1 /*- 2 * Copyright (c) 1982, 1986, 1990, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include "opt_hwpmc_hooks.h" 39 #include "opt_sched.h" 40 #include "opt_kdtrace.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/cpuset.h> 45 #include <sys/kernel.h> 46 #include <sys/ktr.h> 47 #include <sys/lock.h> 48 #include <sys/kthread.h> 49 #include <sys/mutex.h> 50 #include <sys/proc.h> 51 #include <sys/resourcevar.h> 52 #include <sys/sched.h> 53 #include <sys/smp.h> 54 #include <sys/sysctl.h> 55 #include <sys/sx.h> 56 #include <sys/turnstile.h> 57 #include <sys/umtx.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> 67 int dtrace_vtime_active; 68 dtrace_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 /* 86 * The schedulable entity that runs a context. 87 * This is an extension to the thread structure and is tailored to 88 * the requirements of this scheduler 89 */ 90 struct td_sched { 91 fixpt_t ts_pctcpu; /* (j) %cpu during p_swtime. */ 92 int ts_cpticks; /* (j) Ticks of cpu time. */ 93 int ts_slptime; /* (j) Seconds !RUNNING. */ 94 struct runq *ts_runq; /* runq the thread is currently on */ 95 }; 96 97 /* flags kept in td_flags */ 98 #define TDF_DIDRUN TDF_SCHED0 /* thread actually ran. */ 99 #define TDF_BOUND TDF_SCHED1 /* Bound to one CPU. */ 100 101 #define SKE_RUNQ_PCPU(ts) \ 102 ((ts)->ts_runq != 0 && (ts)->ts_runq != &runq) 103 104 static struct td_sched td_sched0; 105 struct mtx sched_lock; 106 107 static int sched_tdcnt; /* Total runnable threads in the system. */ 108 static int sched_quantum; /* Roundrobin scheduling quantum in ticks. */ 109 #define SCHED_QUANTUM (hz / 10) /* Default sched quantum */ 110 111 static void setup_runqs(void); 112 static void schedcpu(void); 113 static void schedcpu_thread(void); 114 static void sched_priority(struct thread *td, u_char prio); 115 static void sched_setup(void *dummy); 116 static void maybe_resched(struct thread *td); 117 static void updatepri(struct thread *td); 118 static void resetpriority(struct thread *td); 119 static void resetpriority_thread(struct thread *td); 120 #ifdef SMP 121 static int forward_wakeup(int cpunum); 122 #endif 123 124 static struct kproc_desc sched_kp = { 125 "schedcpu", 126 schedcpu_thread, 127 NULL 128 }; 129 SYSINIT(schedcpu, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, kproc_start, 130 &sched_kp); 131 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL); 132 133 /* 134 * Global run queue. 135 */ 136 static struct runq runq; 137 138 #ifdef SMP 139 /* 140 * Per-CPU run queues 141 */ 142 static struct runq runq_pcpu[MAXCPU]; 143 #endif 144 145 static void 146 setup_runqs(void) 147 { 148 #ifdef SMP 149 int i; 150 151 for (i = 0; i < MAXCPU; ++i) 152 runq_init(&runq_pcpu[i]); 153 #endif 154 155 runq_init(&runq); 156 } 157 158 static int 159 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS) 160 { 161 int error, new_val; 162 163 new_val = sched_quantum * tick; 164 error = sysctl_handle_int(oidp, &new_val, 0, req); 165 if (error != 0 || req->newptr == NULL) 166 return (error); 167 if (new_val < tick) 168 return (EINVAL); 169 sched_quantum = new_val / tick; 170 hogticks = 2 * sched_quantum; 171 return (0); 172 } 173 174 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RD, 0, "Scheduler"); 175 176 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "4BSD", 0, 177 "Scheduler name"); 178 179 SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW, 180 0, sizeof sched_quantum, sysctl_kern_quantum, "I", 181 "Roundrobin scheduling quantum in microseconds"); 182 183 #ifdef SMP 184 /* Enable forwarding of wakeups to all other cpus */ 185 SYSCTL_NODE(_kern_sched, OID_AUTO, ipiwakeup, CTLFLAG_RD, NULL, "Kernel SMP"); 186 187 static int runq_fuzz = 1; 188 SYSCTL_INT(_kern_sched, OID_AUTO, runq_fuzz, CTLFLAG_RW, &runq_fuzz, 0, ""); 189 190 static int forward_wakeup_enabled = 1; 191 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, enabled, CTLFLAG_RW, 192 &forward_wakeup_enabled, 0, 193 "Forwarding of wakeup to idle CPUs"); 194 195 static int forward_wakeups_requested = 0; 196 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, requested, CTLFLAG_RD, 197 &forward_wakeups_requested, 0, 198 "Requests for Forwarding of wakeup to idle CPUs"); 199 200 static int forward_wakeups_delivered = 0; 201 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, delivered, CTLFLAG_RD, 202 &forward_wakeups_delivered, 0, 203 "Completed Forwarding of wakeup to idle CPUs"); 204 205 static int forward_wakeup_use_mask = 1; 206 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, usemask, CTLFLAG_RW, 207 &forward_wakeup_use_mask, 0, 208 "Use the mask of idle cpus"); 209 210 static int forward_wakeup_use_loop = 0; 211 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, useloop, CTLFLAG_RW, 212 &forward_wakeup_use_loop, 0, 213 "Use a loop to find idle cpus"); 214 215 static int forward_wakeup_use_single = 0; 216 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, onecpu, CTLFLAG_RW, 217 &forward_wakeup_use_single, 0, 218 "Only signal one idle cpu"); 219 220 static int forward_wakeup_use_htt = 0; 221 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, htt2, CTLFLAG_RW, 222 &forward_wakeup_use_htt, 0, 223 "account for htt"); 224 225 #endif 226 #if 0 227 static int sched_followon = 0; 228 SYSCTL_INT(_kern_sched, OID_AUTO, followon, CTLFLAG_RW, 229 &sched_followon, 0, 230 "allow threads to share a quantum"); 231 #endif 232 233 static __inline void 234 sched_load_add(void) 235 { 236 sched_tdcnt++; 237 CTR1(KTR_SCHED, "global load: %d", sched_tdcnt); 238 } 239 240 static __inline void 241 sched_load_rem(void) 242 { 243 sched_tdcnt--; 244 CTR1(KTR_SCHED, "global load: %d", sched_tdcnt); 245 } 246 /* 247 * Arrange to reschedule if necessary, taking the priorities and 248 * schedulers into account. 