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 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/kernel.h> 43 #include <sys/ktr.h> 44 #include <sys/lock.h> 45 #include <sys/kthread.h> 46 #include <sys/mutex.h> 47 #include <sys/proc.h> 48 #include <sys/resourcevar.h> 49 #include <sys/sched.h> 50 #include <sys/smp.h> 51 #include <sys/sysctl.h> 52 #include <sys/sx.h> 53 #include <sys/turnstile.h> 54 #include <sys/umtx.h> 55 #include <machine/pcb.h> 56 #include <machine/smp.h> 57 58 #ifdef HWPMC_HOOKS 59 #include <sys/pmckern.h> 60 #endif 61 62 /* 63 * INVERSE_ESTCPU_WEIGHT is only suitable for statclock() frequencies in 64 * the range 100-256 Hz (approximately). 65 */ 66 #define ESTCPULIM(e) \ 67 min((e), INVERSE_ESTCPU_WEIGHT * (NICE_WEIGHT * (PRIO_MAX - PRIO_MIN) - \ 68 RQ_PPQ) + INVERSE_ESTCPU_WEIGHT - 1) 69 #ifdef SMP 70 #define INVERSE_ESTCPU_WEIGHT (8 * smp_cpus) 71 #else 72 #define INVERSE_ESTCPU_WEIGHT 8 /* 1 / (priorities per estcpu level). */ 73 #endif 74 #define NICE_WEIGHT 1 /* Priorities per nice level. */ 75 76 /* 77 * The schedulable entity that runs a context. 78 * This is an extension to the thread structure and is tailored to 79 * the requirements of this scheduler 80 */ 81 struct td_sched { 82 TAILQ_ENTRY(td_sched) ts_procq; /* (j/z) Run queue. */ 83 struct thread *ts_thread; /* (*) Active associated thread. */ 84 fixpt_t ts_pctcpu; /* (j) %cpu during p_swtime. */ 85 u_char ts_rqindex; /* (j) Run queue index. */ 86 int ts_cpticks; /* (j) Ticks of cpu time. */ 87 struct runq *ts_runq; /* runq the thread is currently on */ 88 }; 89 90 /* flags kept in td_flags */ 91 #define TDF_DIDRUN TDF_SCHED0 /* thread actually ran. */ 92 #define TDF_EXIT TDF_SCHED1 /* thread is being killed. */ 93 #define TDF_BOUND TDF_SCHED2 94 95 #define ts_flags ts_thread->td_flags 96 #define TSF_DIDRUN TDF_DIDRUN /* thread actually ran. */ 97 #define TSF_EXIT TDF_EXIT /* thread is being killed. */ 98 #define TSF_BOUND TDF_BOUND /* stuck to one CPU */ 99 100 #define SKE_RUNQ_PCPU(ts) \ 101 ((ts)->ts_runq != 0 && (ts)->ts_runq != &runq) 102 103 static struct td_sched td_sched0; 104 105 static int sched_tdcnt; /* Total runnable threads in the system. */ 106 static int sched_quantum; /* Roundrobin scheduling quantum in ticks. */ 107 #define SCHED_QUANTUM (hz / 10) /* Default sched quantum */ 108 109 static struct callout roundrobin_callout; 110 111 static void setup_runqs(void); 112 static void roundrobin(void *arg); 113 static void schedcpu(void); 114 static void schedcpu_thread(void); 115 static void sched_priority(struct thread *td, u_char prio); 116 static void sched_setup(void *dummy); 117 static void maybe_resched(struct thread *td); 118 static void updatepri(struct thread *td); 119 static void resetpriority(struct thread *td); 120 static void resetpriority_thread(struct thread *td); 121 #ifdef SMP 122 static int forward_wakeup(int cpunum); 123 #endif 124 125 static struct kproc_desc sched_kp = { 126 "schedcpu", 127 schedcpu_thread, 128 NULL 129 }; 130 SYSINIT(schedcpu, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, kproc_start, &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 forward_wakeup_enabled = 1; 188 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, enabled, CTLFLAG_RW, 189 &forward_wakeup_enabled, 0, 190 "Forwarding of wakeup to idle CPUs"); 191 192 static int forward_wakeups_requested = 0; 193 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, requested, CTLFLAG_RD, 194 &forward_wakeups_requested, 0, 195 "Requests for Forwarding of wakeup to idle CPUs"); 196 197 static int forward_wakeups_delivered = 0; 198 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, delivered, CTLFLAG_RD, 