1/*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1990, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37#include <sys/cdefs.h> 38#include "opt_hwpmc_hooks.h" 39#include "opt_sched.h" 40 41#include <sys/param.h> 42#include <sys/systm.h> 43#include <sys/cpuset.h> 44#include <sys/kernel.h> 45#include <sys/ktr.h> 46#include <sys/lock.h> 47#include <sys/kthread.h> 48#include <sys/mutex.h> 49#include <sys/proc.h> 50#include <sys/resourcevar.h> 51#include <sys/sched.h> 52#include <sys/sdt.h> 53#include <sys/smp.h> 54#include <sys/sysctl.h> 55#include <sys/sx.h> 56#include <sys/turnstile.h> 57#include <sys/umtxvar.h> 58#include <machine/pcb.h> 59#include <machine/smp.h> 60 61#ifdef HWPMC_HOOKS 62#include <sys/pmckern.h> 63#endif 64 65#ifdef KDTRACE_HOOKS 66#include <sys/dtrace_bsd.h> 67int __read_mostly dtrace_vtime_active; 68dtrace_vtime_switch_func_t dtrace_vtime_switch_func; 69#endif 70 71/* 72 * INVERSE_ESTCPU_WEIGHT is only suitable for statclock() frequencies in 73 * the range 100-256 Hz (approximately). 74 */ 75#define ESTCPULIM(e) \ 76 min((e), INVERSE_ESTCPU_WEIGHT * (NICE_WEIGHT * (PRIO_MAX - PRIO_MIN) - \ 77 RQ_PPQ) + INVERSE_ESTCPU_WEIGHT - 1) 78#ifdef SMP 79#define INVERSE_ESTCPU_WEIGHT (8 * smp_cpus) 80#else 81#define INVERSE_ESTCPU_WEIGHT 8 /* 1 / (priorities per estcpu level). */ 82#endif 83#define NICE_WEIGHT 1 /* Priorities per nice level. */ 84 85#define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX))) 86 87/* 88 * The schedulable entity that runs a context. 89 * This is an extension to the thread structure and is tailored to 90 * the requirements of this scheduler. 91 * All fields are protected by the scheduler lock. 92 */ 93struct td_sched { 94 fixpt_t ts_pctcpu; /* %cpu during p_swtime. */ 95 u_int ts_estcpu; /* Estimated cpu utilization. */ 96 int ts_cpticks; /* Ticks of cpu time. */ 97 int ts_slptime; /* Seconds !RUNNING. */ 98 int ts_slice; /* Remaining part of time slice. */ 99 int ts_flags; 100 struct runq *ts_runq; /* runq the thread is currently on */ 101#ifdef KTR 102 char ts_name[TS_NAME_LEN]; 103#endif 104}; 105 106/* flags kept in td_flags */ 107#define TDF_DIDRUN TDF_SCHED0 /* thread actually ran. */ 108#define TDF_BOUND TDF_SCHED1 /* Bound to one CPU. */ 109#define TDF_SLICEEND TDF_SCHED2 /* Thread time slice is over. */ 110 111/* flags kept in ts_flags */ 112#define TSF_AFFINITY 0x0001 /* Has a non-"full" CPU set. */ 113 114#define SKE_RUNQ_PCPU(ts) \ 115 ((ts)->ts_runq != 0 && (ts)->ts_runq != &runq) 116 117#define THREAD_CAN_SCHED(td, cpu) \ 118 CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask) 119 120_Static_assert(sizeof(struct thread) + sizeof(struct td_sched) <= 121 sizeof(struct thread0_storage), 122 "increase struct thread0_storage.t0st_sched size"); 123 124static struct mtx sched_lock; 125 126static int realstathz = 127; /* stathz is sometimes 0 and run off of hz. */ 127static int sched_tdcnt; /* Total runnable threads in the system. */ 128static int sched_slice = 12; /* Thread run time before rescheduling. */ 129 130static void setup_runqs(void); 131static void schedcpu(void); 132static void schedcpu_thread(void); 133static void sched_priority(struct thread *td, u_char prio); 134static void sched_setup(void *dummy); 135static void maybe_resched(struct thread *td); 136static void updatepri(struct thread *td); 137static void resetpriority(struct thread *td); 138static void resetpriority_thread(struct thread *td); 139#ifdef SMP 140static int sched_pickcpu(struct thread *td); 141static int forward_wakeup(int cpunum); 142static void kick_other_cpu(int pri, int cpuid); 143#endif 144 145static struct kproc_desc sched_kp = { 146 "schedcpu", 147 schedcpu_thread, 148 NULL 149}; 150SYSINIT(schedcpu, SI_SUB_LAST, SI_ORDER_FIRST, kproc_start, 151 &sched_kp); 152SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL); 153 154static void sched_initticks(void *dummy); 155SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, 156 NULL); 157 158/* 159 * Global run queue. 160 */ 161static struct runq runq; 162 163#ifdef SMP 164/* 165 * Per-CPU run queues 166 */ 167static struct runq runq_pcpu[MAXCPU]; 168long runq_length[MAXCPU]; 169 170static cpuset_t idle_cpus_mask; 171#endif 172 173struct pcpuidlestat { 174 u_int idlecalls; 175 u_int oldidlecalls; 176}; 177DPCPU_DEFINE_STATIC(struct pcpuidlestat, idlestat); 178 179static void 180setup_runqs(void) 181{ 182#ifdef SMP 183 int i; 184 185 for (i = 0; i < MAXCPU; ++i) 186 runq_init(&runq_pcpu[i]); 187#endif 188 189 runq_init(&runq); 190} 191 192static int 193sysctl_kern_quantum(SYSCTL_HANDLER_ARGS) 194{ 195 int error, new_val, period; 196 197 period = 1000000 / realstathz; 198 new_val = period * sched_slice; 199 error = sysctl_handle_int(oidp, &new_val, 0, req); 200 if (error != 0 || req->newptr == NULL) 201 return (error); 202 if (new_val <= 0) 203 return (EINVAL); 204 sched_slice = imax(1, (new_val + period / 2) / period); 205 hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) / 206 realstathz); 207 return (0); 208} 209 210SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 211 "Scheduler"); 212 213SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "4BSD", 0, 214 "Scheduler name"); 215SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, 216 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0, 217 sysctl_kern_quantum, "I", 218 "Quantum for timeshare threads in microseconds"); 219SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, 220 "Quantum for timeshare threads in stathz ticks"); 221#ifdef SMP 222/* Enable forwarding of wakeups to all other cpus */ 223static SYSCTL_NODE(_kern_sched, OID_AUTO, ipiwakeup, 224 CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 225 "Kernel SMP"); 226 227static int runq_fuzz = 1; 228SYSCTL_INT(_kern_sched, OID_AUTO, runq_fuzz, CTLFLAG_RW, &runq_fuzz, 0, ""); 229 230static int forward_wakeup_enabled = 1; 231SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, enabled, CTLFLAG_RW, 232 &forward_wakeup_enabled, 0, 233 "Forwarding of wakeup to idle CPUs"); 234 235static int forward_wakeups_requested = 0; 236SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, requested, CTLFLAG_RD, 237 &forward_wakeups_requested, 0, 238 "Requests for Forwarding of wakeup to idle CPUs"); 239 240static int forward_wakeups_delivered = 0; 241SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, delivered, CTLFLAG_RD, 242 &forward_wakeups_delivered, 0, 243 "Completed Forwarding of wakeup to idle CPUs"); 244 245static int forward_wakeup_use_mask = 1; 246SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, usemask, CTLFLAG_RW, 247 &forward_wakeup_use_mask, 0, 248 "Use the mask of idle cpus"); 249 250static int forward_wakeup_use_loop = 0; 251SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, useloop, CTLFLAG_RW, 252 &forward_wakeup_use_loop, 0, 253 "Use a loop to find idle cpus"); 254 255#endif 256#if 0 257static int sched_followon = 0; 258SYSCTL_INT(_kern_sched, OID_AUTO, followon, CTLFLAG_RW, 259 &sched_followon, 0, 260 "allow threads to share a quantum"); 261#endif 262 263SDT_PROVIDER_DEFINE(sched); 264 265SDT_PROBE_DEFINE3(sched, , , change__pri, "struct thread *", 266 "struct proc *", "uint8_t"); 267SDT_PROBE_DEFINE3(sched, , , dequeue, "struct thread *", 268 "struct proc *", "void *"); 269SDT_PROBE_DEFINE4(sched, , , enqueue, "struct thread *", 270 "struct proc *", "void *", "int"); 271SDT_PROBE_DEFINE4(sched, , , lend__pri, "struct thread *", 272 "struct proc *", "uint8_t", "struct thread *"); 273SDT_PROBE_DEFINE2(sched, , , load__change, "int", "int"); 274SDT_PROBE_DEFINE2(sched, , , off__cpu, "struct thread *", 275 "struct proc *"); 276SDT_PROBE_DEFINE(sched, , , on__cpu); 277SDT_PROBE_DEFINE(sched, , , remain__cpu); 278SDT_PROBE_DEFINE2(sched, , , surrender, "struct thread *", 279 "struct proc *"); 280 281static __inline void 282sched_load_add(void) 283{ 284 285 sched_tdcnt++; 286 KTR_COUNTER0(KTR_SCHED, "load", "global load", sched_tdcnt); 287 SDT_PROBE2(sched, , , load__change, NOCPU, sched_tdcnt); 288} 289 290static __inline void 291sched_load_rem(void) 292{ 293 294 sched_tdcnt--; 295 KTR_COUNTER0(KTR_SCHED, "load", "global load", sched_tdcnt); 296 SDT_PROBE2(sched, , , load__change, NOCPU, sched_tdcnt); 297} 298/* 299 * Arrange to reschedule if necessary, taking the priorities and 300 * schedulers into account. 301 */ 302static void 303maybe_resched(struct thread *td) 304{ 305 306 THREAD_LOCK_ASSERT(td, MA_OWNED); 307 if (td->td_priority < curthread->td_priority) 308 ast_sched_locked(curthread, TDA_SCHED); 309} 310 311/* 312 * This function is called when a thread is about to be put on run queue 313 * because it has been made runnable or its priority has been adjusted. It 314 * determines if the new thread should preempt the current thread. If so, 315 * it sets td_owepreempt to request a preemption. 316 */ 317int 318maybe_preempt(struct thread *td) 319{ 320#ifdef PREEMPTION 321 struct thread *ctd; 322 int cpri, pri; 323 324 /* 325 * The new thread should not preempt the current thread if any of the 326 * following conditions are true: 327 * 328 * - The kernel is in the throes of crashing (panicstr). 329 * - The current thread has a higher (numerically lower) or 330 * equivalent priority. Note that this prevents curthread from 331 * trying to preempt to itself. 332 * - The current thread has an inhibitor set or is in the process of 333 * exiting. In this case, the current thread is about to switch 334 * out anyways, so there's no point in preempting. If we did, 335 * the current thread would not be properly resumed as well, so 336 * just avoid that whole landmine. 337 * - If the new thread's priority is not a realtime priority and 338 * the current thread's priority is not an idle priority and 339 * FULL_PREEMPTION is disabled. 340 * 341 * If all of these conditions are false, but the current thread is in 342 * a nested critical section, then we have to defer the preemption 343 * until we exit the critical section. Otherwise, switch immediately 344 * to the new thread. 345 */ 346 ctd = curthread; 347 THREAD_LOCK_ASSERT(td, MA_OWNED); 348 KASSERT((td->td_inhibitors == 0), 349 ("maybe_preempt: trying to run inhibited thread")); 350 pri = td->td_priority; 351 cpri = ctd->td_priority; 352 if (KERNEL_PANICKED() || pri >= cpri /* || dumping */ || 353 TD_IS_INHIBITED(ctd)) 354 return (0); 355#ifndef FULL_PREEMPTION 356 if (pri > PRI_MAX_ITHD && cpri < PRI_MIN_IDLE) 357 return (0); 358#endif 359 360 CTR0(KTR_PROC, "maybe_preempt: scheduling preemption"); 361 ctd->td_owepreempt = 1; 362 return (1); 363#else 364 return (0); 365#endif 366} 367 368/* 369 * Constants for digital decay and forget: 370 * 90% of (ts_estcpu) usage in 5 * loadav time 371 * 95% of (ts_pctcpu) usage in 60 seconds (load insensitive) 372 * Note that, as ps(1) mentions, this can let percentages 373 * total over 100% (I've seen 137.9% for 3 processes). 374 * 375 * Note that schedclock() updates ts_estcpu and p_cpticks asynchronously. 376 * 377 * We wish to decay away 90% of ts_estcpu in (5 * loadavg) seconds. 378 * That is, the system wants to compute a value of decay such 379 * that the following for loop: 380 * for (i = 0; i < (5 * loadavg); i++) 381 * ts_estcpu *= decay; 382 * will compute 383 * ts_estcpu *= 0.1; 384 * for all values of loadavg: 385 * 386 * Mathematically this loop can be expressed by saying: 387 * decay ** (5 * loadavg) ~= .1 388 * 389 * The system computes decay as: 390 * decay = (2 * loadavg) / (2 * loadavg + 1) 391 * 392 * We wish to prove that the system's computation of decay 393 * will always fulfill the equation: 394 * decay ** (5 * loadavg) ~= .1 395 * 396 * If we compute b as: 397 * b = 2 * loadavg 398 * then 399 * decay = b / (b + 1) 400 * 401 * We now need to prove two things: 402 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1) 403 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg) 404 * 405 * Facts: 406 * For x close to zero, exp(x) =~ 1 + x, since 407 * exp(x) = 0! + x**1/1! + x**2/2! + ... . 408 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b. 409 * For x close to zero, ln(1+x) =~ x, since 410 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1 411 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1). 