249 */ 250 static void 251 maybe_resched(struct thread *td) 252 { 253 254 THREAD_LOCK_ASSERT(td, MA_OWNED); 255 if (td->td_priority < curthread->td_priority) 256 curthread->td_flags |= TDF_NEEDRESCHED; 257 } 258 259 /* 260 * This function is called when a thread is about to be put on run queue 261 * because it has been made runnable or its priority has been adjusted. It 262 * determines if the new thread should be immediately preempted to. If so, 263 * it switches to it and eventually returns true. If not, it returns false 264 * so that the caller may place the thread on an appropriate run queue. 265 */ 266 int 267 maybe_preempt(struct thread *td) 268 { 269 #ifdef PREEMPTION 270 struct thread *ctd; 271 int cpri, pri; 272 #endif 273 274 #ifdef PREEMPTION 275 /* 276 * The new thread should not preempt the current thread if any of the 277 * following conditions are true: 278 * 279 * - The kernel is in the throes of crashing (panicstr). 280 * - The current thread has a higher (numerically lower) or 281 * equivalent priority. Note that this prevents curthread from 282 * trying to preempt to itself. 283 * - It is too early in the boot for context switches (cold is set). 284 * - The current thread has an inhibitor set or is in the process of 285 * exiting. In this case, the current thread is about to switch 286 * out anyways, so there's no point in preempting. If we did, 287 * the current thread would not be properly resumed as well, so 288 * just avoid that whole landmine. 289 * - If the new thread's priority is not a realtime priority and 290 * the current thread's priority is not an idle priority and 291 * FULL_PREEMPTION is disabled. 292 * 293 * If all of these conditions are false, but the current thread is in 294 * a nested critical section, then we have to defer the preemption 295 * until we exit the critical section. Otherwise, switch immediately 296 * to the new thread. 297 */ 298 ctd = curthread; 299 THREAD_LOCK_ASSERT(td, MA_OWNED); 300 KASSERT((td->td_inhibitors == 0), 301 ("maybe_preempt: trying to run inhibited thread")); 302 pri = td->td_priority; 303 cpri = ctd->td_priority; 304 if (panicstr != NULL || pri >= cpri || cold /* || dumping */ || 305 TD_IS_INHIBITED(ctd)) 306 return (0); 307 #ifndef FULL_PREEMPTION 308 if (pri > PRI_MAX_ITHD && cpri < PRI_MIN_IDLE) 309 return (0); 310 #endif 311 312 if (ctd->td_critnest > 1) { 313 CTR1(KTR_PROC, "maybe_preempt: in critical section %d", 314 ctd->td_critnest); 315 ctd->td_owepreempt = 1; 316 return (0); 317 } 318 /* 319 * Thread is runnable but not yet put on system run queue. 320 */ 321 MPASS(ctd->td_lock == td->td_lock); 322 MPASS(TD_ON_RUNQ(td)); 323 TD_SET_RUNNING(td); 324 CTR3(KTR_PROC, "preempting to thread %p (pid %d, %s)\n", td, 325 td->td_proc->p_pid, td->td_name); 326 mi_switch(SW_INVOL | SW_PREEMPT | SWT_PREEMPT, td); 327 /* 328 * td's lock pointer may have changed. We have to return with it 329 * locked. 330 */ 331 spinlock_enter(); 332 thread_unlock(ctd); 333 thread_lock(td); 334 spinlock_exit(); 335 return (1); 336 #else 337 return (0); 338 #endif 339 } 340 341 /* 342 * Constants for digital decay and forget: 343 * 90% of (td_estcpu) usage in 5 * loadav time 344 * 95% of (ts_pctcpu) usage in 60 seconds (load insensitive) 345 * Note that, as ps(1) mentions, this can let percentages 346 * total over 100% (I've seen 137.9% for 3 processes). 347 * 348 * Note that schedclock() updates td_estcpu and p_cpticks asynchronously. 349 * 350 * We wish to decay away 90% of td_estcpu in (5 * loadavg) seconds. 351 * That is, the system wants to compute a value of decay such 352 * that the following for loop: 353 * for (i = 0; i < (5 * loadavg); i++) 354 * td_estcpu *= decay; 355 * will compute 356 * td_estcpu *= 0.1; 357 * for all values of loadavg: 358 * 359 * Mathematically this loop can be expressed by saying: 360 * decay ** (5 * loadavg) ~= .1 361 * 362 * The system computes decay as: 363 * decay = (2 * loadavg) / (2 * loadavg + 1) 364 * 365 * We wish to prove that the system's computation of decay 366 * will always fulfill the equation: 367 * decay ** (5 * loadavg) ~= .1 368 * 369 * If we compute b as: 370 * b = 2 * loadavg 371 * then 372 * decay = b / (b + 1) 373 * 374 * We now need to prove two things: 375 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1) 376 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg) 377 * 378 * Facts: 379 * For x close to zero, exp(x) =~ 1 + x, since 380 * exp(x) = 0! + x**1/1! + x**2/2! + ... . 