199 &forward_wakeups_delivered, 0, 200 "Completed Forwarding of wakeup to idle CPUs"); 201 202 static int forward_wakeup_use_mask = 1; 203 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, usemask, CTLFLAG_RW, 204 &forward_wakeup_use_mask, 0, 205 "Use the mask of idle cpus"); 206 207 static int forward_wakeup_use_loop = 0; 208 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, useloop, CTLFLAG_RW, 209 &forward_wakeup_use_loop, 0, 210 "Use a loop to find idle cpus"); 211 212 static int forward_wakeup_use_single = 0; 213 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, onecpu, CTLFLAG_RW, 214 &forward_wakeup_use_single, 0, 215 "Only signal one idle cpu"); 216 217 static int forward_wakeup_use_htt = 0; 218 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, htt2, CTLFLAG_RW, 219 &forward_wakeup_use_htt, 0, 220 "account for htt"); 221 222 #endif 223 #if 0 224 static int sched_followon = 0; 225 SYSCTL_INT(_kern_sched, OID_AUTO, followon, CTLFLAG_RW, 226 &sched_followon, 0, 227 "allow threads to share a quantum"); 228 #endif 229 230 static __inline void 231 sched_load_add(void) 232 { 233 sched_tdcnt++; 234 CTR1(KTR_SCHED, "global load: %d", sched_tdcnt); 235 } 236 237 static __inline void 238 sched_load_rem(void) 239 { 240 sched_tdcnt--; 241 CTR1(KTR_SCHED, "global load: %d", sched_tdcnt); 242 } 243 /* 244 * Arrange to reschedule if necessary, taking the priorities and 245 * schedulers into account. 246 */ 247 static void 248 maybe_resched(struct thread *td) 249 { 250 251 THREAD_LOCK_ASSERT(td, MA_OWNED); 252 if (td->td_priority < curthread->td_priority) 253 curthread->td_flags |= TDF_NEEDRESCHED; 254 } 255 256 /* 257 * Force switch among equal priority processes every 100ms. 258 * We don't actually need to force a context switch of the current process. 259 * The act of firing the event triggers a context switch to softclock() and 260 * then switching back out again which is equivalent to a preemption, thus 261 * no further work is needed on the local CPU. 262 */ 263 /* ARGSUSED */ 264 static void 265 roundrobin(void *arg) 266 { 267 268 #ifdef SMP 269 mtx_lock_spin(&sched_lock); 270 forward_roundrobin(); 271 mtx_unlock_spin(&sched_lock); 272 #endif 273 274 callout_reset(&roundrobin_callout, sched_quantum, roundrobin, NULL); 275 } 276 277 /* 278 * Constants for digital decay and forget: 279 * 90% of (td_estcpu) usage in 5 * loadav time 280 * 95% of (ts_pctcpu) usage in 60 seconds (load insensitive) 281 * Note that, as ps(1) mentions, this can let percentages 282 * total over 100% (I've seen 137.9% for 3 processes). 283 * 284 * Note that schedclock() updates td_estcpu and p_cpticks asynchronously. 285 * 286 * We wish to decay away 90% of td_estcpu in (5 * loadavg) seconds. 287 * That is, the system wants to compute a value of decay such 288 * that the following for loop: 289 * for (i = 0; i < (5 * loadavg); i++) 290 * td_estcpu *= decay; 291 * will compute 292 * td_estcpu *= 0.1; 293 * for all values of loadavg: 294 * 295 * Mathematically this loop can be expressed by saying: 296 * decay ** (5 * loadavg) ~= .1 297 * 298 * The system computes decay as: 299 * decay = (2 * loadavg) / (2 * loadavg + 1) 300 * 301 * We wish to prove that the system's computation of decay 302 * will always fulfill the equation: 303 * decay ** (5 * loadavg) ~= .1 304 * 305 * If we compute b as: 306 * b = 2 * loadavg 307 * then 308 * decay = b / (b + 1) 309 * 310 * We now need to prove two things: 311 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1) 312 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg) 313 * 314 * Facts: 315 * For x close to zero, exp(x) =~ 1 + x, since 316 * exp(x) = 0! + x**1/1! + x**2/2! + ... . 