1235 /* 1236 * This can happen if slptime and runtime are 0. 1237 */ 1238 return (0); 1239 1240 } 1241 1242 /* 1243 * Called from proc0_init() to bootstrap the scheduler. 1244 */ 1245 void 1246 schedinit(void) 1247 { 1248 1249 /* 1250 * Set up the scheduler specific parts of proc0. 1251 */ 1252 proc0.p_sched = NULL; /* XXX */ 1253 thread0.td_sched = &td_sched0; 1254 thread0.td_lock = &sched_lock; 1255 td_sched0.ts_ltick = ticks; 1256 td_sched0.ts_ftick = ticks; 1257 td_sched0.ts_thread = &thread0; 1258 } 1259 1260 /* 1261 * This is only somewhat accurate since given many processes of the same 1262 * priority they will switch when their slices run out, which will be 1263 * at most sched_slice stathz ticks. 1264 */ 1265 int 1266 sched_rr_interval(void) 1267 { 1268 1269 /* Convert sched_slice to hz */ 1270 return (hz/(realstathz/sched_slice)); 1271 } 1272 1273 static void 1274 sched_pctcpu_update(struct td_sched *ts) 1275 { 1276 1277 if (ts->ts_ticks == 0) 1278 return; 1279 if (ticks - (hz / 10) < ts->ts_ltick && 1280 SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX) 1281 return; 1282 /* 1283 * Adjust counters and watermark for pctcpu calc. 1284 */ 1285 if (ts->ts_ltick > ticks - SCHED_TICK_TARG) 1286 ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) * 1287 SCHED_TICK_TARG; 1288 else 1289 ts->ts_ticks = 0; 1290 ts->ts_ltick = ticks; 1291 ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG; 1292 } 1293 1294 static void 1295 sched_thread_priority(struct thread *td, u_char prio) 1296 { 1297 struct td_sched *ts; 1298 1299 CTR6(KTR_SCHED, "sched_prio: %p(%s) prio %d newprio %d by %p(%s)", 1300 td, td->td_proc->p_comm, td->td_priority, prio, curthread, 1301 curthread->td_proc->p_comm); 1302 ts = td->td_sched; 1303 THREAD_LOCK_ASSERT(td, MA_OWNED); 1304 if (td->td_priority == prio) 1305 return; 1306 1307 if (TD_ON_RUNQ(td) && prio < td->td_priority) { 1308 /* 1309 * If the priority has been elevated due to priority 1310 * propagation, we may have to move ourselves to a new 1311 * queue. This could be optimized to not re-add in some 1312 * cases. 1313 */ 1314 MPASS(td->td_lock == &sched_lock); 1315 sched_rem(td); 1316 td->td_priority = prio; 1317 sched_add(td, SRQ_BORROWING|SRQ_OURSELF); 1318 } else 1319 td->td_priority = prio; 1320 } 1321 1322 /* 1323 * Update a thread's priority when it is lent another thread's 1324 * priority. 1325 */ 1326 void 1327 sched_lend_prio(struct thread *td, u_char prio) 1328 { 1329 1330 td->td_flags |= TDF_BORROWING; 1331 sched_thread_priority(td, prio); 1332 } 1333 1334 /* 1335 * Restore a thread's priority when priority propagation is 1336 * over. The prio argument is the minimum priority the thread 1337 * needs to have to satisfy other possible priority lending 1338 * requests. If the thread's regular priority is less 1339 * important than prio, the thread will keep a priority boost 1340 * of prio. 1341 */ 1342 void 1343 sched_unlend_prio(struct thread *td, u_char prio) 1344 { 1345 u_char base_pri; 1346 1347 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 1348 td->td_base_pri <= PRI_MAX_TIMESHARE) 1349 base_pri = td->td_user_pri; 1350 else 1351 base_pri = td->td_base_pri; 1352 if (prio >= base_pri) { 1353 td->td_flags &= ~TDF_BORROWING; 1354 sched_thread_priority(td, base_pri); 1355 } else 1356 sched_lend_prio(td, prio); 1357 } 1358 1359 void 1360 sched_prio(struct thread *td, u_char prio) 1361 { 1362 u_char oldprio; 1363 1364 /* First, update the base priority. */ 1365 td->td_base_pri = prio; 1366 1367 /* 1368 * If the thread is borrowing another thread's priority, don't 1369 * ever lower the priority. 