381 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b. 382 * For x close to zero, ln(1+x) =~ x, since 383 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1 384 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1). 385 * ln(.1) =~ -2.30 386 * 387 * Proof of (1): 388 * Solve (factor)**(power) =~ .1 given power (5*loadav): 389 * solving for factor, 390 * ln(factor) =~ (-2.30/5*loadav), or 391 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) = 392 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED 393 * 394 * Proof of (2): 395 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)): 396 * solving for power, 397 * power*ln(b/(b+1)) =~ -2.30, or 398 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED 399 * 400 * Actual power values for the implemented algorithm are as follows: 401 * loadav: 1 2 3 4 402 * power: 5.68 10.32 14.94 19.55 403 */ 404 405 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */ 406 #define loadfactor(loadav) (2 * (loadav)) 407 #define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE)) 408 409 /* decay 95% of `ts_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */ 410 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 411 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 412 413 /* 414 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 415 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 416 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 417 * 418 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 419 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 420 * 421 * If you don't want to bother with the faster/more-accurate formula, you 422 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 423 * (more general) method of calculating the %age of CPU used by a process. 424 */ 425 #define CCPU_SHIFT 11 426 427 /* 428 * Recompute process priorities, every hz ticks. 429 * MP-safe, called without the Giant mutex. 430 */ 431 /* ARGSUSED */ 432 static void 433 schedcpu(void) 434 { 435 register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 436 struct thread *td; 437 struct proc *p; 438 struct td_sched *ts; 439 int awake, realstathz; 440 441 realstathz = stathz ? stathz : hz; 442 sx_slock(&allproc_lock); 443 FOREACH_PROC_IN_SYSTEM(p) { 444 PROC_LOCK(p); 445 FOREACH_THREAD_IN_PROC(p, td) { 446 awake = 0; 447 thread_lock(td); 448 ts = td->td_sched; 449 /* 450 * Increment sleep time (if sleeping). We 451 * ignore overflow, as above. 452 */ 453 /* 454 * The td_sched slptimes are not touched in wakeup 455 * because the thread may not HAVE everything in 456 * memory? XXX I think this is out of date. 457 */ 458 if (TD_ON_RUNQ(td)) { 459 awake = 1; 460 td->td_flags &= ~TDF_DIDRUN; 461 } else if (TD_IS_RUNNING(td)) { 462 awake = 1; 463 /* Do not clear TDF_DIDRUN */ 464 } else if (td->td_flags & TDF_DIDRUN) { 465 awake = 1; 466 td->td_flags &= ~TDF_DIDRUN; 467 } 468 469 /* 470 * ts_pctcpu is only for ps and ttyinfo(). 471 */ 472 ts->ts_pctcpu = (ts->ts_pctcpu * ccpu) >> FSHIFT; 473 /* 474 * If the td_sched has been idle the entire second, 475 * stop recalculating its priority until 476 * it wakes up. 477 */ 478 if (ts->ts_cpticks != 0) { 479 #if (FSHIFT >= CCPU_SHIFT) 480 ts->ts_pctcpu += (realstathz == 100) 481 ? ((fixpt_t) ts->ts_cpticks) << 482 (FSHIFT - CCPU_SHIFT) : 483 100 * (((fixpt_t) ts->ts_cpticks) 484 << (FSHIFT - CCPU_SHIFT)) / realstathz; 485 #else 486 ts->ts_pctcpu += ((FSCALE - ccpu) * 487 (ts->ts_cpticks * 488 FSCALE / realstathz)) >> FSHIFT; 489 #endif 490 ts->ts_cpticks = 0; 491 } 492 /* 493 * If there are ANY running threads in this process, 494 * then don't count it as sleeping. 495 XXX this is broken 496 497 */ 498 if (awake) { 499 if (ts->ts_slptime > 1) { 500 /* 501 * In an ideal world, this should not 502 * happen, because whoever woke us 503 * up from the long sleep should have 504 * unwound the slptime and reset our 505 * priority before we run at the stale 506 * priority. Should KASSERT at some 507 * point when all the cases are fixed. 508 */ 509 updatepri(td); 510 } 511 ts->ts_slptime = 0; 512 } else 513 ts->ts_slptime++; 514 if (ts->ts_slptime > 1) { 515 thread_unlock(td); 516 continue; 517 } 518 td->td_estcpu = decay_cpu(loadfac, td->td_estcpu); 519 resetpriority(td); 520 resetpriority_thread(td); 521 thread_unlock(td); 522 } /* end of thread loop */ 523 PROC_UNLOCK(p); 524 } /* end of process loop */ 525 sx_sunlock(&allproc_lock); 526 } 527 528 /* 529 * Main loop for a kthread that executes schedcpu once a second. 530 */ 531 static void 532 schedcpu_thread(void) 533 { 534 535 for (;;) { 536 schedcpu(); 537 pause("-", hz); 538 } 539 } 540 541 /* 542 * Recalculate the priority of a process after it has slept for a while. 