317 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b. 318 * For x close to zero, ln(1+x) =~ x, since 319 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1 320 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1). 321 * ln(.1) =~ -2.30 322 * 323 * Proof of (1): 324 * Solve (factor)**(power) =~ .1 given power (5*loadav): 325 * solving for factor, 326 * ln(factor) =~ (-2.30/5*loadav), or 327 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) = 328 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED 329 * 330 * Proof of (2): 331 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)): 332 * solving for power, 333 * power*ln(b/(b+1)) =~ -2.30, or 334 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED 335 * 336 * Actual power values for the implemented algorithm are as follows: 337 * loadav: 1 2 3 4 338 * power: 5.68 10.32 14.94 19.55 339 */ 340 341 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */ 342 #define loadfactor(loadav) (2 * (loadav)) 343 #define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE)) 344 345 /* decay 95% of `ts_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */ 346 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 347 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 348 349 /* 350 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 351 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 352 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 353 * 354 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 355 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 356 * 357 * If you don't want to bother with the faster/more-accurate formula, you 358 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 359 * (more general) method of calculating the %age of CPU used by a process. 360 */ 361 #define CCPU_SHIFT 11 362 363 /* 364 * Recompute process priorities, every hz ticks. 365 * MP-safe, called without the Giant mutex. 366 */ 367 /* ARGSUSED */ 368 static void 369 schedcpu(void) 370 { 371 register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 372 struct thread *td; 373 struct proc *p; 374 struct td_sched *ts; 375 int awake, realstathz; 376 377 realstathz = stathz ? stathz : hz; 378 sx_slock(&allproc_lock); 379 FOREACH_PROC_IN_SYSTEM(p) { 380 PROC_SLOCK(p); 381 /* 382 * Increment time in/out of memory. We ignore overflow; with 383 * 16-bit int's (remember them?) overflow takes 45 days. 384 */ 385 p->p_swtime++; 386 FOREACH_THREAD_IN_PROC(p, td) { 387 awake = 0; 388 thread_lock(td); 389 ts = td->td_sched; 390 /* 391 * Increment sleep time (if sleeping). We 392 * ignore overflow, as above. 393 */ 394 /* 395 * The td_sched slptimes are not touched in wakeup 396 * because the thread may not HAVE everything in 397 * memory? XXX I think this is out of date. 398 */ 399 if (TD_ON_RUNQ(td)) { 400 awake = 1; 401 ts->ts_flags &= ~TSF_DIDRUN; 402 } else if (TD_IS_RUNNING(td)) { 403 awake = 1; 404 /* Do not clear TSF_DIDRUN */ 405 } else if (ts->ts_flags & TSF_DIDRUN) { 406 awake = 1; 407 ts->ts_flags &= ~TSF_DIDRUN; 408 } 409 410 /* 411 * ts_pctcpu is only for ps and ttyinfo(). 412 * Do it per td_sched, and add them up at the end? 413 * XXXKSE 414 */ 415 ts->ts_pctcpu = (ts->ts_pctcpu * ccpu) >> FSHIFT; 416 /* 417 * If the td_sched has been idle the entire second, 418 * stop recalculating its priority until 419 * it wakes up. 420 */ 421 if (ts->ts_cpticks != 0) { 422 #if (FSHIFT >= CCPU_SHIFT) 423 ts->ts_pctcpu += (realstathz == 100) 424 ? ((fixpt_t) ts->ts_cpticks) << 425 (FSHIFT - CCPU_SHIFT) : 426 100 * (((fixpt_t) ts->ts_cpticks) 427 << (FSHIFT - CCPU_SHIFT)) / realstathz; 428 #else 429 ts->ts_pctcpu += ((FSCALE - ccpu) * 430 (ts->ts_cpticks * 431 FSCALE / realstathz)) >> FSHIFT; 432 #endif 433 ts->ts_cpticks = 0; 434 } 435 /* 436 * If there are ANY running threads in this process, 437 * then don't count it as sleeping. 