412 * ln(.1) =~ -2.30 413 * 414 * Proof of (1): 415 * Solve (factor)**(power) =~ .1 given power (5*loadav): 416 * solving for factor, 417 * ln(factor) =~ (-2.30/5*loadav), or 418 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) = 419 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED 420 * 421 * Proof of (2): 422 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)): 423 * solving for power, 424 * power*ln(b/(b+1)) =~ -2.30, or 425 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED 426 * 427 * Actual power values for the implemented algorithm are as follows: 428 * loadav: 1 2 3 4 429 * power: 5.68 10.32 14.94 19.55 430 */ 431 432/* calculations for digital decay to forget 90% of usage in 5*loadav sec */ 433#define loadfactor(loadav) (2 * (loadav)) 434#define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE)) 435 436/* decay 95% of `ts_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */ 437static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 438SYSCTL_UINT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, 439 "Decay factor used for updating %CPU"); 440 441/* 442 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 443 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 444 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 445 * 446 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 447 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 448 * 449 * If you don't want to bother with the faster/more-accurate formula, you 450 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 451 * (more general) method of calculating the %age of CPU used by a process. 452 */ 453#define CCPU_SHIFT 11 454 455/* 456 * Recompute process priorities, every hz ticks. 457 * MP-safe, called without the Giant mutex. 458 */ 459/* ARGSUSED */ 460static void 461schedcpu(void) 462{ 463 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 464 struct thread *td; 465 struct proc *p; 466 struct td_sched *ts; 467 int awake; 468 469 sx_slock(&allproc_lock); 470 FOREACH_PROC_IN_SYSTEM(p) { 471 PROC_LOCK(p); 472 if (p->p_state == PRS_NEW) { 473 PROC_UNLOCK(p); 474 continue; 475 } 476 FOREACH_THREAD_IN_PROC(p, td) { 477 awake = 0; 478 ts = td_get_sched(td); 479 thread_lock(td); 480 /* 481 * Increment sleep time (if sleeping). We 482 * ignore overflow, as above. 483 */ 484 /* 485 * The td_sched slptimes are not touched in wakeup 486 * because the thread may not HAVE everything in 487 * memory? XXX I think this is out of date. 488 */ 489 if (TD_ON_RUNQ(td)) { 490 awake = 1; 491 td->td_flags &= ~TDF_DIDRUN; 492 } else if (TD_IS_RUNNING(td)) { 493 awake = 1; 494 /* Do not clear TDF_DIDRUN */ 495 } else if (td->td_flags & TDF_DIDRUN) { 496 awake = 1; 497 td->td_flags &= ~TDF_DIDRUN; 498 } 499 500 /* 501 * ts_pctcpu is only for ps and ttyinfo(). 502 */ 503 ts->ts_pctcpu = (ts->ts_pctcpu * ccpu) >> FSHIFT; 504 /* 505 * If the td_sched has been idle the entire second, 506 * stop recalculating its priority until 507 * it wakes up. 508 */ 509 if (ts->ts_cpticks != 0) { 510#if (FSHIFT >= CCPU_SHIFT) 511 ts->ts_pctcpu += (realstathz == 100) 512 ? ((fixpt_t) ts->ts_cpticks) << 513 (FSHIFT - CCPU_SHIFT) : 514 100 * (((fixpt_t) ts->ts_cpticks) 515 << (FSHIFT - CCPU_SHIFT)) / realstathz; 516#else 517 ts->ts_pctcpu += ((FSCALE - ccpu) * 518 (ts->ts_cpticks * 519 FSCALE / realstathz)) >> FSHIFT; 520#endif 521 ts->ts_cpticks = 0; 522 } 523 /* 524 * If there are ANY running threads in this process, 525 * then don't count it as sleeping. 526 * XXX: this is broken. 527 */ 528 if (awake) { 529 if (ts->ts_slptime > 1) { 530 /* 531 * In an ideal world, this should not 532 * happen, because whoever woke us 533 * up from the long sleep should have 534 * unwound the slptime and reset our 535 * priority before we run at the stale 536 * priority. Should KASSERT at some 537 * point when all the cases are fixed. 538 */ 539 updatepri(td); 540 } 541 ts->ts_slptime = 0; 542 } else 543 ts->ts_slptime++; 544 if (ts->ts_slptime > 1) { 545 thread_unlock(td); 546 continue; 547 } 548 ts->ts_estcpu = decay_cpu(loadfac, ts->ts_estcpu); 549 resetpriority(td); 550 resetpriority_thread(td); 551 thread_unlock(td); 552 } 553 PROC_UNLOCK(p); 554 } 555 sx_sunlock(&allproc_lock); 556} 557 558/* 559 * Main loop for a kthread that executes schedcpu once a second. 560 */ 561static void 562schedcpu_thread(void) 563{ 564 565 for (;;) { 566 schedcpu(); 567 pause("-", hz); 568 } 569} 570 571/* 572 * Recalculate the priority of a process after it has slept for a while. 573 * For all load averages >= 1 and max ts_estcpu of 255, sleeping for at 574 * least six times the loadfactor will decay ts_estcpu to zero. 575 */ 576static void 577updatepri(struct thread *td) 578{ 579 struct td_sched *ts; 580 fixpt_t loadfac; 581 unsigned int newcpu; 582 583 ts = td_get_sched(td); 584 loadfac = loadfactor(averunnable.ldavg[0]); 585 if (ts->ts_slptime > 5 * loadfac) 586 ts->ts_estcpu = 0; 587 else { 588 newcpu = ts->ts_estcpu; 589 ts->ts_slptime--; /* was incremented in schedcpu() */ 590 while (newcpu && --ts->ts_slptime) 591 newcpu = decay_cpu(loadfac, newcpu); 592 ts->ts_estcpu = newcpu; 593 } 594} 595 596/* 597 * Compute the priority of a process when running in user mode. 598 * Arrange to reschedule if the resulting priority is better 599 * than that of the current process. 600 */ 601static void 602resetpriority(struct thread *td) 603{ 604 u_int newpriority; 605 606 if (td->td_pri_class != PRI_TIMESHARE) 607 return; 608 newpriority = PUSER + 609 td_get_sched(td)->ts_estcpu / INVERSE_ESTCPU_WEIGHT + 610 NICE_WEIGHT * (td->td_proc->p_nice - PRIO_MIN); 611 newpriority = min(max(newpriority, PRI_MIN_TIMESHARE), 612 PRI_MAX_TIMESHARE); 613 sched_user_prio(td, newpriority); 614} 615 616/* 617 * Update the thread's priority when the associated process's user 618 * priority changes. 619 */ 620static void 621resetpriority_thread(struct thread *td) 622{ 623 624 /* Only change threads with a time sharing user priority. */ 625 if (td->td_priority < PRI_MIN_TIMESHARE || 626 td->td_priority > PRI_MAX_TIMESHARE) 627 return; 628 629 /* XXX the whole needresched thing is broken, but not silly. */ 630 maybe_resched(td); 631 632 sched_prio(td, td->td_user_pri); 633} 634 635/* ARGSUSED */ 636static void 637sched_setup(void *dummy) 638{ 639 640 setup_runqs(); 641 642 /* Account for thread0. */ 643 sched_load_add(); 644} 645 646/* 647 * This routine determines time constants after stathz and hz are setup. 