543 * For all load averages >= 1 and max td_estcpu of 255, sleeping for at 544 * least six times the loadfactor will decay td_estcpu to zero. 545 */ 546 static void 547 updatepri(struct thread *td) 548 { 549 struct td_sched *ts; 550 fixpt_t loadfac; 551 unsigned int newcpu; 552 553 ts = td->td_sched; 554 loadfac = loadfactor(averunnable.ldavg[0]); 555 if (ts->ts_slptime > 5 * loadfac) 556 td->td_estcpu = 0; 557 else { 558 newcpu = td->td_estcpu; 559 ts->ts_slptime--; /* was incremented in schedcpu() */ 560 while (newcpu && --ts->ts_slptime) 561 newcpu = decay_cpu(loadfac, newcpu); 562 td->td_estcpu = newcpu; 563 } 564 } 565 566 /* 567 * Compute the priority of a process when running in user mode. 568 * Arrange to reschedule if the resulting priority is better 569 * than that of the current process. 570 */ 571 static void 572 resetpriority(struct thread *td) 573 { 574 register unsigned int newpriority; 575 576 if (td->td_pri_class == PRI_TIMESHARE) { 577 newpriority = PUSER + td->td_estcpu / INVERSE_ESTCPU_WEIGHT + 578 NICE_WEIGHT * (td->td_proc->p_nice - PRIO_MIN); 579 newpriority = min(max(newpriority, PRI_MIN_TIMESHARE), 580 PRI_MAX_TIMESHARE); 581 sched_user_prio(td, newpriority); 582 } 583 } 584 585 /* 586 * Update the thread's priority when the associated process's user 587 * priority changes. 588 */ 589 static void 590 resetpriority_thread(struct thread *td) 591 { 592 593 /* Only change threads with a time sharing user priority. */ 594 if (td->td_priority < PRI_MIN_TIMESHARE || 595 td->td_priority > PRI_MAX_TIMESHARE) 596 return; 597 598 /* XXX the whole needresched thing is broken, but not silly. */ 599 maybe_resched(td); 600 601 sched_prio(td, td->td_user_pri); 602 } 603 604 /* ARGSUSED */ 605 static void 606 sched_setup(void *dummy) 607 { 608 setup_runqs(); 609 610 if (sched_quantum == 0) 611 sched_quantum = SCHED_QUANTUM; 612 hogticks = 2 * sched_quantum; 613 614 /* Account for thread0. */ 615 sched_load_add(); 616 } 617 618 /* External interfaces start here */ 619 /* 620 * Very early in the boot some setup of scheduler-specific 621 * parts of proc0 and of some scheduler resources needs to be done. 622 * Called from: 623 * proc0_init() 624 */ 625 void 626 schedinit(void) 627 { 628 /* 629 * Set up the scheduler specific parts of proc0. 630 */ 631 proc0.p_sched = NULL; /* XXX */ 632 thread0.td_sched = &td_sched0; 633 thread0.td_lock = &sched_lock; 634 mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN | MTX_RECURSE); 635 } 636 637 int 638 sched_runnable(void) 639 { 640 #ifdef SMP 641 return runq_check(&runq) + runq_check(&runq_pcpu[PCPU_GET(cpuid)]); 642 #else 643 return runq_check(&runq); 644 #endif 645 } 646 647 int 648 sched_rr_interval(void) 649 { 650 if (sched_quantum == 0) 651 sched_quantum = SCHED_QUANTUM; 652 return (sched_quantum); 653 } 654 655 /* 656 * We adjust the priority of the current process. The priority of 657 * a process gets worse as it accumulates CPU time. The cpu usage 658 * estimator (td_estcpu) is increased here. resetpriority() will 659 * compute a different priority each time td_estcpu increases by 660 * INVERSE_ESTCPU_WEIGHT 661 * (until MAXPRI is reached). The cpu usage estimator ramps up 662 * quite quickly when the process is running (linearly), and decays 663 * away exponentially, at a rate which is proportionally slower when 664 * the system is busy. The basic principle is that the system will 665 * 90% forget that the process used a lot of CPU time in 5 * loadav 666 * seconds. This causes the system to favor processes which haven't 667 * run much recently, and to round-robin among other processes. 668 */ 669 void 670 sched_clock(struct thread *td) 671 { 672 struct td_sched *ts; 673 674 THREAD_LOCK_ASSERT(td, MA_OWNED); 675 ts = td->td_sched; 676 677 ts->ts_cpticks++; 678 td->td_estcpu = ESTCPULIM(td->td_estcpu + 1); 679 if ((td->td_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) { 680 resetpriority(td); 681 resetpriority_thread(td); 682 } 683 684 /* 685 * Force a context switch if the current thread has used up a full 686 * quantum (default quantum is 100ms). 687 */ 688 if (!TD_IS_IDLETHREAD(td) && 689 ticks - PCPU_GET(switchticks) >= sched_quantum) 690 td->td_flags |= TDF_NEEDRESCHED; 691 } 692 693 /* 694 * charge childs scheduling cpu usage to parent. 695 */ 696 void 697 sched_exit(struct proc *p, struct thread *td) 698 { 699 700 CTR3(KTR_SCHED, "sched_exit: %p(%s) prio %d", 701 td, td->td_name, td->td_priority); 702 PROC_LOCK_ASSERT(p, MA_OWNED); 703 sched_exit_thread(FIRST_THREAD_IN_PROC(p), td); 704 } 705 706 void 707 sched_exit_thread(struct thread *td, struct thread *child) 708 { 709 710 CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d", 711 child, child->td_name, child->td_priority); 712 thread_lock(td); 713 td->td_estcpu = ESTCPULIM(td->td_estcpu + child->td_estcpu); 714 thread_unlock(td); 715 mtx_lock_spin(&sched_lock); 716 if ((child->td_proc->p_flag & P_NOLOAD) == 0) 717 sched_load_rem(); 718 mtx_unlock_spin(&sched_lock); 719 } 720 721 void 722 sched_fork(struct thread *td, struct thread *childtd) 723 { 724 sched_fork_thread(td, childtd); 725 } 726 727 void 728 sched_fork_thread(struct thread *td, struct thread *childtd) 729 { 730 struct td_sched *ts; 731 732 childtd->td_estcpu = td->td_estcpu; 733 childtd->td_lock = &sched_lock; 734 childtd->td_cpuset = cpuset_ref(td->td_cpuset); 735 ts = childtd->td_sched; 736 bzero(ts, sizeof(*ts)); 737 } 738 739 void 740 sched_nice(struct proc *p, int nice) 741 { 742 struct thread *td; 743 744 PROC_LOCK_ASSERT(p, MA_OWNED); 745 p->p_nice = nice; 746 FOREACH_THREAD_IN_PROC(p, td) { 747 thread_lock(td); 748 resetpriority(td); 749 resetpriority_thread(td); 750 thread_unlock(td); 751 } 752 } 753 754 void 755 sched_class(struct thread *td, int class) 756 { 757 THREAD_LOCK_ASSERT(td, MA_OWNED); 758 td->td_pri_class = class; 759 } 760 761 /* 762 * Adjust the priority of a thread. 