438 XXX this is broken 439 440 */ 441 if (awake) { 442 if (td->td_slptime > 1) { 443 /* 444 * In an ideal world, this should not 445 * happen, because whoever woke us 446 * up from the long sleep should have 447 * unwound the slptime and reset our 448 * priority before we run at the stale 449 * priority. Should KASSERT at some 450 * point when all the cases are fixed. 451 */ 452 updatepri(td); 453 } 454 td->td_slptime = 0; 455 } else 456 td->td_slptime++; 457 if (td->td_slptime > 1) { 458 thread_unlock(td); 459 continue; 460 } 461 td->td_estcpu = decay_cpu(loadfac, td->td_estcpu); 462 resetpriority(td); 463 resetpriority_thread(td); 464 thread_unlock(td); 465 } /* end of thread loop */ 466 PROC_SUNLOCK(p); 467 } /* end of process loop */ 468 sx_sunlock(&allproc_lock); 469 } 470 471 /* 472 * Main loop for a kthread that executes schedcpu once a second. 473 */ 474 static void 475 schedcpu_thread(void) 476 { 477 478 for (;;) { 479 schedcpu(); 480 pause("-", hz); 481 } 482 } 483 484 /* 485 * Recalculate the priority of a process after it has slept for a while. 486 * For all load averages >= 1 and max td_estcpu of 255, sleeping for at 487 * least six times the loadfactor will decay td_estcpu to zero. 488 */ 489 static void 490 updatepri(struct thread *td) 491 { 492 register fixpt_t loadfac; 493 register unsigned int newcpu; 494 495 loadfac = loadfactor(averunnable.ldavg[0]); 496 if (td->td_slptime > 5 * loadfac) 497 td->td_estcpu = 0; 498 else { 499 newcpu = td->td_estcpu; 500 td->td_slptime--; /* was incremented in schedcpu() */ 501 while (newcpu && --td->td_slptime) 502 newcpu = decay_cpu(loadfac, newcpu); 503 td->td_estcpu = newcpu; 504 } 505 } 506 507 /* 508 * Compute the priority of a process when running in user mode. 509 * Arrange to reschedule if the resulting priority is better 510 * than that of the current process. 511 */ 512 static void 513 resetpriority(struct thread *td) 514 { 515 register unsigned int newpriority; 516 517 if (td->td_pri_class == PRI_TIMESHARE) { 518 newpriority = PUSER + td->td_estcpu / INVERSE_ESTCPU_WEIGHT + 519 NICE_WEIGHT * (td->td_proc->p_nice - PRIO_MIN); 520 newpriority = min(max(newpriority, PRI_MIN_TIMESHARE), 521 PRI_MAX_TIMESHARE); 522 sched_user_prio(td, newpriority); 523 } 524 } 525 526 /* 527 * Update the thread's priority when the associated process's user 528 * priority changes. 529 */ 530 static void 531 resetpriority_thread(struct thread *td) 532 { 533 534 /* Only change threads with a time sharing user priority. */ 535 if (td->td_priority < PRI_MIN_TIMESHARE || 536 td->td_priority > PRI_MAX_TIMESHARE) 537 return; 538 539 /* XXX the whole needresched thing is broken, but not silly. */ 540 maybe_resched(td); 541 542 sched_prio(td, td->td_user_pri); 543 } 544 545 /* ARGSUSED */ 546 static void 547 sched_setup(void *dummy) 548 { 549 setup_runqs(); 550 551 if (sched_quantum == 0) 552 sched_quantum = SCHED_QUANTUM; 553 hogticks = 2 * sched_quantum; 554 555 callout_init(&roundrobin_callout, CALLOUT_MPSAFE); 556 557 /* Kick off timeout driven events by calling first time. */ 558 roundrobin(NULL); 559 560 /* Account for thread0. */ 561 sched_load_add(); 562 } 563 564 /* External interfaces start here */ 565 /* 566 * Very early in the boot some setup of scheduler-specific 567 * parts of proc0 and of some scheduler resources needs to be done. 568 * Called from: 569 * proc0_init() 570 */ 571 void 572 schedinit(void) 573 { 574 /* 575 * Set up the scheduler specific parts of proc0. 