1370 */ 1371 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 1372 return; 1373 1374 /* Change the real priority. */ 1375 oldprio = td->td_priority; 1376 sched_thread_priority(td, prio); 1377 1378 /* 1379 * If the thread is on a turnstile, then let the turnstile update 1380 * its state. 1381 */ 1382 if (TD_ON_LOCK(td) && oldprio != prio) 1383 turnstile_adjust(td, oldprio); 1384 } 1385 1386 void 1387 sched_user_prio(struct thread *td, u_char prio) 1388 { 1389 u_char oldprio; 1390 1391 td->td_base_user_pri = prio; 1392 if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio) 1393 return; 1394 oldprio = td->td_user_pri; 1395 td->td_user_pri = prio; 1396 1397 if (TD_ON_UPILOCK(td) && oldprio != prio) 1398 umtx_pi_adjust(td, oldprio); 1399 } 1400 1401 void 1402 sched_lend_user_prio(struct thread *td, u_char prio) 1403 { 1404 u_char oldprio; 1405 1406 td->td_flags |= TDF_UBORROWING; 1407 1408 oldprio = td->td_user_pri; 1409 td->td_user_pri = prio; 1410 1411 if (TD_ON_UPILOCK(td) && oldprio != prio) 1412 umtx_pi_adjust(td, oldprio); 1413 } 1414 1415 void 1416 sched_unlend_user_prio(struct thread *td, u_char prio) 1417 { 1418 u_char base_pri; 1419 1420 base_pri = td->td_base_user_pri; 1421 if (prio >= base_pri) { 1422 td->td_flags &= ~TDF_UBORROWING; 1423 sched_user_prio(td, base_pri); 1424 } else 1425 sched_lend_user_prio(td, prio); 1426 } 1427 1428 void 1429 sched_switch(struct thread *td, struct thread *newtd, int flags) 1430 { 1431 struct tdq *tdq; 1432 struct td_sched *ts; 1433 int preempt; 1434 1435 THREAD_LOCK_ASSERT(td, MA_OWNED); 1436 1437 preempt = flags & SW_PREEMPT; 1438 tdq = TDQ_SELF(); 1439 ts = td->td_sched; 1440 td->td_lastcpu = td->td_oncpu; 1441 td->td_oncpu = NOCPU; 1442 td->td_flags &= ~TDF_NEEDRESCHED; 1443 td->td_owepreempt = 0; 1444 /* 1445 * If the thread has been assigned it may be in the process of switching 1446 * to the new cpu. This is the case in sched_bind(). 1447 */ 1448 /* 1449 * Switch to the sched lock to fix things up and pick 1450 * a new thread. 1451 */ 1452 if (td->td_lock != &sched_lock) { 1453 mtx_lock_spin(&sched_lock); 1454 thread_unlock(td); 1455 } 1456 if (TD_IS_IDLETHREAD(td)) { 1457 MPASS(td->td_lock == &sched_lock); 1458 TD_SET_CAN_RUN(td); 1459 } else if (TD_IS_RUNNING(td)) { 1460 /* 1461 * Don't allow the thread to migrate 1462 * from a preemption. 1463 */ 1464 tdq_load_rem(tdq, ts); 1465 if (preempt) 1466 sched_pin_td(td); 1467 sched_add(td, preempt ? 1468 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 1469 SRQ_OURSELF|SRQ_YIELDING); 1470 if (preempt) 1471 sched_unpin_td(td); 1472 } else 1473 tdq_load_rem(tdq, ts); 1474 mtx_assert(&sched_lock, MA_OWNED); 1475 if (newtd != NULL) { 1476 /* 1477 * If we bring in a thread account for it as if it had been 1478 * added to the run queue and then chosen. 