763 */ 764 static void 765 sched_priority(struct thread *td, u_char prio) 766 { 767 CTR6(KTR_SCHED, "sched_prio: %p(%s) prio %d newprio %d by %p(%s)", 768 td, td->td_name, td->td_priority, prio, curthread, 769 curthread->td_name); 770 771 THREAD_LOCK_ASSERT(td, MA_OWNED); 772 if (td->td_priority == prio) 773 return; 774 td->td_priority = prio; 775 if (TD_ON_RUNQ(td) && td->td_rqindex != (prio / RQ_PPQ)) { 776 sched_rem(td); 777 sched_add(td, SRQ_BORING); 778 } 779 } 780 781 /* 782 * Update a thread's priority when it is lent another thread's 783 * priority. 784 */ 785 void 786 sched_lend_prio(struct thread *td, u_char prio) 787 { 788 789 td->td_flags |= TDF_BORROWING; 790 sched_priority(td, prio); 791 } 792 793 /* 794 * Restore a thread's priority when priority propagation is 795 * over. The prio argument is the minimum priority the thread 796 * needs to have to satisfy other possible priority lending 797 * requests. If the thread's regulary priority is less 798 * important than prio the thread will keep a priority boost 799 * of prio. 800 */ 801 void 802 sched_unlend_prio(struct thread *td, u_char prio) 803 { 804 u_char base_pri; 805 806 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 807 td->td_base_pri <= PRI_MAX_TIMESHARE) 808 base_pri = td->td_user_pri; 809 else 810 base_pri = td->td_base_pri; 811 if (prio >= base_pri) { 812 td->td_flags &= ~TDF_BORROWING; 813 sched_prio(td, base_pri); 814 } else 815 sched_lend_prio(td, prio); 816 } 817 818 void 819 sched_prio(struct thread *td, u_char prio) 820 { 821 u_char oldprio; 822 823 /* First, update the base priority. */ 824 td->td_base_pri = prio; 825 826 /* 827 * If the thread is borrowing another thread's priority, don't ever 828 * lower the priority. 829 */ 830 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 831 return; 832 833 /* Change the real priority. */ 834 oldprio = td->td_priority; 835 sched_priority(td, prio); 836 837 /* 838 * If the thread is on a turnstile, then let the turnstile update 839 * its state. 840 */ 841 if (TD_ON_LOCK(td) && oldprio != prio) 842 turnstile_adjust(td, oldprio); 843 } 844 845 void 846 sched_user_prio(struct thread *td, u_char prio) 847 { 848 u_char oldprio; 849 850 THREAD_LOCK_ASSERT(td, MA_OWNED); 851 td->td_base_user_pri = prio; 852 if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio) 853 return; 854 oldprio = td->td_user_pri; 855 td->td_user_pri = prio; 856 } 857 858 void 859 sched_lend_user_prio(struct thread *td, u_char prio) 860 { 861 u_char oldprio; 862 863 THREAD_LOCK_ASSERT(td, MA_OWNED); 864 td->td_flags |= TDF_UBORROWING; 865 oldprio = td->td_user_pri; 866 td->td_user_pri = prio; 867 } 868 869 void 870 sched_unlend_user_prio(struct thread *td, u_char prio) 871 { 872 u_char base_pri; 873 874 THREAD_LOCK_ASSERT(td, MA_OWNED); 875 base_pri = td->td_base_user_pri; 876 if (prio >= base_pri) { 877 td->td_flags &= ~TDF_UBORROWING; 878 sched_user_prio(td, base_pri); 879 } else { 880 sched_lend_user_prio(td, prio); 881 } 882 } 883 884 void 885 sched_sleep(struct thread *td, int pri) 886 { 887 888 THREAD_LOCK_ASSERT(td, MA_OWNED); 889 td->td_slptick = ticks; 890 td->td_sched->ts_slptime = 0; 891 if (pri) 892 sched_prio(td, pri); 893 if (TD_IS_SUSPENDED(td) || pri <= PSOCK) 894 td->td_flags |= TDF_CANSWAP; 895 } 896 897 void 898 sched_switch(struct thread *td, struct thread *newtd, int flags) 899 { 900 struct td_sched *ts; 901 struct proc *p; 902 903 ts = td->td_sched; 904 p = td->td_proc; 905 906 THREAD_LOCK_ASSERT(td, MA_OWNED); 907 /* 908 * Switch to the sched lock to fix things up and pick 909 * a new thread. 910 */ 911 if (td->td_lock != &sched_lock) { 912 mtx_lock_spin(&sched_lock); 913 thread_unlock(td); 914 } 915 916 if ((p->p_flag & P_NOLOAD) == 0) 917 sched_load_rem(); 918 919 if (newtd) 920 newtd->td_flags |= (td->td_flags & TDF_NEEDRESCHED); 921 922 td->td_lastcpu = td->td_oncpu; 923 td->td_flags &= ~TDF_NEEDRESCHED; 924 td->td_owepreempt = 0; 925 td->td_oncpu = NOCPU; 926 /* 927 * At the last moment, if this thread is still marked RUNNING, 928 * then put it back on the run queue as it has not been suspended 929 * or stopped or any thing else similar. We never put the idle 930 * threads on the run queue, however. 931 */ 932 if (td->td_flags & TDF_IDLETD) { 933 TD_SET_CAN_RUN(td); 934 #ifdef SMP 935 idle_cpus_mask &= ~PCPU_GET(cpumask); 936 #endif 937 } else { 938 if (TD_IS_RUNNING(td)) { 939 /* Put us back on the run queue. */ 940 sched_add(td, (flags & SW_PREEMPT) ? 941 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 942 SRQ_OURSELF|SRQ_YIELDING); 943 } 944 } 945 if (newtd) { 946 /* 947 * The thread we are about to run needs to be counted 948 * as if it had been added to the run queue and selected. 