576 */ 577 proc0.p_sched = NULL; /* XXX */ 578 thread0.td_sched = &td_sched0; 579 thread0.td_lock = &sched_lock; 580 td_sched0.ts_thread = &thread0; 581 } 582 583 int 584 sched_runnable(void) 585 { 586 #ifdef SMP 587 return runq_check(&runq) + runq_check(&runq_pcpu[PCPU_GET(cpuid)]); 588 #else 589 return runq_check(&runq); 590 #endif 591 } 592 593 int 594 sched_rr_interval(void) 595 { 596 if (sched_quantum == 0) 597 sched_quantum = SCHED_QUANTUM; 598 return (sched_quantum); 599 } 600 601 /* 602 * We adjust the priority of the current process. The priority of 603 * a process gets worse as it accumulates CPU time. The cpu usage 604 * estimator (td_estcpu) is increased here. resetpriority() will 605 * compute a different priority each time td_estcpu increases by 606 * INVERSE_ESTCPU_WEIGHT 607 * (until MAXPRI is reached). The cpu usage estimator ramps up 608 * quite quickly when the process is running (linearly), and decays 609 * away exponentially, at a rate which is proportionally slower when 610 * the system is busy. The basic principle is that the system will 611 * 90% forget that the process used a lot of CPU time in 5 * loadav 612 * seconds. This causes the system to favor processes which haven't 613 * run much recently, and to round-robin among other processes. 614 */ 615 void 616 sched_clock(struct thread *td) 617 { 618 struct td_sched *ts; 619 620 THREAD_LOCK_ASSERT(td, MA_OWNED); 621 ts = td->td_sched; 622 623 ts->ts_cpticks++; 624 td->td_estcpu = ESTCPULIM(td->td_estcpu + 1); 625 if ((td->td_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) { 626 resetpriority(td); 627 resetpriority_thread(td); 628 } 629 } 630 631 /* 632 * charge childs scheduling cpu usage to parent. 633 */ 634 void 635 sched_exit(struct proc *p, struct thread *td) 636 { 637 638 CTR3(KTR_SCHED, "sched_exit: %p(%s) prio %d", 639 td, td->td_proc->p_comm, td->td_priority); 640 PROC_SLOCK_ASSERT(p, MA_OWNED); 641 sched_exit_thread(FIRST_THREAD_IN_PROC(p), td); 642 } 643 644 void 645 sched_exit_thread(struct thread *td, struct thread *child) 646 { 647 648 CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d", 649 child, child->td_proc->p_comm, child->td_priority); 650 thread_lock(td); 651 td->td_estcpu = ESTCPULIM(td->td_estcpu + child->td_estcpu); 652 thread_unlock(td); 653 mtx_lock_spin(&sched_lock); 654 if ((child->td_proc->p_flag & P_NOLOAD) == 0) 655 sched_load_rem(); 656 mtx_unlock_spin(&sched_lock); 657 } 658 659 void 660 sched_fork(struct thread *td, struct thread *childtd) 661 { 662 sched_fork_thread(td, childtd); 663 } 664 665 void 666 sched_fork_thread(struct thread *td, struct thread *childtd) 667 { 668 childtd->td_estcpu = td->td_estcpu; 669 childtd->td_lock = &sched_lock; 670 sched_newthread(childtd); 671 } 672 673 void 674 sched_nice(struct proc *p, int nice) 675 { 676 struct thread *td; 677 678 PROC_LOCK_ASSERT(p, MA_OWNED); 679 PROC_SLOCK_ASSERT(p, MA_OWNED); 680 p->p_nice = nice; 681 FOREACH_THREAD_IN_PROC(p, td) { 682 thread_lock(td); 683 resetpriority(td); 684 resetpriority_thread(td); 685 thread_unlock(td); 686 } 687 } 688 689 void 690 sched_class(struct thread *td, int class) 691 { 692 THREAD_LOCK_ASSERT(td, MA_OWNED); 693 td->td_pri_class = class; 694 } 695 696 /* 697 * Adjust the priority of a thread. 698 */ 699 static void 700 sched_priority(struct thread *td, u_char prio) 701 { 702 CTR6(KTR_SCHED, "sched_prio: %p(%s) prio %d newprio %d by %p(%s)", 703 td, td->td_proc->p_comm, td->td_priority, prio, curthread, 704 curthread->td_proc->p_comm); 705 706 THREAD_LOCK_ASSERT(td, MA_OWNED); 707 if (td->td_priority == prio) 708 return; 709 td->td_priority = prio; 710 if (TD_ON_RUNQ(td) && 711 td->td_sched->ts_rqindex != (prio / RQ_PPQ)) { 712 sched_rem(td); 713 sched_add(td, SRQ_BORING); 714 } 715 } 716 717 /* 718 * Update a thread's priority when it is lent another thread's 719 * priority. 