1479 */ 1480 TD_SET_RUNNING(newtd); 1481 tdq_load_add(TDQ_SELF(), newtd->td_sched); 1482 } else 1483 newtd = choosethread(); 1484 if (td != newtd) { 1485 #ifdef HWPMC_HOOKS 1486 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1487 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1488 #endif 1489 1490 cpu_switch(td, newtd, td->td_lock); 1491 #ifdef HWPMC_HOOKS 1492 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1493 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1494 #endif 1495 } 1496 sched_lock.mtx_lock = (uintptr_t)td; 1497 td->td_oncpu = PCPU_GET(cpuid); 1498 MPASS(td->td_lock == &sched_lock); 1499 } 1500 1501 void 1502 sched_nice(struct proc *p, int nice) 1503 { 1504 struct thread *td; 1505 1506 PROC_LOCK_ASSERT(p, MA_OWNED); 1507 PROC_SLOCK_ASSERT(p, MA_OWNED); 1508 1509 p->p_nice = nice; 1510 FOREACH_THREAD_IN_PROC(p, td) { 1511 thread_lock(td); 1512 sched_priority(td); 1513 sched_prio(td, td->td_base_user_pri); 1514 thread_unlock(td); 1515 } 1516 } 1517 1518 void 1519 sched_sleep(struct thread *td) 1520 { 1521 1522 THREAD_LOCK_ASSERT(td, MA_OWNED); 1523 1524 td->td_sched->ts_slptime = ticks; 1525 } 1526 1527 void 1528 sched_wakeup(struct thread *td) 1529 { 1530 struct td_sched *ts; 1531 int slptime; 1532 1533 THREAD_LOCK_ASSERT(td, MA_OWNED); 1534 ts = td->td_sched; 1535 /* 1536 * If we slept for more than a tick update our interactivity and 1537 * priority. 1538 */ 1539 slptime = ts->ts_slptime; 1540 ts->ts_slptime = 0; 1541 if (slptime && slptime != ticks) { 1542 u_int hzticks; 1543 1544 hzticks = (ticks - slptime) << SCHED_TICK_SHIFT; 1545 ts->skg_slptime += hzticks; 1546 sched_interact_update(td); 1547 sched_pctcpu_update(ts); 1548 sched_priority(td); 1549 } 1550 /* Reset the slice value after we sleep. */ 1551 ts->ts_slice = sched_slice; 1552 sched_add(td, SRQ_BORING); 1553 } 1554 1555 /* 1556 * Penalize the parent for creating a new child and initialize the child's 1557 * priority. 1558 */ 1559 void 1560 sched_fork(struct thread *td, struct thread *child) 1561 { 1562 THREAD_LOCK_ASSERT(td, MA_OWNED); 1563 sched_fork_thread(td, child); 1564 /* 1565 * Penalize the parent and child for forking. 1566 */ 1567 sched_interact_fork(child); 1568 sched_priority(child); 1569 td->td_sched->skg_runtime += tickincr; 1570 sched_interact_update(td); 1571 sched_priority(td); 1572 } 1573 1574 void 1575 sched_fork_thread(struct thread *td, struct thread *child) 1576 { 1577 struct td_sched *ts; 1578 struct td_sched *ts2; 1579 1580 /* 1581 * Initialize child. 1582 */ 1583 THREAD_LOCK_ASSERT(td, MA_OWNED); 1584 sched_newthread(child); 1585 child->td_lock = &sched_lock; 1586 ts = td->td_sched; 1587 ts2 = child->td_sched; 1588 ts2->ts_cpu = ts->ts_cpu; 1589 ts2->ts_runq = NULL; 1590 /* 1591 * Grab our parents cpu estimation information and priority. 1592 */ 1593 ts2->ts_ticks = ts->ts_ticks; 1594 ts2->ts_ltick = ts->ts_ltick; 1595 ts2->ts_ftick = ts->ts_ftick; 1596 child->td_user_pri = td->td_user_pri; 1597 child->td_base_user_pri = td->td_base_user_pri; 1598 /* 1599 * And update interactivity score. 1600 */ 1601 ts2->skg_slptime = ts->skg_slptime; 1602 ts2->skg_runtime = ts->skg_runtime; 1603 ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */ 1604 } 1605 1606 void 1607 sched_class(struct thread *td, int class) 1608 { 1609 1610 THREAD_LOCK_ASSERT(td, MA_OWNED); 1611 if (td->td_pri_class == class) 1612 return; 1613 1614 #ifdef SMP 1615 /* 1616 * On SMP if we're on the RUNQ we must adjust the transferable 1617 * count because could be changing to or from an interrupt 1618 * class. 