648 */ 649static void 650sched_initticks(void *dummy) 651{ 652 653 realstathz = stathz ? stathz : hz; 654 sched_slice = realstathz / 10; /* ~100ms */ 655 hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) / 656 realstathz); 657} 658 659/* External interfaces start here */ 660 661/* 662 * Very early in the boot some setup of scheduler-specific 663 * parts of proc0 and of some scheduler resources needs to be done. 664 * Called from: 665 * proc0_init() 666 */ 667void 668schedinit(void) 669{ 670 671 /* 672 * Set up the scheduler specific parts of thread0. 673 */ 674 thread0.td_lock = &sched_lock; 675 td_get_sched(&thread0)->ts_slice = sched_slice; 676 mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN); 677} 678 679void 680schedinit_ap(void) 681{ 682 683 /* Nothing needed. */ 684} 685 686int 687sched_runnable(void) 688{ 689#ifdef SMP 690 return runq_check(&runq) + runq_check(&runq_pcpu[PCPU_GET(cpuid)]); 691#else 692 return runq_check(&runq); 693#endif 694} 695 696int 697sched_rr_interval(void) 698{ 699 700 /* Convert sched_slice from stathz to hz. */ 701 return (imax(1, (sched_slice * hz + realstathz / 2) / realstathz)); 702} 703 704SCHED_STAT_DEFINE(ithread_demotions, "Interrupt thread priority demotions"); 705SCHED_STAT_DEFINE(ithread_preemptions, 706 "Interrupt thread preemptions due to time-sharing"); 707 708/* 709 * We adjust the priority of the current process. The priority of a 710 * process gets worse as it accumulates CPU time. The cpu usage 711 * estimator (ts_estcpu) is increased here. resetpriority() will 712 * compute a different priority each time ts_estcpu increases by 713 * INVERSE_ESTCPU_WEIGHT (until PRI_MAX_TIMESHARE is reached). The 714 * cpu usage estimator ramps up quite quickly when the process is 715 * running (linearly), and decays away exponentially, at a rate which 716 * is proportionally slower when the system is busy. The basic 717 * principle is that the system will 90% forget that the process used 718 * a lot of CPU time in 5 * loadav seconds. This causes the system to 719 * favor processes which haven't run much recently, and to round-robin 720 * among other processes. 721 */ 722static void 723sched_clock_tick(struct thread *td) 724{ 725 struct pcpuidlestat *stat; 726 struct td_sched *ts; 727 728 THREAD_LOCK_ASSERT(td, MA_OWNED); 729 ts = td_get_sched(td); 730 731 ts->ts_cpticks++; 732 ts->ts_estcpu = ESTCPULIM(ts->ts_estcpu + 1); 733 if ((ts->ts_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) { 734 resetpriority(td); 735 resetpriority_thread(td); 736 } 737 738 /* 739 * Force a context switch if the current thread has used up a full 740 * time slice (default is 100ms). 741 */ 742 if (!TD_IS_IDLETHREAD(td) && --ts->ts_slice <= 0) { 743 ts->ts_slice = sched_slice; 744 745 /* 746 * If an ithread uses a full quantum, demote its 747 * priority and preempt it. 748 */ 749 if (PRI_BASE(td->td_pri_class) == PRI_ITHD) { 750 SCHED_STAT_INC(ithread_preemptions); 751 td->td_owepreempt = 1; 752 if (td->td_base_pri + RQ_PPQ < PRI_MAX_ITHD) { 753 SCHED_STAT_INC(ithread_demotions); 754 sched_prio(td, td->td_base_pri + RQ_PPQ); 755 } 756 } else { 757 td->td_flags |= TDF_SLICEEND; 758 ast_sched_locked(td, TDA_SCHED); 759 } 760 } 761 762 stat = DPCPU_PTR(idlestat); 763 stat->oldidlecalls = stat->idlecalls; 764 stat->idlecalls = 0; 765} 766 767void 768sched_clock(struct thread *td, int cnt) 769{ 770 771 for ( ; cnt > 0; cnt--) 772 sched_clock_tick(td); 773} 774 775/* 776 * Charge child's scheduling CPU usage to parent. 777 */ 778void 779sched_exit(struct proc *p, struct thread *td) 780{ 781 782 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "proc exit", 783 "prio:%d", td->td_priority); 784 785 PROC_LOCK_ASSERT(p, MA_OWNED); 786 sched_exit_thread(FIRST_THREAD_IN_PROC(p), td); 787} 788 789void 790sched_exit_thread(struct thread *td, struct thread *child) 791{ 792 793 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "exit", 794 "prio:%d", child->td_priority); 795 thread_lock(td); 796 td_get_sched(td)->ts_estcpu = ESTCPULIM(td_get_sched(td)->ts_estcpu + 797 td_get_sched(child)->ts_estcpu); 798 thread_unlock(td); 799 thread_lock(child); 800 if ((child->td_flags & TDF_NOLOAD) == 0) 801 sched_load_rem(); 802 thread_unlock(child); 803} 804 805void 806sched_fork(struct thread *td, struct thread *childtd) 807{ 808 sched_fork_thread(td, childtd); 809} 810 811void 812sched_fork_thread(struct thread *td, struct thread *childtd) 813{ 814 struct td_sched *ts, *tsc; 815 816 childtd->td_oncpu = NOCPU; 817 childtd->td_lastcpu = NOCPU; 818 childtd->td_lock = &sched_lock; 819 childtd->td_cpuset = cpuset_ref(td->td_cpuset); 820 childtd->td_domain.dr_policy = td->td_cpuset->cs_domain; 821 childtd->td_priority = childtd->td_base_pri; 822 ts = td_get_sched(childtd); 823 bzero(ts, sizeof(*ts)); 824 tsc = td_get_sched(td); 825 ts->ts_estcpu = tsc->ts_estcpu; 826 ts->ts_flags |= (tsc->ts_flags & TSF_AFFINITY); 827 ts->ts_slice = 1; 828} 829 830void 831sched_nice(struct proc *p, int nice) 832{ 833 struct thread *td; 834 835 PROC_LOCK_ASSERT(p, MA_OWNED); 836 p->p_nice = nice; 837 FOREACH_THREAD_IN_PROC(p, td) { 838 thread_lock(td); 839 resetpriority(td); 840 resetpriority_thread(td); 841 thread_unlock(td); 842 } 843} 844 845void 846sched_class(struct thread *td, int class) 847{ 848 THREAD_LOCK_ASSERT(td, MA_OWNED); 849 td->td_pri_class = class; 850} 851 852/* 853 * Adjust the priority of a thread. 854 */ 855static void 856sched_priority(struct thread *td, u_char prio) 857{ 858 859 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "priority change", 860 "prio:%d", td->td_priority, "new prio:%d", prio, KTR_ATTR_LINKED, 861 sched_tdname(curthread)); 862 SDT_PROBE3(sched, , , change__pri, td, td->td_proc, prio); 863 if (td != curthread && prio > td->td_priority) { 864 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread), 865 "lend prio", "prio:%d", td->td_priority, "new prio:%d", 866 prio, KTR_ATTR_LINKED, sched_tdname(td)); 867 SDT_PROBE4(sched, , , lend__pri, td, td->td_proc, prio, 868 curthread); 869 } 870 THREAD_LOCK_ASSERT(td, MA_OWNED); 871 if (td->td_priority == prio) 872 return; 873 td->td_priority = prio; 874 if (TD_ON_RUNQ(td) && td->td_rqindex != (prio / RQ_PPQ)) { 875 sched_rem(td); 876 sched_add(td, SRQ_BORING | SRQ_HOLDTD); 877 } 878} 879 880/* 881 * Update a thread's priority when it is lent another thread's 882 * priority. 