949 * It came from: 950 * * A preemption 951 * * An upcall 952 * * A followon 953 */ 954 KASSERT((newtd->td_inhibitors == 0), 955 ("trying to run inhibited thread")); 956 newtd->td_flags |= TDF_DIDRUN; 957 TD_SET_RUNNING(newtd); 958 if ((newtd->td_proc->p_flag & P_NOLOAD) == 0) 959 sched_load_add(); 960 } else { 961 newtd = choosethread(); 962 } 963 MPASS(newtd->td_lock == &sched_lock); 964 965 if (td != newtd) { 966 #ifdef HWPMC_HOOKS 967 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 968 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 969 #endif 970 /* I feel sleepy */ 971 lock_profile_release_lock(&sched_lock.lock_object); 972 #ifdef KDTRACE_HOOKS 973 /* 974 * If DTrace has set the active vtime enum to anything 975 * other than INACTIVE (0), then it should have set the 976 * function to call. 977 */ 978 if (dtrace_vtime_active) 979 (*dtrace_vtime_switch_func)(newtd); 980 #endif 981 982 cpu_switch(td, newtd, td->td_lock); 983 lock_profile_obtain_lock_success(&sched_lock.lock_object, 984 0, 0, __FILE__, __LINE__); 985 /* 986 * Where am I? What year is it? 987 * We are in the same thread that went to sleep above, 988 * but any amount of time may have passed. All out context 989 * will still be available as will local variables. 990 * PCPU values however may have changed as we may have 991 * changed CPU so don't trust cached values of them. 992 * New threads will go to fork_exit() instead of here 993 * so if you change things here you may need to change 994 * things there too. 995 * If the thread above was exiting it will never wake 996 * up again here, so either it has saved everything it 997 * needed to, or the thread_wait() or wait() will 998 * need to reap it. 999 */ 1000 #ifdef HWPMC_HOOKS 1001 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1002 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1003 #endif 1004 } 1005 1006 #ifdef SMP 1007 if (td->td_flags & TDF_IDLETD) 1008 idle_cpus_mask |= PCPU_GET(cpumask); 1009 #endif 1010 sched_lock.mtx_lock = (uintptr_t)td; 1011 td->td_oncpu = PCPU_GET(cpuid); 1012 MPASS(td->td_lock == &sched_lock); 1013 } 1014 1015 void 1016 sched_wakeup(struct thread *td) 1017 { 1018 struct td_sched *ts; 1019 1020 THREAD_LOCK_ASSERT(td, MA_OWNED); 1021 ts = td->td_sched; 1022 td->td_flags &= ~TDF_CANSWAP; 1023 if (ts->ts_slptime > 1) { 1024 updatepri(td); 1025 resetpriority(td); 1026 } 1027 td->td_slptick = ticks; 1028 ts->ts_slptime = 0; 1029 sched_add(td, SRQ_BORING); 1030 } 1031 1032 #ifdef SMP 1033 /* enable HTT_2 if you have a 2-way HTT cpu.*/ 1034 static int 1035 forward_wakeup(int cpunum) 1036 { 1037 cpumask_t map, me, dontuse; 1038 cpumask_t map2; 1039 struct pcpu *pc; 1040 cpumask_t id, map3; 1041 1042 mtx_assert(&sched_lock, MA_OWNED); 1043 1044 CTR0(KTR_RUNQ, "forward_wakeup()"); 1045 1046 if ((!forward_wakeup_enabled) || 1047 (forward_wakeup_use_mask == 0 && forward_wakeup_use_loop == 0)) 1048 return (0); 1049 if (!smp_started || cold || panicstr) 1050 return (0); 1051 1052 forward_wakeups_requested++; 1053 1054 /* 1055 * check the idle mask we received against what we calculated before 1056 * in the old version. 1057 */ 1058 me = PCPU_GET(cpumask); 1059 /* 1060 * don't bother if we should be doing it ourself.. 1061 */ 1062 if ((me & idle_cpus_mask) && (cpunum == NOCPU || me == (1 << cpunum))) 1063 return (0); 1064 1065 dontuse = me | stopped_cpus | hlt_cpus_mask; 1066 map3 = 0; 1067 if (forward_wakeup_use_loop) { 1068 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) { 1069 id = pc->pc_cpumask; 1070 if ( (id & dontuse) == 0 && 1071 pc->pc_curthread == pc->pc_idlethread) { 1072 map3 |= id; 1073 } 1074 } 1075 } 1076 1077 if (forward_wakeup_use_mask) { 1078 map = 0; 1079 map = idle_cpus_mask & ~dontuse; 1080 1081 /* If they are both on, compare and use loop if different */ 1082 if (forward_wakeup_use_loop) { 1083 if (map != map3) { 1084 printf("map (%02X) != map3 (%02X)\n", 1085 map, map3); 1086 map = map3; 1087 } 1088 } 1089 } else { 1090 map = map3; 1091 } 1092 /* If we only allow a specific CPU, then mask off all the others */ 1093 if (cpunum != NOCPU) { 1094 KASSERT((cpunum <= mp_maxcpus),("forward_wakeup: bad cpunum.")); 1095 map &= (1 << cpunum); 1096 } else { 1097 /* Try choose an idle die. */ 1098 if (forward_wakeup_use_htt) { 1099 map2 = (map & (map >> 1)) & 0x5555; 1100 if (map2) { 1101 map = map2; 1102 } 1103 } 1104 1105 /* set only one bit */ 1106 if (forward_wakeup_use_single) { 1107 map = map & ((~map) + 1); 1108 } 1109 } 1110 if (map) { 1111 forward_wakeups_delivered++; 1112 ipi_selected(map, IPI_AST); 1113 return (1); 1114 } 1115 if (cpunum == NOCPU) 1116 printf("forward_wakeup: Idle processor not found\n"); 1117 return (0); 1118 } 1119 #endif 1120 1121 #ifdef SMP 1122 static void kick_other_cpu(int pri,int cpuid); 1123 1124 static void 1125 kick_other_cpu(int pri,int cpuid) 1126 { 1127 struct pcpu * pcpu = pcpu_find(cpuid); 1128 int cpri = pcpu->pc_curthread->td_priority; 1129 1130 if (idle_cpus_mask & pcpu->pc_cpumask) { 1131 forward_wakeups_delivered++; 1132 ipi_selected(pcpu->pc_cpumask, IPI_AST); 1133 return; 1134 } 1135 1136 if (pri >= cpri) 1137 return; 1138 1139 #if