1619 */ 1620 if (TD_ON_RUNQ(td)) { 1621 struct tdq *tdq; 1622 1623 tdq = TDQ_CPU(td->td_sched->ts_cpu); 1624 if (THREAD_CAN_MIGRATE(td)) { 1625 tdq->tdq_transferable--; 1626 tdq->tdq_group->tdg_transferable--; 1627 } 1628 td->td_pri_class = class; 1629 if (THREAD_CAN_MIGRATE(td)) { 1630 tdq->tdq_transferable++; 1631 tdq->tdq_group->tdg_transferable++; 1632 } 1633 } 1634 #endif 1635 td->td_pri_class = class; 1636 } 1637 1638 /* 1639 * Return some of the child's priority and interactivity to the parent. 1640 */ 1641 void 1642 sched_exit(struct proc *p, struct thread *child) 1643 { 1644 struct thread *td; 1645 1646 CTR3(KTR_SCHED, "sched_exit: %p(%s) prio %d", 1647 child, child->td_proc->p_comm, child->td_priority); 1648 1649 PROC_SLOCK_ASSERT(p, MA_OWNED); 1650 td = FIRST_THREAD_IN_PROC(p); 1651 sched_exit_thread(td, child); 1652 } 1653 1654 void 1655 sched_exit_thread(struct thread *td, struct thread *child) 1656 { 1657 1658 CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d", 1659 child, child->td_proc->p_comm, child->td_priority); 1660 1661 thread_lock(child); 1662 tdq_load_rem(TDQ_CPU(child->td_sched->ts_cpu), child->td_sched); 1663 thread_unlock(child); 1664 #ifdef KSE 1665 /* 1666 * KSE forks and exits so often that this penalty causes short-lived 1667 * threads to always be non-interactive. This causes mozilla to 1668 * crawl under load. 1669 */ 1670 if ((td->td_pflags & TDP_SA) && td->td_proc == child->td_proc) 1671 return; 1672 #endif 1673 /* 1674 * Give the child's runtime to the parent without returning the 1675 * sleep time as a penalty to the parent. This causes shells that 1676 * launch expensive things to mark their children as expensive. 1677 */ 1678 thread_lock(td); 1679 td->td_sched->skg_runtime += child->td_sched->skg_runtime; 1680 sched_interact_update(td); 1681 sched_priority(td); 1682 thread_unlock(td); 1683 } 1684 1685 void 1686 sched_userret(struct thread *td) 1687 { 1688 /* 1689 * XXX we cheat slightly on the locking here to avoid locking in 1690 * the usual case. Setting td_priority here is essentially an 1691 * incomplete workaround for not setting it properly elsewhere. 1692 * Now that some interrupt handlers are threads, not setting it 1693 * properly elsewhere can clobber it in the window between setting 1694 * it here and returning to user mode, so don't waste time setting 1695 * it perfectly here. 1696 */ 1697 KASSERT((td->td_flags & TDF_BORROWING) == 0, 1698 ("thread with borrowed priority returning to userland")); 1699 if (td->td_priority != td->td_user_pri) { 1700 thread_lock(td); 1701 td->td_priority = td->td_user_pri; 1702 td->td_base_pri = td->td_user_pri; 1703 thread_unlock(td); 1704 } 1705 } 1706 1707 void 1708 sched_clock(struct thread *td) 1709 { 1710 struct tdq *tdq; 1711 struct td_sched *ts; 1712 1713 mtx_assert(&sched_lock, MA_OWNED); 1714 #ifdef SMP 1715 sched_smp_tick(td); 1716 #endif 1717 tdq = TDQ_SELF(); 1718 /* 1719 * Advance the insert index once for each tick to ensure that all 1720 * threads get a chance to run. 1721 */ 1722 if (tdq->tdq_idx == tdq->tdq_ridx) { 1723 tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS; 1724 if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx])) 1725 tdq->tdq_ridx = tdq->tdq_idx; 1726 } 1727 ts = td->td_sched; 1728 /* 1729 * We only do slicing code for TIMESHARE threads. 