883 */ 884void 885sched_lend_prio(struct thread *td, u_char prio) 886{ 887 888 td->td_flags |= TDF_BORROWING; 889 sched_priority(td, prio); 890} 891 892/* 893 * Restore a thread's priority when priority propagation is 894 * over. The prio argument is the minimum priority the thread 895 * needs to have to satisfy other possible priority lending 896 * requests. If the thread's regulary priority is less 897 * important than prio the thread will keep a priority boost 898 * of prio. 899 */ 900void 901sched_unlend_prio(struct thread *td, u_char prio) 902{ 903 u_char base_pri; 904 905 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 906 td->td_base_pri <= PRI_MAX_TIMESHARE) 907 base_pri = td->td_user_pri; 908 else 909 base_pri = td->td_base_pri; 910 if (prio >= base_pri) { 911 td->td_flags &= ~TDF_BORROWING; 912 sched_prio(td, base_pri); 913 } else 914 sched_lend_prio(td, prio); 915} 916 917void 918sched_prio(struct thread *td, u_char prio) 919{ 920 u_char oldprio; 921 922 /* First, update the base priority. */ 923 td->td_base_pri = prio; 924 925 /* 926 * If the thread is borrowing another thread's priority, don't ever 927 * lower the priority. 928 */ 929 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 930 return; 931 932 /* Change the real priority. */ 933 oldprio = td->td_priority; 934 sched_priority(td, prio); 935 936 /* 937 * If the thread is on a turnstile, then let the turnstile update 938 * its state. 939 */ 940 if (TD_ON_LOCK(td) && oldprio != prio) 941 turnstile_adjust(td, oldprio); 942} 943 944void 945sched_ithread_prio(struct thread *td, u_char prio) 946{ 947 THREAD_LOCK_ASSERT(td, MA_OWNED); 948 MPASS(td->td_pri_class == PRI_ITHD); 949 td->td_base_ithread_pri = prio; 950 sched_prio(td, prio); 951} 952 953void 954sched_user_prio(struct thread *td, u_char prio) 955{ 956 957 THREAD_LOCK_ASSERT(td, MA_OWNED); 958 td->td_base_user_pri = prio; 959 if (td->td_lend_user_pri <= prio) 960 return; 961 td->td_user_pri = prio; 962} 963 964void 965sched_lend_user_prio(struct thread *td, u_char prio) 966{ 967 968 THREAD_LOCK_ASSERT(td, MA_OWNED); 969 td->td_lend_user_pri = prio; 970 td->td_user_pri = min(prio, td->td_base_user_pri); 971 if (td->td_priority > td->td_user_pri) 972 sched_prio(td, td->td_user_pri); 973 else if (td->td_priority != td->td_user_pri) 974 ast_sched_locked(td, TDA_SCHED); 975} 976 977/* 978 * Like the above but first check if there is anything to do. 979 */ 980void 981sched_lend_user_prio_cond(struct thread *td, u_char prio) 982{ 983 984 if (td->td_lend_user_pri == prio) 985 return; 986 987 thread_lock(td); 988 sched_lend_user_prio(td, prio); 989 thread_unlock(td); 990} 991 992void 993sched_sleep(struct thread *td, int pri) 994{ 995 996 THREAD_LOCK_ASSERT(td, MA_OWNED); 997 td->td_slptick = ticks; 998 td_get_sched(td)->ts_slptime = 0; 999 if (pri != 0 && PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 1000 sched_prio(td, pri); 1001 if (TD_IS_SUSPENDED(td) || pri >= PSOCK) 1002 td->td_flags |= TDF_CANSWAP; 1003} 1004 1005void 1006sched_switch(struct thread *td, int flags) 1007{ 1008 struct thread *newtd; 1009 struct mtx *tmtx; 1010 int preempted; 1011 1012 tmtx = &sched_lock; 1013 1014 THREAD_LOCK_ASSERT(td, MA_OWNED); 1015 1016 td->td_lastcpu = td->td_oncpu; 1017 preempted = (td->td_flags & TDF_SLICEEND) == 0 && 1018 (flags & SW_PREEMPT) != 0; 1019 td->td_flags &= ~TDF_SLICEEND; 1020 ast_unsched_locked(td, TDA_SCHED); 1021 td->td_owepreempt = 0; 1022 td->td_oncpu = NOCPU; 1023 1024 /* 1025 * At the last moment, if this thread is still marked RUNNING, 1026 * then put it back on the run queue as it has not been suspended 1027 * or stopped or any thing else similar. We never put the idle 1028 * threads on the run queue, however. 1029 */ 1030 if (td->td_flags & TDF_IDLETD) { 1031 TD_SET_CAN_RUN(td); 1032#ifdef SMP 1033 CPU_CLR(PCPU_GET(cpuid), &idle_cpus_mask); 1034#endif 1035 } else { 1036 if (TD_IS_RUNNING(td)) { 1037 /* Put us back on the run queue. */ 1038 sched_add(td, SRQ_HOLDTD | SRQ_OURSELF | SRQ_YIELDING | 1039 (preempted ? SRQ_PREEMPTED : 0)); 1040 } 1041 } 1042 1043 /* 1044 * Switch to the sched lock to fix things up and pick 1045 * a new thread. Block the td_lock in order to avoid 1046 * breaking the critical path. 1047 */ 1048 if (td->td_lock != &sched_lock) { 1049 mtx_lock_spin(&sched_lock); 1050 tmtx = thread_lock_block(td); 1051 mtx_unlock_spin(tmtx); 1052 } 1053 1054 if ((td->td_flags & TDF_NOLOAD) == 0) 1055 sched_load_rem(); 1056 1057 newtd = choosethread(); 1058 MPASS(newtd->td_lock == &sched_lock); 1059 1060#if (KTR_COMPILE & KTR_SCHED) != 0 1061 if (TD_IS_IDLETHREAD(td)) 1062 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "idle", 1063 "prio:%d", td->td_priority); 1064 else 1065 KTR_STATE3(KTR_SCHED, "thread", sched_tdname(td), KTDSTATE(td), 1066 "prio:%d", td->td_priority, "wmesg:\"%s\"", td->td_wmesg, 1067 "lockname:\"%s\"", td->td_lockname); 1068#endif 1069 1070 if (td != newtd) { 1071#ifdef HWPMC_HOOKS 1072 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1073 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1074#endif 1075 1076 SDT_PROBE2(sched, , , off__cpu, newtd, newtd->td_proc); 1077 1078 /* I feel sleepy */ 1079 lock_profile_release_lock(&sched_lock.lock_object, true); 1080#ifdef KDTRACE_HOOKS 1081 /* 1082 * If DTrace has set the active vtime enum to anything 1083 * other than INACTIVE (0), then it should have set the 1084 * function to call. 1085 */ 1086 if (dtrace_vtime_active) 1087 (*dtrace_vtime_switch_func)(newtd); 1088#endif 1089 1090 cpu_switch(td, newtd, tmtx); 1091 lock_profile_obtain_lock_success(&sched_lock.lock_object, true, 1092 0, 0, __FILE__, __LINE__); 1093 /* 1094 * Where am I? What year is it? 1095 * We are in the same thread that went to sleep above, 1096 * but any amount of time may have passed. All our context 1097 * will still be available as will local variables. 