defined(IPI_PREEMPTION) && defined(PREEMPTION) 1140 #if !defined(FULL_PREEMPTION) 1141 if (pri <= PRI_MAX_ITHD) 1142 #endif /* ! FULL_PREEMPTION */ 1143 { 1144 ipi_selected(pcpu->pc_cpumask, IPI_PREEMPT); 1145 return; 1146 } 1147 #endif /* defined(IPI_PREEMPTION) && defined(PREEMPTION) */ 1148 1149 pcpu->pc_curthread->td_flags |= TDF_NEEDRESCHED; 1150 ipi_selected( pcpu->pc_cpumask , IPI_AST); 1151 return; 1152 } 1153 #endif /* SMP */ 1154 1155 void 1156 sched_add(struct thread *td, int flags) 1157 #ifdef SMP 1158 { 1159 struct td_sched *ts; 1160 int forwarded = 0; 1161 int cpu; 1162 int single_cpu = 0; 1163 1164 ts = td->td_sched; 1165 THREAD_LOCK_ASSERT(td, MA_OWNED); 1166 KASSERT((td->td_inhibitors == 0), 1167 ("sched_add: trying to run inhibited thread")); 1168 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 1169 ("sched_add: bad thread state")); 1170 KASSERT(td->td_flags & TDF_INMEM, 1171 ("sched_add: thread swapped out")); 1172 CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)", 1173 td, td->td_name, td->td_priority, curthread, 1174 curthread->td_name); 1175 /* 1176 * Now that the thread is moving to the run-queue, set the lock 1177 * to the scheduler's lock. 1178 */ 1179 if (td->td_lock != &sched_lock) { 1180 mtx_lock_spin(&sched_lock); 1181 thread_lock_set(td, &sched_lock); 1182 } 1183 TD_SET_RUNQ(td); 1184 1185 if (td->td_pinned != 0) { 1186 cpu = td->td_lastcpu; 1187 ts->ts_runq = &runq_pcpu[cpu]; 1188 single_cpu = 1; 1189 CTR3(KTR_RUNQ, 1190 "sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td, cpu); 1191 } else if ((td)->td_flags & TDF_BOUND) { 1192 /* Find CPU from bound runq */ 1193 KASSERT(SKE_RUNQ_PCPU(ts),("sched_add: bound td_sched not on cpu runq")); 1194 cpu = ts->ts_runq - &runq_pcpu[0]; 1195 single_cpu = 1; 1196 CTR3(KTR_RUNQ, 1197 "sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td, cpu); 1198 } else { 1199 CTR2(KTR_RUNQ, 1200 "sched_add: adding td_sched:%p (td:%p) to gbl runq", ts, td); 1201 cpu = NOCPU; 1202 ts->ts_runq = &runq; 1203 } 1204 1205 if (single_cpu && (cpu != PCPU_GET(cpuid))) { 1206 kick_other_cpu(td->td_priority,cpu); 1207 } else { 1208 1209 if (!single_cpu) { 1210 cpumask_t me = PCPU_GET(cpumask); 1211 int idle = idle_cpus_mask & me; 1212 1213 if (!idle && ((flags & SRQ_INTR) == 0) && 1214 (idle_cpus_mask & ~(hlt_cpus_mask | me))) 1215 forwarded = forward_wakeup(cpu); 1216 } 1217 1218 if (!forwarded) { 1219 if ((flags & SRQ_YIELDING) == 0 && maybe_preempt(td)) 1220 return; 1221 else 1222 maybe_resched(td); 1223 } 1224 } 1225 1226 if ((td->td_proc->p_flag & P_NOLOAD) == 0) 1227 sched_load_add(); 1228 runq_add(ts->ts_runq, td, flags); 1229 } 1230 #else /* SMP */ 1231 { 1232 struct td_sched *ts; 1233 ts = td->td_sched; 1234 THREAD_LOCK_ASSERT(td, MA_OWNED); 1235 KASSERT((td->td_inhibitors == 0), 1236 ("sched_add: trying to run inhibited thread")); 1237 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 1238 ("sched_add: bad thread state")); 1239 KASSERT(td->td_flags & TDF_INMEM, 1240 ("sched_add: thread swapped out")); 1241 CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)", 1242 td, td->td_name, td->td_priority, curthread, 1243 curthread->td_name); 1244 /* 1245 * Now that the thread is moving to the run-queue, set the lock 1246 * to the scheduler's lock. 1247 */ 1248 if (td->td_lock != &sched_lock) { 1249 mtx_lock_spin(&sched_lock); 1250 thread_lock_set(td, &sched_lock); 1251 } 1252 TD_SET_RUNQ(td); 1253 CTR2(KTR_RUNQ, "sched_add: adding td_sched:%p (td:%p) to runq", ts, td); 1254 ts->ts_runq = &runq; 1255 1256 /* 1257 * If we are yielding (on the way out anyhow) 1258 * or the thread being saved is US, 1259 * then don't try be smart about preemption 1260 * or kicking off another CPU 1261 * as it won't help and may hinder. 1262 * In the YIEDLING case, we are about to run whoever is 1263 * being put in the queue anyhow, and in the 1264 * OURSELF case, we are puting ourself on the run queue 1265 * which also only happens when we are about to yield. 1266 */ 1267 if((flags & SRQ_YIELDING) == 0) { 1268 if (maybe_preempt(td)) 1269 return; 1270 } 1271 if ((td->td_proc->p_flag & P_NOLOAD) == 0) 1272 sched_load_add(); 1273 runq_add(ts->ts_runq, td, flags); 1274 maybe_resched(td); 1275 } 1276 #endif /* SMP */ 1277 1278 void 1279 sched_rem(struct thread *td) 1280 { 1281 struct td_sched *ts; 1282 1283 ts = td->td_sched; 1284 KASSERT(td->td_flags & TDF_INMEM, 1285 ("sched_rem: thread swapped out")); 1286 KASSERT(TD_ON_RUNQ(td), 1287 ("sched_rem: thread not on run queue")); 1288 mtx_assert(&sched_lock, MA_OWNED); 1289 CTR5(KTR_SCHED, "sched_rem: %p(%s) prio %d by %p(%s)", 1290 td, td->td_name, td->td_priority, curthread, 1291 curthread->td_name); 1292 1293 if ((td->td_proc->p_flag & P_NOLOAD) == 0) 1294 sched_load_rem(); 1295 runq_remove(ts->ts_runq, td); 1296 TD_SET_CAN_RUN(td); 1297 } 1298 1299 /* 1300 * Select threads to run. 1301 * Notice that the running threads still consume a slot. 1302 */ 1303 struct thread * 1304 sched_choose(void) 1305 { 1306 struct thread *td; 1307 struct runq *rq; 1308 1309 mtx_assert(&sched_lock, MA_OWNED); 1310 #ifdef SMP 1311 struct thread *tdcpu; 1312 