1730 */ 1731 if (td->td_pri_class != PRI_TIMESHARE) 1732 return; 1733 /* 1734 * We used a tick; charge it to the thread so that we can compute our 1735 * interactivity. 1736 */ 1737 td->td_sched->skg_runtime += tickincr; 1738 sched_interact_update(td); 1739 /* 1740 * We used up one time slice. 1741 */ 1742 if (--ts->ts_slice > 0) 1743 return; 1744 /* 1745 * We're out of time, recompute priorities and requeue. 1746 */ 1747 sched_priority(td); 1748 td->td_flags |= TDF_NEEDRESCHED; 1749 } 1750 1751 int 1752 sched_runnable(void) 1753 { 1754 struct tdq *tdq; 1755 int load; 1756 1757 load = 1; 1758 1759 tdq = TDQ_SELF(); 1760 #ifdef SMP 1761 if (tdq_busy) 1762 goto out; 1763 #endif 1764 if ((curthread->td_flags & TDF_IDLETD) != 0) { 1765 if (tdq->tdq_load > 0) 1766 goto out; 1767 } else 1768 if (tdq->tdq_load - 1 > 0) 1769 goto out; 1770 load = 0; 1771 out: 1772 return (load); 1773 } 1774 1775 struct thread * 1776 sched_choose(void) 1777 { 1778 struct tdq *tdq; 1779 struct td_sched *ts; 1780 1781 mtx_assert(&sched_lock, MA_OWNED); 1782 tdq = TDQ_SELF(); 1783 #ifdef SMP 1784 restart: 1785 #endif 1786 ts = tdq_choose(tdq); 1787 if (ts) { 1788 #ifdef SMP 1789 if (ts->ts_thread->td_priority > PRI_MIN_IDLE) 1790 if (tdq_idled(tdq) == 0) 1791 goto restart; 1792 #endif 1793 tdq_runq_rem(tdq, ts); 1794 return (ts->ts_thread); 1795 } 1796 #ifdef SMP 1797 if (tdq_idled(tdq) == 0) 1798 goto restart; 1799 #endif 1800 return (PCPU_GET(idlethread)); 1801 } 1802 1803 static int 1804 sched_preempt(struct thread *td) 1805 { 1806 struct thread *ctd; 1807 int cpri; 1808 int pri; 1809 1810 ctd = curthread; 1811 pri = td->td_priority; 1812 cpri = ctd->td_priority; 1813 if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) 1814 return (0); 1815 /* 1816 * Always preempt IDLE threads. Otherwise only if the preempting 1817 * thread is an ithread. 1818 */ 1819 if (pri > PRI_MAX_ITHD && cpri < PRI_MIN_IDLE) 1820 return (0); 1821 if (ctd->td_critnest > 1) { 1822 CTR1(KTR_PROC, "sched_preempt: in critical section %d", 1823 ctd->td_critnest); 1824 ctd->td_owepreempt = 1; 1825 return (0); 1826 } 1827 /* 1828 * Thread is runnable but not yet put on system run queue. 1829 */ 1830 MPASS(TD_ON_RUNQ(td)); 1831 TD_SET_RUNNING(td); 1832 MPASS(ctd->td_lock == &sched_lock); 1833 MPASS(td->td_lock == &sched_lock); 1834 CTR3(KTR_PROC, "preempting to thread %p (pid %d, %s)\n", td, 1835 td->td_proc->p_pid, td->td_proc->p_comm); 1836 /* 1837 * We enter the switch with two runnable threads that both have 1838 * the same lock. When we return td may be sleeping so we need 1839 * to switch locks to make sure he's locked correctly. 1840 */ 1841 SCHED_STAT_INC(switch_preempt); 1842 mi_switch(SW_INVOL|SW_PREEMPT, td); 1843 spinlock_enter(); 1844 thread_unlock(ctd); 1845 thread_lock(td); 1846 spinlock_exit(); 1847 1848 return (1); 1849 } 1850 1851 void 1852 sched_add(struct thread *td, int flags) 1853 { 1854 struct tdq *tdq; 1855 struct td_sched *ts; 1856 int preemptive; 1857 int class; 1858 #ifdef SMP 1859 int cpuid; 1860 int cpumask; 1861 #endif 1862 ts = td->td_sched; 1863 1864 THREAD_LOCK_ASSERT(td, MA_OWNED); 1865 CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)", 