1098 * PCPU values however may have changed as we may have 1099 * changed CPU so don't trust cached values of them. 1100 * New threads will go to fork_exit() instead of here 1101 * so if you change things here you may need to change 1102 * things there too. 1103 * 1104 * If the thread above was exiting it will never wake 1105 * up again here, so either it has saved everything it 1106 * needed to, or the thread_wait() or wait() will 1107 * need to reap it. 1108 */ 1109 1110 SDT_PROBE0(sched, , , on__cpu); 1111#ifdef HWPMC_HOOKS 1112 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1113 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1114#endif 1115 } else { 1116 td->td_lock = &sched_lock; 1117 SDT_PROBE0(sched, , , remain__cpu); 1118 } 1119 1120 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running", 1121 "prio:%d", td->td_priority); 1122 1123#ifdef SMP 1124 if (td->td_flags & TDF_IDLETD) 1125 CPU_SET(PCPU_GET(cpuid), &idle_cpus_mask); 1126#endif 1127 sched_lock.mtx_lock = (uintptr_t)td; 1128 td->td_oncpu = PCPU_GET(cpuid); 1129 spinlock_enter(); 1130 mtx_unlock_spin(&sched_lock); 1131} 1132 1133void 1134sched_wakeup(struct thread *td, int srqflags) 1135{ 1136 struct td_sched *ts; 1137 1138 THREAD_LOCK_ASSERT(td, MA_OWNED); 1139 ts = td_get_sched(td); 1140 td->td_flags &= ~TDF_CANSWAP; 1141 if (ts->ts_slptime > 1) { 1142 updatepri(td); 1143 resetpriority(td); 1144 } 1145 td->td_slptick = 0; 1146 ts->ts_slptime = 0; 1147 ts->ts_slice = sched_slice; 1148 1149 /* 1150 * When resuming an idle ithread, restore its base ithread 1151 * priority. 1152 */ 1153 if (PRI_BASE(td->td_pri_class) == PRI_ITHD && 1154 td->td_base_pri != td->td_base_ithread_pri) 1155 sched_prio(td, td->td_base_ithread_pri); 1156 1157 sched_add(td, srqflags); 1158} 1159 1160#ifdef SMP 1161static int 1162forward_wakeup(int cpunum) 1163{ 1164 struct pcpu *pc; 1165 cpuset_t dontuse, map, map2; 1166 u_int id, me; 1167 int iscpuset; 1168 1169 mtx_assert(&sched_lock, MA_OWNED); 1170 1171 CTR0(KTR_RUNQ, "forward_wakeup()"); 1172 1173 if ((!forward_wakeup_enabled) || 1174 (forward_wakeup_use_mask == 0 && forward_wakeup_use_loop == 0)) 1175 return (0); 1176 if (!smp_started || KERNEL_PANICKED()) 1177 return (0); 1178 1179 forward_wakeups_requested++; 1180 1181 /* 1182 * Check the idle mask we received against what we calculated 1183 * before in the old version. 1184 */ 1185 me = PCPU_GET(cpuid); 1186 1187 /* Don't bother if we should be doing it ourself. */ 1188 if (CPU_ISSET(me, &idle_cpus_mask) && 1189 (cpunum == NOCPU || me == cpunum)) 1190 return (0); 1191 1192 CPU_SETOF(me, &dontuse); 1193 CPU_OR(&dontuse, &dontuse, &stopped_cpus); 1194 CPU_OR(&dontuse, &dontuse, &hlt_cpus_mask); 1195 CPU_ZERO(&map2); 1196 if (forward_wakeup_use_loop) { 1197 STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) { 1198 id = pc->pc_cpuid; 1199 if (!CPU_ISSET(id, &dontuse) && 1200 pc->pc_curthread == pc->pc_idlethread) { 1201 CPU_SET(id, &map2); 1202 } 1203 } 1204 } 1205 1206 if (forward_wakeup_use_mask) { 1207 map = idle_cpus_mask; 1208 CPU_ANDNOT(&map, &map, &dontuse); 1209 1210 /* If they are both on, compare and use loop if different. */ 1211 if (forward_wakeup_use_loop) { 1212 if (CPU_CMP(&map, &map2)) { 1213 printf("map != map2, loop method preferred\n"); 1214 map = map2; 1215 } 1216 } 1217 } else { 1218 map = map2; 1219 } 1220 1221 /* If we only allow a specific CPU, then mask off all the others. */ 1222 if (cpunum != NOCPU) { 1223 KASSERT((cpunum <= mp_maxcpus),("forward_wakeup: bad cpunum.")); 1224 iscpuset = CPU_ISSET(cpunum, &map); 1225 if (iscpuset == 0) 1226 CPU_ZERO(&map); 1227 else 1228 CPU_SETOF(cpunum, &map); 1229 } 1230 if (!CPU_EMPTY(&map)) { 1231 forward_wakeups_delivered++; 1232 STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) { 1233 id = pc->pc_cpuid; 1234 if (!CPU_ISSET(id, &map)) 1235 continue; 1236 if (cpu_idle_wakeup(pc->pc_cpuid)) 1237 CPU_CLR(id, &map); 1238 } 1239 if (!CPU_EMPTY(&map)) 1240 ipi_selected(map, IPI_AST); 1241 return (1); 1242 } 1243 if (cpunum == NOCPU) 1244 printf("forward_wakeup: Idle processor not found\n"); 1245 return (0); 1246} 1247 1248static void 1249kick_other_cpu(int pri, int cpuid) 1250{ 1251 struct pcpu *pcpu; 1252 int cpri; 1253 1254 pcpu = pcpu_find(cpuid); 1255 if (CPU_ISSET(cpuid, &idle_cpus_mask)) { 1256 forward_wakeups_delivered++; 1257 if (!cpu_idle_wakeup(cpuid)) 1258 ipi_cpu(cpuid, IPI_AST); 1259 return; 1260 } 1261 1262 cpri = pcpu->pc_curthread->td_priority; 1263 if (pri >= cpri) 1264 return; 1265 1266#if defined(IPI_PREEMPTION) && defined(PREEMPTION) 1267#if !defined(FULL_PREEMPTION) 1268 if (pri <= PRI_MAX_ITHD) 1269#endif /* ! FULL_PREEMPTION */ 1270 { 1271 ipi_cpu(cpuid, IPI_PREEMPT); 1272 return; 1273 } 1274#endif /* defined(IPI_PREEMPTION) && defined(PREEMPTION) */ 1275 1276 if (pcpu->pc_curthread->td_lock == &sched_lock) { 1277 ast_sched_locked(pcpu->pc_curthread, TDA_SCHED); 1278 ipi_cpu(cpuid, IPI_AST); 1279 } 1280} 1281#endif /* SMP */ 1282 1283#ifdef SMP 1284static int 1285sched_pickcpu(struct thread *td) 1286{ 1287 int best, cpu; 1288 1289 mtx_assert(&sched_lock, MA_OWNED); 1290 1291 if (td->td_lastcpu != NOCPU && THREAD_CAN_SCHED(td, td->td_lastcpu)) 1292 best = td->td_lastcpu; 1293 else 1294 best = NOCPU; 1295 CPU_FOREACH(cpu) { 1296 if (!THREAD_CAN_SCHED(td, cpu)) 1297 continue; 1298 1299 if (best == NOCPU) 1300 best = cpu; 1301 else if (runq_length[cpu] < runq_length[best]) 1302 best = cpu; 1303 } 1304 KASSERT(best != NOCPU, ("no valid CPUs")); 1305 1306 return (best); 1307} 1308#endif 1309 1310void 1311sched_add(struct thread *td, int flags) 1312#ifdef SMP 1313{ 1314 cpuset_t tidlemsk; 1315 struct td_sched *ts; 1316 u_int cpu, cpuid; 1317 int forwarded = 0; 1318 int single_cpu = 0; 1319 1320 ts = td_get_sched(td); 1321 THREAD_LOCK_ASSERT(td, MA_OWNED); 1322 KASSERT((td->td_inhibitors == 0), 1323 ("sched_add: trying to run inhibited thread")); 1324 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 1325 ("sched_add: bad thread state")); 1326 KASSERT(td->td_flags & TDF_INMEM, 1327 ("sched_add: thread swapped out")); 1328 1329 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add", 1330 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 1331 sched_tdname(curthread)); 1332 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup", 1333 KTR_ATTR_LINKED, sched_tdname(td)); 1334 SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL, 1335 flags & SRQ_PREEMPTED); 1336 1337 /* 1338 * Now that the thread is moving to the run-queue, set the lock 1339 * to the scheduler's lock. 1340 */ 1341 if (td->td_lock != &sched_lock) { 1342 mtx_lock_spin(&sched_lock); 1343 if ((flags & SRQ_HOLD) != 0) 1344 td->td_lock = &sched_lock; 1345 else 1346 thread_lock_set(td, &sched_lock); 1347 } 1348 TD_SET_RUNQ(td); 1349 1350 /* 1351 * If SMP is started and the thread is pinned or otherwise limited to 1352 * a specific set of CPUs, queue the thread to a per-CPU run queue. 