1313 rq = &runq; 1314 td = runq_choose_fuzz(&runq, runq_fuzz); 1315 tdcpu = runq_choose(&runq_pcpu[PCPU_GET(cpuid)]); 1316 1317 if (td == NULL || 1318 (tdcpu != NULL && 1319 tdcpu->td_priority < td->td_priority)) { 1320 CTR2(KTR_RUNQ, "choosing td %p from pcpu runq %d", tdcpu, 1321 PCPU_GET(cpuid)); 1322 td = tdcpu; 1323 rq = &runq_pcpu[PCPU_GET(cpuid)]; 1324 } else { 1325 CTR1(KTR_RUNQ, "choosing td_sched %p from main runq", td); 1326 } 1327 1328 #else 1329 rq = &runq; 1330 td = runq_choose(&runq); 1331 #endif 1332 1333 if (td) { 1334 runq_remove(rq, td); 1335 td->td_flags |= TDF_DIDRUN; 1336 1337 KASSERT(td->td_flags & TDF_INMEM, 1338 ("sched_choose: thread swapped out")); 1339 return (td); 1340 } 1341 return (PCPU_GET(idlethread)); 1342 } 1343 1344 void 1345 sched_preempt(struct thread *td) 1346 { 1347 thread_lock(td); 1348 if (td->td_critnest > 1) 1349 td->td_owepreempt = 1; 1350 else 1351 mi_switch(SW_INVOL | SW_PREEMPT | SWT_PREEMPT, NULL); 1352 thread_unlock(td); 1353 } 1354 1355 void 1356 sched_userret(struct thread *td) 1357 { 1358 /* 1359 * XXX we cheat slightly on the locking here to avoid locking in 1360 * the usual case. Setting td_priority here is essentially an 1361 * incomplete workaround for not setting it properly elsewhere. 1362 * Now that some interrupt handlers are threads, not setting it 1363 * properly elsewhere can clobber it in the window between setting 1364 * it here and returning to user mode, so don't waste time setting 1365 * it perfectly here. 1366 */ 1367 KASSERT((td->td_flags & TDF_BORROWING) == 0, 1368 ("thread with borrowed priority returning to userland")); 1369 if (td->td_priority != td->td_user_pri) { 1370 thread_lock(td); 1371 td->td_priority = td->td_user_pri; 1372 td->td_base_pri = td->td_user_pri; 1373 thread_unlock(td); 1374 } 1375 } 1376 1377 void 1378 sched_bind(struct thread *td, int cpu) 1379 { 1380 struct td_sched *ts; 1381 1382 THREAD_LOCK_ASSERT(td, MA_OWNED); 1383 KASSERT(TD_IS_RUNNING(td), 1384 ("sched_bind: cannot bind non-running thread")); 1385 1386 ts = td->td_sched; 1387 1388 td->td_flags |= TDF_BOUND; 1389 #ifdef SMP 1390 ts->ts_runq = &runq_pcpu[cpu]; 1391 if (PCPU_GET(cpuid) == cpu) 1392 return; 1393 1394 mi_switch(SW_VOL, NULL); 1395 #endif 1396 } 1397 1398 void 1399 sched_unbind(struct thread* td) 1400 { 1401 THREAD_LOCK_ASSERT(td, MA_OWNED); 1402 td->td_flags &= ~TDF_BOUND; 1403 } 1404 1405 int 1406 sched_is_bound(struct thread *td) 1407 { 1408 THREAD_LOCK_ASSERT(td, MA_OWNED); 1409 return (td->td_flags & TDF_BOUND); 1410 } 1411 1412 void 1413 sched_relinquish(struct thread *td) 1414 { 1415 thread_lock(td); 1416 mi_switch(SW_VOL | SWT_RELINQUISH, NULL); 1417 thread_unlock(td); 1418 } 1419 1420 int 1421 sched_load(void) 1422 { 1423 return (sched_tdcnt); 1424 } 1425 1426 int 1427 sched_sizeof_proc(void) 1428 { 1429 return (sizeof(struct proc)); 1430 } 1431 1432 int 1433 sched_sizeof_thread(void) 1434 { 1435 return (sizeof(struct thread) + sizeof(struct td_sched)); 1436 } 1437 1438 fixpt_t 1439 sched_pctcpu(struct thread *td) 1440 { 1441 struct td_sched *ts; 1442 1443 ts = td->td_sched; 1444 return (ts->ts_pctcpu); 1445 } 1446 1447 void 1448 sched_tick(void) 1449 { 1450 } 1451 1452 /* 1453 * The actual idle process. 1454 */ 1455 void 1456 sched_idletd(void *dummy) 1457 { 1458 1459 for (;;) { 1460 mtx_assert(&Giant, MA_NOTOWNED); 1461 1462 while (sched_runnable() == 0) 1463 cpu_idle(0); 1464 1465 mtx_lock_spin(&sched_lock); 1466 mi_switch(SW_VOL | SWT_IDLE, NULL); 1467 mtx_unlock_spin(&sched_lock); 1468 } 1469 } 1470 1471 /* 1472 * A CPU is entering for the first time or a thread is exiting. 1473 */ 1474 void 1475 sched_throw(struct thread *td) 1476 { 1477 /* 1478 * Correct spinlock nesting. The idle thread context that we are 1479 * borrowing was created so that it would start out with a single 1480 * spin lock (sched_lock) held in fork_trampoline(). Since we've 1481 * explicitly acquired locks in this function, the nesting count 1482 * is now 2 rather than 1. Since we are nested, calling 1483 * spinlock_exit() will simply adjust the counts without allowing 1484 * spin lock using code to interrupt us. 1485 */ 1486 if (td == NULL) { 1487 mtx_lock_spin(&sched_lock); 1488 spinlock_exit(); 1489 } else { 1490 lock_profile_release_lock(&sched_lock.lock_object); 1491 MPASS(td->td_lock == &sched_lock); 1492 } 1493 mtx_assert(&sched_lock, MA_OWNED); 1494 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 1495 PCPU_SET(switchtime, cpu_ticks()); 1496 PCPU_SET(switchticks, ticks); 1497 cpu_throw(td, choosethread()); /* doesn't return */ 1498 } 1499 1500 void 1501 sched_fork_exit(struct thread *td) 1502 { 1503 1504 /* 1505 * Finish setting up thread glue so that it begins execution in a 1506 * non-nested critical section with sched_lock held but not recursed. 1507 */ 1508 td->td_oncpu = PCPU_GET(cpuid); 1509 sched_lock.mtx_lock = (uintptr_t)td; 1510 lock_profile_obtain_lock_success(&sched_lock.lock_object, 1511 0, 0, __FILE__, __LINE__); 1512 THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED); 1513 } 1514 1515 void 1516 sched_affinity(struct thread *td) 1517 { 1518 } 1519