1866 td, td->td_proc->p_comm, td->td_priority, curthread, 1867 curthread->td_proc->p_comm); 1868 KASSERT((td->td_inhibitors == 0), 1869 ("sched_add: trying to run inhibited thread")); 1870 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 1871 ("sched_add: bad thread state")); 1872 KASSERT(td->td_proc->p_sflag & PS_INMEM, 1873 ("sched_add: process swapped out")); 1874 /* 1875 * Now that the thread is moving to the run-queue, set the lock 1876 * to the scheduler's lock. 1877 */ 1878 if (td->td_lock != &sched_lock) { 1879 mtx_lock_spin(&sched_lock); 1880 thread_lock_set(td, &sched_lock); 1881 } 1882 mtx_assert(&sched_lock, MA_OWNED); 1883 TD_SET_RUNQ(td); 1884 tdq = TDQ_SELF(); 1885 class = PRI_BASE(td->td_pri_class); 1886 preemptive = !(flags & SRQ_YIELDING); 1887 /* 1888 * Recalculate the priority before we select the target cpu or 1889 * run-queue. 1890 */ 1891 if (class == PRI_TIMESHARE) 1892 sched_priority(td); 1893 if (ts->ts_slice == 0) 1894 ts->ts_slice = sched_slice; 1895 #ifdef SMP 1896 cpuid = PCPU_GET(cpuid); 1897 /* 1898 * Pick the destination cpu and if it isn't ours transfer to the 1899 * target cpu. 1900 */ 1901 if (THREAD_CAN_MIGRATE(td)) { 1902 if (td->td_priority <= PRI_MAX_ITHD) { 1903 CTR2(KTR_ULE, "ithd %d < %d", 1904 td->td_priority, PRI_MAX_ITHD); 1905 ts->ts_cpu = cpuid; 1906 } else if (pick_pri) 1907 ts->ts_cpu = tdq_pickpri(tdq, ts, flags); 1908 else 1909 ts->ts_cpu = tdq_pickidle(tdq, ts); 1910 } else 1911 CTR1(KTR_ULE, "pinned %d", td->td_pinned); 1912 if (ts->ts_cpu != cpuid) 1913 preemptive = 0; 1914 tdq = TDQ_CPU(ts->ts_cpu); 1915 cpumask = 1 << ts->ts_cpu; 1916 /* 1917 * If we had been idle, clear our bit in the group and potentially 1918 * the global bitmap. 1919 */ 1920 if ((class != PRI_IDLE && class != PRI_ITHD) && 1921 (tdq->tdq_group->tdg_idlemask & cpumask) != 0) { 1922 /* 1923 * Check to see if our group is unidling, and if so, remove it 1924 * from the global idle mask. 1925 */ 1926 if (tdq->tdq_group->tdg_idlemask == 1927 tdq->tdq_group->tdg_cpumask) 1928 atomic_clear_int(&tdq_idle, tdq->tdq_group->tdg_mask); 1929 /* 1930 * Now remove ourselves from the group specific idle mask. 1931 */ 1932 tdq->tdq_group->tdg_idlemask &= ~cpumask; 1933 } 1934 #endif 1935 /* 1936 * Pick the run queue based on priority. 1937 */ 1938 if (td->td_priority <= PRI_MAX_REALTIME) 1939 ts->ts_runq = &tdq->tdq_realtime; 1940 else if (td->td_priority <= PRI_MAX_TIMESHARE) 1941 ts->ts_runq = &tdq->tdq_timeshare; 1942 else 1943 ts->ts_runq = &tdq->tdq_idle; 1944 if (preemptive && sched_preempt(td)) 1945 return; 1946 tdq_runq_add(tdq, ts, flags); 1947 tdq_load_add(tdq, ts); 1948 #ifdef SMP 1949 if (ts->ts_cpu != cpuid) { 1950 tdq_notify(ts); 1951 return; 1952 } 1953 #endif 1954 if (td->td_priority < curthread->td_priority) 1955 curthread->td_flags |= TDF_NEEDRESCHED; 1956 } 1957 1958 void 1959 sched_rem(struct thread *td) 1960 { 1961 struct tdq *tdq; 1962 struct td_sched *ts; 1963 1964 CTR5(KTR_SCHED, "sched_rem: %p(%s) prio %d by %p(%s)", 1965 td, td->td_proc->p_comm, td->td_priority, curthread, 1966 curthread->td_proc->p_comm); 1967 THREAD_LOCK_ASSERT(td, MA_OWNED); 1968 ts = td->td_sched; 1969 KASSERT(TD_ON_RUNQ(td), 1970 ("sched_rem: thread not on run queue")); 1971 1972 tdq = TDQ_CPU(ts->ts_cpu); 1973 