1353 * Otherwise, queue the thread to the global run queue. 1354 * 1355 * If SMP has not yet been started we must use the global run queue 1356 * as per-CPU state may not be initialized yet and we may crash if we 1357 * try to access the per-CPU run queues. 1358 */ 1359 if (smp_started && (td->td_pinned != 0 || td->td_flags & TDF_BOUND || 1360 ts->ts_flags & TSF_AFFINITY)) { 1361 if (td->td_pinned != 0) 1362 cpu = td->td_lastcpu; 1363 else if (td->td_flags & TDF_BOUND) { 1364 /* Find CPU from bound runq. */ 1365 KASSERT(SKE_RUNQ_PCPU(ts), 1366 ("sched_add: bound td_sched not on cpu runq")); 1367 cpu = ts->ts_runq - &runq_pcpu[0]; 1368 } else 1369 /* Find a valid CPU for our cpuset */ 1370 cpu = sched_pickcpu(td); 1371 ts->ts_runq = &runq_pcpu[cpu]; 1372 single_cpu = 1; 1373 CTR3(KTR_RUNQ, 1374 "sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td, 1375 cpu); 1376 } else { 1377 CTR2(KTR_RUNQ, 1378 "sched_add: adding td_sched:%p (td:%p) to gbl runq", ts, 1379 td); 1380 cpu = NOCPU; 1381 ts->ts_runq = &runq; 1382 } 1383 1384 if ((td->td_flags & TDF_NOLOAD) == 0) 1385 sched_load_add(); 1386 runq_add(ts->ts_runq, td, flags); 1387 if (cpu != NOCPU) 1388 runq_length[cpu]++; 1389 1390 cpuid = PCPU_GET(cpuid); 1391 if (single_cpu && cpu != cpuid) { 1392 kick_other_cpu(td->td_priority, cpu); 1393 } else { 1394 if (!single_cpu) { 1395 tidlemsk = idle_cpus_mask; 1396 CPU_ANDNOT(&tidlemsk, &tidlemsk, &hlt_cpus_mask); 1397 CPU_CLR(cpuid, &tidlemsk); 1398 1399 if (!CPU_ISSET(cpuid, &idle_cpus_mask) && 1400 ((flags & SRQ_INTR) == 0) && 1401 !CPU_EMPTY(&tidlemsk)) 1402 forwarded = forward_wakeup(cpu); 1403 } 1404 1405 if (!forwarded) { 1406 if (!maybe_preempt(td)) 1407 maybe_resched(td); 1408 } 1409 } 1410 if ((flags & SRQ_HOLDTD) == 0) 1411 thread_unlock(td); 1412} 1413#else /* SMP */ 1414{ 1415 struct td_sched *ts; 1416 1417 ts = td_get_sched(td); 1418 THREAD_LOCK_ASSERT(td, MA_OWNED); 1419 KASSERT((td->td_inhibitors == 0), 1420 ("sched_add: trying to run inhibited thread")); 1421 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 1422 ("sched_add: bad thread state")); 1423 KASSERT(td->td_flags & TDF_INMEM, 1424 ("sched_add: thread swapped out")); 1425 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add", 1426 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 1427 sched_tdname(curthread)); 1428 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup", 1429 KTR_ATTR_LINKED, sched_tdname(td)); 1430 SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL, 1431 flags & SRQ_PREEMPTED); 1432 1433 /* 1434 * Now that the thread is moving to the run-queue, set the lock 1435 * to the scheduler's lock. 1436 */ 1437 if (td->td_lock != &sched_lock) { 1438 mtx_lock_spin(&sched_lock); 1439 if ((flags & SRQ_HOLD) != 0) 1440 td->td_lock = &sched_lock; 1441 else 1442 thread_lock_set(td, &sched_lock); 1443 } 1444 TD_SET_RUNQ(td); 1445 CTR2(KTR_RUNQ, "sched_add: adding td_sched:%p (td:%p) to runq", ts, td); 1446 ts->ts_runq = &runq; 1447 1448 if ((td->td_flags & TDF_NOLOAD) == 0) 1449 sched_load_add(); 1450 runq_add(ts->ts_runq, td, flags); 1451 if (!maybe_preempt(td)) 1452 maybe_resched(td); 1453 if ((flags & SRQ_HOLDTD) == 0) 1454 thread_unlock(td); 1455} 1456#endif /* SMP */ 1457 1458void 1459sched_rem(struct thread *td) 1460{ 1461 struct td_sched *ts; 1462 1463 ts = td_get_sched(td); 1464 KASSERT(td->td_flags & TDF_INMEM, 1465 ("sched_rem: thread swapped out")); 1466 KASSERT(TD_ON_RUNQ(td), 1467 ("sched_rem: thread not on run queue")); 1468 mtx_assert(&sched_lock, MA_OWNED); 1469 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq rem", 1470 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 1471 sched_tdname(curthread)); 1472 SDT_PROBE3(sched, , , dequeue, td, td->td_proc, NULL); 1473 1474 if ((td->td_flags & TDF_NOLOAD) == 0) 1475 sched_load_rem(); 1476#ifdef SMP 1477 if (ts->ts_runq != &runq) 1478 runq_length[ts->ts_runq - runq_pcpu]--; 1479#endif 1480 runq_remove(ts->ts_runq, td); 1481 TD_SET_CAN_RUN(td); 1482} 1483 1484/* 1485 * Select threads to run. Note that running threads still consume a 1486 * slot. 1487 */ 1488struct thread * 1489sched_choose(void) 1490{ 1491 struct thread *td; 1492 struct runq *rq; 1493 1494 mtx_assert(&sched_lock, MA_OWNED); 1495#ifdef SMP 1496 struct thread *tdcpu; 1497 1498 rq = &runq; 1499 td = runq_choose_fuzz(&runq, runq_fuzz); 1500 tdcpu = runq_choose(&runq_pcpu[PCPU_GET(cpuid)]); 1501 1502 if (td == NULL || 1503 (tdcpu != NULL && 1504 tdcpu->td_priority < td->td_priority)) { 1505 CTR2(KTR_RUNQ, "choosing td %p from pcpu runq %d", tdcpu, 1506 PCPU_GET(cpuid)); 1507 td = tdcpu; 1508 rq = &runq_pcpu[PCPU_GET(cpuid)]; 1509 } else { 1510 CTR1(KTR_RUNQ, "choosing td_sched %p from main runq", td); 1511 } 1512 1513#else 1514 rq = &runq; 1515 td = runq_choose(&runq); 1516#endif 1517 1518 if (td) { 1519#ifdef SMP 1520 if (td == tdcpu) 1521 runq_length[PCPU_GET(cpuid)]--; 1522#endif 1523 runq_remove(rq, td); 1524 td->td_flags |= TDF_DIDRUN; 1525 1526 KASSERT(td->td_flags & TDF_INMEM, 1527 ("sched_choose: thread swapped out")); 1528 return (td); 1529 } 1530 return (PCPU_GET(idlethread)); 1531} 1532 1533void 1534sched_preempt(struct thread *td) 1535{ 1536 int flags; 1537 1538 SDT_PROBE2(sched, , , surrender, td, td->td_proc); 1539 if (td->td_critnest > 1) { 1540 td->td_owepreempt = 1; 1541 } else { 1542 thread_lock(td); 1543 flags = SW_INVOL | SW_PREEMPT; 1544 flags |= TD_IS_IDLETHREAD(td) ? SWT_REMOTEWAKEIDLE : 1545 SWT_REMOTEPREEMPT; 1546 mi_switch(flags); 1547 } 1548} 1549 1550void 1551sched_userret_slowpath(struct thread *td) 1552{ 1553 1554 thread_lock(td); 1555 td->td_priority = td->td_user_pri; 1556 td->td_base_pri = td->td_user_pri; 1557 thread_unlock(td); 1558} 1559 1560void 1561sched_bind(struct thread *td, int cpu) 1562{ 1563#ifdef SMP 1564 struct td_sched *ts = td_get_sched(td); 1565#endif 1566 1567 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED); 1568 KASSERT(td == curthread, ("sched_bind: can only bind curthread")); 1569 1570 td->td_flags |= TDF_BOUND; 1571#ifdef SMP 1572 ts->ts_runq = &runq_pcpu[cpu]; 1573 if (PCPU_GET(cpuid) == cpu) 1574 return; 1575 1576 mi_switch(SW_VOL | SWT_BIND); 1577 thread_lock(td); 1578#endif 