720 */ 721 void 722 sched_lend_prio(struct thread *td, u_char prio) 723 { 724 725 td->td_flags |= TDF_BORROWING; 726 sched_priority(td, prio); 727 } 728 729 /* 730 * Restore a thread's priority when priority propagation is 731 * over. The prio argument is the minimum priority the thread 732 * needs to have to satisfy other possible priority lending 733 * requests. If the thread's regulary priority is less 734 * important than prio the thread will keep a priority boost 735 * of prio. 736 */ 737 void 738 sched_unlend_prio(struct thread *td, u_char prio) 739 { 740 u_char base_pri; 741 742 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 743 td->td_base_pri <= PRI_MAX_TIMESHARE) 744 base_pri = td->td_user_pri; 745 else 746 base_pri = td->td_base_pri; 747 if (prio >= base_pri) { 748 td->td_flags &= ~TDF_BORROWING; 749 sched_prio(td, base_pri); 750 } else 751 sched_lend_prio(td, prio); 752 } 753 754 void 755 sched_prio(struct thread *td, u_char prio) 756 { 757 u_char oldprio; 758 759 /* First, update the base priority. */ 760 td->td_base_pri = prio; 761 762 /* 763 * If the thread is borrowing another thread's priority, don't ever 764 * lower the priority. 765 */ 766 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 767 return; 768 769 /* Change the real priority. */ 770 oldprio = td->td_priority; 771 sched_priority(td, prio); 772 773 /* 774 * If the thread is on a turnstile, then let the turnstile update 775 * its state. 776 */ 777 if (TD_ON_LOCK(td) && oldprio != prio) 778 turnstile_adjust(td, oldprio); 779 } 780 781 void 782 sched_user_prio(struct thread *td, u_char prio) 783 { 784 u_char oldprio; 785 786 td->td_base_user_pri = prio; 787 if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio) 788 return; 789 oldprio = td->td_user_pri; 790 td->td_user_pri = prio; 791 792 if (TD_ON_UPILOCK(td) && oldprio != prio) 793 umtx_pi_adjust(td, oldprio); 794 } 795 796 void 797 sched_lend_user_prio(struct thread *td, u_char prio) 798 { 799 u_char oldprio; 800 801 td->td_flags |= TDF_UBORROWING; 802 803 oldprio = td->td_user_pri; 804 td->td_user_pri = prio; 805 806 if (TD_ON_UPILOCK(td) && oldprio != prio) 807 umtx_pi_adjust(td, oldprio); 808 } 809 810 void 811 sched_unlend_user_prio(struct thread *td, u_char prio) 812 { 813 u_char base_pri; 814 815 base_pri = td->td_base_user_pri; 816 if (prio >= base_pri) { 817 td->td_flags &= ~TDF_UBORROWING; 818 sched_user_prio(td, base_pri); 819 } else 820 sched_lend_user_prio(td, prio); 821 } 822 823 void 824 sched_sleep(struct thread *td) 825 { 826 827 THREAD_LOCK_ASSERT(td, MA_OWNED); 828 td->td_slptime = 0; 829 } 830 831 void 832 sched_switch(struct thread *td, struct thread *newtd, int flags) 833 { 834 struct td_sched *ts; 835 struct proc *p; 836 837 ts = td->td_sched; 838 p = td->td_proc; 839 840 THREAD_LOCK_ASSERT(td, MA_OWNED); 841 /* 842 * Switch to the sched lock to fix things up and pick 843 * a new thread. 844 */ 845 if (td->td_lock != &sched_lock) { 846 mtx_lock_spin(&sched_lock); 847 thread_unlock(td); 848 } 849 850 if ((p->p_flag & P_NOLOAD) == 0) 851 sched_load_rem(); 852 853 if (newtd) 854 newtd->td_flags |= (td->td_flags & TDF_NEEDRESCHED); 855 856 td->td_lastcpu = td->td_oncpu; 857 td->td_flags &= ~TDF_NEEDRESCHED; 858 td->td_owepreempt = 0; 859 td->td_oncpu = NOCPU; 860 /* 861 * At the last moment, if this thread is still marked RUNNING, 862 * then put it back on the run queue as it has not been suspended 863 * or stopped or any thing else similar. We never put the idle 864 * threads on the run queue, however. 