tdq_runq_rem(tdq, ts); 1974 tdq_load_rem(tdq, ts); 1975 TD_SET_CAN_RUN(td); 1976 } 1977 1978 fixpt_t 1979 sched_pctcpu(struct thread *td) 1980 { 1981 fixpt_t pctcpu; 1982 struct td_sched *ts; 1983 1984 pctcpu = 0; 1985 ts = td->td_sched; 1986 if (ts == NULL) 1987 return (0); 1988 1989 thread_lock(td); 1990 if (ts->ts_ticks) { 1991 int rtick; 1992 1993 sched_pctcpu_update(ts); 1994 /* How many rtick per second ? */ 1995 rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz); 1996 pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT; 1997 } 1998 td->td_proc->p_swtime = ts->ts_ltick - ts->ts_ftick; 1999 thread_unlock(td); 2000 2001 return (pctcpu); 2002 } 2003 2004 void 2005 sched_bind(struct thread *td, int cpu) 2006 { 2007 struct td_sched *ts; 2008 2009 THREAD_LOCK_ASSERT(td, MA_OWNED); 2010 ts = td->td_sched; 2011 if (ts->ts_flags & TSF_BOUND) 2012 sched_unbind(td); 2013 ts->ts_flags |= TSF_BOUND; 2014 #ifdef SMP 2015 sched_pin(); 2016 if (PCPU_GET(cpuid) == cpu) 2017 return; 2018 ts->ts_cpu = cpu; 2019 /* When we return from mi_switch we'll be on the correct cpu. */ 2020 mi_switch(SW_VOL, NULL); 2021 #endif 2022 } 2023 2024 void 2025 sched_unbind(struct thread *td) 2026 { 2027 struct td_sched *ts; 2028 2029 THREAD_LOCK_ASSERT(td, MA_OWNED); 2030 ts = td->td_sched; 2031 if ((ts->ts_flags & TSF_BOUND) == 0) 2032 return; 2033 ts->ts_flags &= ~TSF_BOUND; 2034 #ifdef SMP 2035 sched_unpin(); 2036 #endif 2037 } 2038 2039 int 2040 sched_is_bound(struct thread *td) 2041 { 2042 THREAD_LOCK_ASSERT(td, MA_OWNED); 2043 return (td->td_sched->ts_flags & TSF_BOUND); 2044 } 2045 2046 void 2047 sched_relinquish(struct thread *td) 2048 { 2049 thread_lock(td); 2050 if (td->td_pri_class == PRI_TIMESHARE) 2051 sched_prio(td, PRI_MAX_TIMESHARE); 2052 SCHED_STAT_INC(switch_relinquish); 2053 mi_switch(SW_VOL, NULL); 2054 thread_unlock(td); 2055 } 2056 2057 int 2058 sched_load(void) 2059 { 2060 #ifdef SMP 2061 int total; 2062 int i; 2063 2064 total = 0; 2065 for (i = 0; i <= tdg_maxid; i++) 2066 total += TDQ_GROUP(i)->tdg_load; 2067 return (total); 2068 #else 2069 return (TDQ_SELF()->tdq_sysload); 2070 #endif 2071 } 2072 2073 int 2074 sched_sizeof_proc(void) 2075 { 2076 return (sizeof(struct proc)); 2077 } 2078 2079 int 2080 sched_sizeof_thread(void) 2081 { 2082 return (sizeof(struct thread) + sizeof(struct td_sched)); 2083 } 2084 2085 void 2086 sched_tick(void) 2087 { 2088 struct td_sched *ts; 2089 2090 ts = curthread->td_sched; 2091 /* Adjust ticks for pctcpu */ 2092 ts->ts_ticks += 1 << SCHED_TICK_SHIFT; 2093 ts->ts_ltick = ticks; 2094 /* 2095 * Update if we've exceeded our desired tick threshhold by over one 2096 * second. 2097 */ 2098 if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick) 2099 sched_pctcpu_update(ts); 2100 } 2101 2102 /* 2103 * The actual idle process. 2104 */ 2105 void 2106 sched_idletd(void *dummy) 2107 { 2108 struct proc *p; 2109 struct thread *td; 2110 2111 td = curthread; 2112 p = td->td_proc; 2113 mtx_assert(&Giant, MA_NOTOWNED); 2114 /* ULE Relies on preemption for idle interruption. */ 2115 for (;;) 2116 cpu_idle(); 2117 } 2118 2119 /* 2120 * A CPU is entering for the first time or a thread is exiting. 