1579} 1580 1581void 1582sched_unbind(struct thread* td) 1583{ 1584 THREAD_LOCK_ASSERT(td, MA_OWNED); 1585 KASSERT(td == curthread, ("sched_unbind: can only bind curthread")); 1586 td->td_flags &= ~TDF_BOUND; 1587} 1588 1589int 1590sched_is_bound(struct thread *td) 1591{ 1592 THREAD_LOCK_ASSERT(td, MA_OWNED); 1593 return (td->td_flags & TDF_BOUND); 1594} 1595 1596void 1597sched_relinquish(struct thread *td) 1598{ 1599 thread_lock(td); 1600 mi_switch(SW_VOL | SWT_RELINQUISH); 1601} 1602 1603int 1604sched_load(void) 1605{ 1606 return (sched_tdcnt); 1607} 1608 1609int 1610sched_sizeof_proc(void) 1611{ 1612 return (sizeof(struct proc)); 1613} 1614 1615int 1616sched_sizeof_thread(void) 1617{ 1618 return (sizeof(struct thread) + sizeof(struct td_sched)); 1619} 1620 1621fixpt_t 1622sched_pctcpu(struct thread *td) 1623{ 1624 struct td_sched *ts; 1625 1626 THREAD_LOCK_ASSERT(td, MA_OWNED); 1627 ts = td_get_sched(td); 1628 return (ts->ts_pctcpu); 1629} 1630 1631#ifdef RACCT 1632/* 1633 * Calculates the contribution to the thread cpu usage for the latest 1634 * (unfinished) second. 1635 */ 1636fixpt_t 1637sched_pctcpu_delta(struct thread *td) 1638{ 1639 struct td_sched *ts; 1640 fixpt_t delta; 1641 int realstathz; 1642 1643 THREAD_LOCK_ASSERT(td, MA_OWNED); 1644 ts = td_get_sched(td); 1645 delta = 0; 1646 realstathz = stathz ? stathz : hz; 1647 if (ts->ts_cpticks != 0) { 1648#if (FSHIFT >= CCPU_SHIFT) 1649 delta = (realstathz == 100) 1650 ? ((fixpt_t) ts->ts_cpticks) << 1651 (FSHIFT - CCPU_SHIFT) : 1652 100 * (((fixpt_t) ts->ts_cpticks) 1653 << (FSHIFT - CCPU_SHIFT)) / realstathz; 1654#else 1655 delta = ((FSCALE - ccpu) * 1656 (ts->ts_cpticks * 1657 FSCALE / realstathz)) >> FSHIFT; 1658#endif 1659 } 1660 1661 return (delta); 1662} 1663#endif 1664 1665u_int 1666sched_estcpu(struct thread *td) 1667{ 1668 1669 return (td_get_sched(td)->ts_estcpu); 1670} 1671 1672/* 1673 * The actual idle process. 1674 */ 1675void 1676sched_idletd(void *dummy) 1677{ 1678 struct pcpuidlestat *stat; 1679 1680 THREAD_NO_SLEEPING(); 1681 stat = DPCPU_PTR(idlestat); 1682 for (;;) { 1683 mtx_assert(&Giant, MA_NOTOWNED); 1684 1685 while (sched_runnable() == 0) { 1686 cpu_idle(stat->idlecalls + stat->oldidlecalls > 64); 1687 stat->idlecalls++; 1688 } 1689 1690 mtx_lock_spin(&sched_lock); 1691 mi_switch(SW_VOL | SWT_IDLE); 1692 } 1693} 1694 1695static void 1696sched_throw_tail(struct thread *td) 1697{ 1698 1699 mtx_assert(&sched_lock, MA_OWNED); 1700 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 1701 cpu_throw(td, choosethread()); /* doesn't return */ 1702} 1703 1704/* 1705 * A CPU is entering for the first time. 1706 */ 1707void 1708sched_ap_entry(void) 1709{ 1710 1711 /* 1712 * Correct spinlock nesting. The idle thread context that we are 1713 * borrowing was created so that it would start out with a single 1714 * spin lock (sched_lock) held in fork_trampoline(). Since we've 1715 * explicitly acquired locks in this function, the nesting count 1716 * is now 2 rather than 1. Since we are nested, calling 1717 * spinlock_exit() will simply adjust the counts without allowing 1718 * spin lock using code to interrupt us. 1719 */ 1720 mtx_lock_spin(&sched_lock); 1721 spinlock_exit(); 1722 PCPU_SET(switchtime, cpu_ticks()); 1723 PCPU_SET(switchticks, ticks); 1724 1725 sched_throw_tail(NULL); 1726} 1727 1728/* 1729 * A thread is exiting. 1730 */ 1731void 1732sched_throw(struct thread *td) 1733{ 1734 1735 MPASS(td != NULL); 1736 MPASS(td->td_lock == &sched_lock); 1737 1738 lock_profile_release_lock(&sched_lock.lock_object, true); 1739 td->td_lastcpu = td->td_oncpu; 1740 td->td_oncpu = NOCPU; 1741 1742 sched_throw_tail(td); 1743} 1744 1745void 1746sched_fork_exit(struct thread *td) 1747{ 1748 1749 /* 1750 * Finish setting up thread glue so that it begins execution in a 1751 * non-nested critical section with sched_lock held but not recursed. 1752 */ 1753 td->td_oncpu = PCPU_GET(cpuid); 1754 sched_lock.mtx_lock = (uintptr_t)td; 1755 lock_profile_obtain_lock_success(&sched_lock.lock_object, true, 1756 0, 0, __FILE__, __LINE__); 1757 THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED); 1758 1759 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running", 1760 "prio:%d", td->td_priority); 1761 SDT_PROBE0(sched, , , on__cpu); 1762} 1763 1764char * 1765sched_tdname(struct thread *td) 1766{ 1767#ifdef KTR 1768 struct td_sched *ts; 1769 1770 ts = td_get_sched(td); 1771 if (ts->ts_name[0] == '\0') 1772 snprintf(ts->ts_name, sizeof(ts->ts_name), 1773 "%s tid %d", td->td_name, td->td_tid); 1774 return (ts->ts_name); 1775#else 1776 return (td->td_name); 1777#endif 1778} 1779 1780#ifdef KTR 1781void 1782sched_clear_tdname(struct thread *td) 1783{ 1784 struct td_sched *ts; 1785 1786 ts = td_get_sched(td); 1787 ts->ts_name[0] = '\0'; 1788} 1789#endif 1790 1791void 1792sched_affinity(struct thread *td) 1793{ 1794#ifdef SMP 1795 struct td_sched *ts; 1796 int cpu; 1797 1798 THREAD_LOCK_ASSERT(td, MA_OWNED); 1799 1800 /* 1801 * Set the TSF_AFFINITY flag if there is at least one CPU this 1802 * thread can't run on. 1803 */ 1804 ts = td_get_sched(td); 1805 ts->ts_flags &= ~TSF_AFFINITY; 1806 CPU_FOREACH(cpu) { 1807 if (!THREAD_CAN_SCHED(td, cpu)) { 1808 ts->ts_flags |= TSF_AFFINITY; 1809 break; 1810 } 1811 } 1812 1813 /* 1814 * If this thread can run on all CPUs, nothing else to do. 1815 */ 1816 if (!(ts->ts_flags & TSF_AFFINITY)) 1817 return; 1818 1819 /* Pinned threads and bound threads should be left alone. */ 1820 if (td->td_pinned != 0 || td->td_flags & TDF_BOUND) 1821 return; 1822 1823 switch (TD_GET_STATE(td)) { 1824 case TDS_RUNQ: 1825 /* 1826 * If we are on a per-CPU runqueue that is in the set, 1827 * then nothing needs to be done. 1828 */ 1829 if (ts->ts_runq != &runq && 1830 THREAD_CAN_SCHED(td, ts->ts_runq - runq_pcpu)) 1831 return; 1832 1833 /* Put this thread on a valid per-CPU runqueue. */ 1834 sched_rem(td); 1835 sched_add(td, SRQ_HOLDTD | SRQ_BORING); 1836 break; 1837 case TDS_RUNNING: 1838 /* 1839 * See if our current CPU is in the set. If not, force a 1840 * context switch. 1841 */ 1842 if (THREAD_CAN_SCHED(td, td->td_oncpu)) 1843 return; 1844 1845 ast_sched_locked(td, TDA_SCHED); 1846 if (td != curthread) 1847 ipi_cpu(cpu, IPI_AST); 1848 break; 1849 default: 1850 break; 1851 } 1852#endif 1853} 1854