865 */ 866 if (td->td_flags & TDF_IDLETD) { 867 TD_SET_CAN_RUN(td); 868 #ifdef SMP 869 idle_cpus_mask &= ~PCPU_GET(cpumask); 870 #endif 871 } else { 872 if (TD_IS_RUNNING(td)) { 873 /* Put us back on the run queue. */ 874 sched_add(td, (flags & SW_PREEMPT) ? 875 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 876 SRQ_OURSELF|SRQ_YIELDING); 877 } 878 } 879 if (newtd) { 880 /* 881 * The thread we are about to run needs to be counted 882 * as if it had been added to the run queue and selected. 883 * It came from: 884 * * A preemption 885 * * An upcall 886 * * A followon 887 */ 888 KASSERT((newtd->td_inhibitors == 0), 889 ("trying to run inhibited thread")); 890 newtd->td_sched->ts_flags |= TSF_DIDRUN; 891 TD_SET_RUNNING(newtd); 892 if ((newtd->td_proc->p_flag & P_NOLOAD) == 0) 893 sched_load_add(); 894 } else { 895 newtd = choosethread(); 896 } 897 MPASS(newtd->td_lock == &sched_lock); 898 899 if (td != newtd) { 900 #ifdef HWPMC_HOOKS 901 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 902 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 903 #endif 904 905 /* I feel sleepy */ 906 cpu_switch(td, newtd, td->td_lock); 907 /* 908 * Where am I? What year is it? 909 * We are in the same thread that went to sleep above, 910 * but any amount of time may have passed. All out context 911 * will still be available as will local variables. 912 * PCPU values however may have changed as we may have 913 * changed CPU so don't trust cached values of them. 914 * New threads will go to fork_exit() instead of here 915 * so if you change things here you may need to change 916 * things there too. 917 * If the thread above was exiting it will never wake 918 * up again here, so either it has saved everything it 919 * needed to, or the thread_wait() or wait() will 920 * need to reap it. 921 */ 922 #ifdef HWPMC_HOOKS 923 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 924 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 925 #endif 926 } 927 928 #ifdef SMP 929 if (td->td_flags & TDF_IDLETD) 930 idle_cpus_mask |= PCPU_GET(cpumask); 931 #endif 932 sched_lock.mtx_lock = (uintptr_t)td; 933 td->td_oncpu = PCPU_GET(cpuid); 934 MPASS(td->td_lock == &sched_lock); 935 } 936 937 void 938 sched_wakeup(struct thread *td) 939 { 940 THREAD_LOCK_ASSERT(td, MA_OWNED); 941 if (td->td_slptime > 1) { 942 updatepri(td); 943 resetpriority(td); 944 } 945 td->td_slptime = 0; 946 sched_add(td, SRQ_BORING); 947 } 948 949 #ifdef SMP 950 /* enable HTT_2 if you have a 2-way HTT cpu.*/ 951 static int 952 forward_wakeup(int cpunum) 953 { 954 cpumask_t map, me, dontuse; 955 cpumask_t map2; 956 struct pcpu *pc; 957 cpumask_t id, map3; 958 959 mtx_assert(&sched_lock, MA_OWNED); 960 961 CTR0(KTR_RUNQ, "forward_wakeup()"); 962 963 if ((!forward_wakeup_enabled) || 964 (forward_wakeup_use_mask == 0 && forward_wakeup_use_loop == 0)) 965 return (0); 966 if (!smp_started || cold || panicstr) 967 return (0); 968 969 forward_wakeups_requested++; 970 971 /* 972 * check the idle mask we received against what we calculated before 973 * in the old version. 974 */ 975 me = PCPU_GET(cpumask); 976 /* 977 * don't bother if we should be doing it ourself.. 