2121 */ 2122 void 2123 sched_throw(struct thread *td) 2124 { 2125 /* 2126 * Correct spinlock nesting. The idle thread context that we are 2127 * borrowing was created so that it would start out with a single 2128 * spin lock (sched_lock) held in fork_trampoline(). Since we've 2129 * explicitly acquired locks in this function, the nesting count 2130 * is now 2 rather than 1. Since we are nested, calling 2131 * spinlock_exit() will simply adjust the counts without allowing 2132 * spin lock using code to interrupt us. 2133 */ 2134 if (td == NULL) { 2135 mtx_lock_spin(&sched_lock); 2136 spinlock_exit(); 2137 } else { 2138 MPASS(td->td_lock == &sched_lock); 2139 } 2140 mtx_assert(&sched_lock, MA_OWNED); 2141 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 2142 PCPU_SET(switchtime, cpu_ticks()); 2143 PCPU_SET(switchticks, ticks); 2144 cpu_throw(td, choosethread()); /* doesn't return */ 2145 } 2146 2147 void 2148 sched_fork_exit(struct thread *ctd) 2149 { 2150 struct thread *td; 2151 2152 /* 2153 * Finish setting up thread glue so that it begins execution in a 2154 * non-nested critical section with sched_lock held but not recursed. 2155 */ 2156 ctd->td_oncpu = PCPU_GET(cpuid); 2157 sched_lock.mtx_lock = (uintptr_t)ctd; 2158 THREAD_LOCK_ASSERT(ctd, MA_OWNED | MA_NOTRECURSED); 2159 /* 2160 * Processes normally resume in mi_switch() after being 2161 * cpu_switch()'ed to, but when children start up they arrive here 2162 * instead, so we must do much the same things as mi_switch() would. 2163 */ 2164 if ((td = PCPU_GET(deadthread))) { 2165 PCPU_SET(deadthread, NULL); 2166 thread_stash(td); 2167 } 2168 thread_unlock(ctd); 2169 } 2170 2171 static SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); 2172 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ule", 0, 2173 "Scheduler name"); 2174 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, ""); 2175 SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0, ""); 2176 SYSCTL_INT(_kern_sched, OID_AUTO, tickincr, CTLFLAG_RD, &tickincr, 0, ""); 2177 SYSCTL_INT(_kern_sched, OID_AUTO, realstathz, CTLFLAG_RD, &realstathz, 0, ""); 2178 #ifdef SMP 2179 SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri, CTLFLAG_RW, &pick_pri, 0, ""); 2180 SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri_affinity, CTLFLAG_RW, 2181 &affinity, 0, ""); 2182 SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri_tryself, CTLFLAG_RW, 2183 &tryself, 0, ""); 2184 SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri_tryselfidle, CTLFLAG_RW, 2185 &tryselfidle, 0, ""); 2186 SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0, ""); 2187 SYSCTL_INT(_kern_sched, OID_AUTO, ipi_preempt, CTLFLAG_RW, &ipi_preempt, 0, ""); 2188 SYSCTL_INT(_kern_sched, OID_AUTO, ipi_ast, CTLFLAG_RW, &ipi_ast, 0, ""); 2189 SYSCTL_INT(_kern_sched, OID_AUTO, ipi_thresh, CTLFLAG_RW, &ipi_thresh, 0, ""); 2190 SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0, ""); 2191 SYSCTL_INT(_kern_sched, OID_AUTO, steal_busy, CTLFLAG_RW, &steal_busy, 0, ""); 2192 SYSCTL_INT(_kern_sched, OID_AUTO, busy_thresh, CTLFLAG_RW, &busy_thresh, 0, ""); 2193 SYSCTL_INT(_kern_sched, OID_AUTO, topology, CTLFLAG_RD, &topology, 0, ""); 2194 #endif 2195 2196 /* ps compat */ 2197 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 2198 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 2199 2200 2201 #define KERN_SWITCH_INCLUDE 1 2202 #include "kern/kern_switch.c" 2203