978 */ 979 if ((me & idle_cpus_mask) && (cpunum == NOCPU || me == (1 << cpunum))) 980 return (0); 981 982 dontuse = me | stopped_cpus | hlt_cpus_mask; 983 map3 = 0; 984 if (forward_wakeup_use_loop) { 985 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) { 986 id = pc->pc_cpumask; 987 if ( (id & dontuse) == 0 && 988 pc->pc_curthread == pc->pc_idlethread) { 989 map3 |= id; 990 } 991 } 992 } 993 994 if (forward_wakeup_use_mask) { 995 map = 0; 996 map = idle_cpus_mask & ~dontuse; 997 998 /* If they are both on, compare and use loop if different */ 999 if (forward_wakeup_use_loop) { 1000 if (map != map3) { 1001 printf("map (%02X) != map3 (%02X)\n", 1002 map, map3); 1003 map = map3; 1004 } 1005 } 1006 } else { 1007 map = map3; 1008 } 1009 /* If we only allow a specific CPU, then mask off all the others */ 1010 if (cpunum != NOCPU) { 1011 KASSERT((cpunum <= mp_maxcpus),("forward_wakeup: bad cpunum.")); 1012 map &= (1 << cpunum); 1013 } else { 1014 /* Try choose an idle die. */ 1015 if (forward_wakeup_use_htt) { 1016 map2 = (map & (map >> 1)) & 0x5555; 1017 if (map2) { 1018 map = map2; 1019 } 1020 } 1021 1022 /* set only one bit */ 1023 if (forward_wakeup_use_single) { 1024 map = map & ((~map) + 1); 1025 } 1026 } 1027 if (map) { 1028 forward_wakeups_delivered++; 1029 ipi_selected(map, IPI_AST); 1030 return (1); 1031 } 1032 if (cpunum == NOCPU) 1033 printf("forward_wakeup: Idle processor not found\n"); 1034 return (0); 1035 } 1036 #endif 1037 1038 #ifdef SMP 1039 static void kick_other_cpu(int pri,int cpuid); 1040 1041 static void 1042 kick_other_cpu(int pri,int cpuid) 1043 { 1044 struct pcpu * pcpu = pcpu_find(cpuid); 1045 int cpri = pcpu->pc_curthread->td_priority; 1046 1047 if (idle_cpus_mask & pcpu->pc_cpumask) { 1048 forward_wakeups_delivered++; 1049 ipi_selected(pcpu->pc_cpumask, IPI_AST); 1050 return; 1051 } 1052 1053 if (pri >= cpri) 1054 return; 1055 1056 #if defined(IPI_PREEMPTION) && defined(PREEMPTION) 1057 #if !defined(FULL_PREEMPTION) 1058 if (pri <= PRI_MAX_ITHD) 1059 #endif /* ! FULL_PREEMPTION */ 1060 { 1061 ipi_selected(pcpu->pc_cpumask, IPI_PREEMPT); 1062 return; 1063 } 1064 #endif /* defined(IPI_PREEMPTION) && defined(PREEMPTION) */ 1065 1066 pcpu->pc_curthread->td_flags |= TDF_NEEDRESCHED; 1067 ipi_selected( pcpu->pc_cpumask , IPI_AST); 1068 return; 1069 } 1070 #endif /* SMP */ 1071 1072 void 1073 sched_add(struct thread *td, int flags) 1074 #ifdef SMP 1075 { 1076 struct td_sched *ts; 1077 int forwarded = 0; 1078 int cpu; 1079 int single_cpu = 0; 1080 1081 ts = td->td_sched; 1082 THREAD_LOCK_ASSERT(td, MA_OWNED); 1083 KASSERT((td->td_inhibitors == 0), 1084 ("sched_add: trying to run inhibited thread")); 1085 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 1086 ("sched_add: bad thread state")); 1087 KASSERT(td->td_proc->p_sflag & PS_INMEM, 1088 ("sched_add: process swapped out")); 1089 CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)", 1090 td, td->td_proc->p_comm, td->td_priority, curthread, 1091 curthread->td_proc->p_comm); 1092 /* 1093 * Now that the thread is moving to the run-queue, set the lock 1094 * to the scheduler's lock. 1095 */ 1096 if (td->td_lock != &sched_lock) { 1097 mtx_lock_spin(&sched_lock); 1098 thread_lock_set(td, &sched_lock); 1099 } 1100 TD_SET_RUNQ(td); 1101 1102 if (td->td_pinned != 0) { 1103 cpu = td->td_lastcpu; 1104 ts->ts_runq = &runq_pcpu[cpu]; 1105 single_cpu = 1; 1106 CTR3(KTR_RUNQ, 1107 "sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td, cpu); 1108 } else if ((ts)->ts_flags & TSF_BOUND) { 1109 /* Find CPU from bound runq */ 1110 KASSERT(SKE_RUNQ_PCPU(ts),("sched_add: bound td_sched not on cpu runq")); 1111 cpu = ts->ts_runq - &runq_pcpu[0]; 1112 single_cpu = 1; 1113 CTR3(KTR_RUNQ, 1114 "sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td, cpu); 1115 } else { 1116 CTR2(KTR_RUNQ, 1117 "sched_add: adding td_sched:%p (td:%p) to gbl runq", ts, td); 1118 cpu = NOCPU; 1119 ts->ts_runq = &runq; 1120 } 1121 1122 if (single_cpu && (cpu != PCPU_GET(cpuid))) { 1123 kick_other_cpu(td->td_priority,cpu); 1124 } else { 1125 1126 if (!single_cpu) { 1127 cpumask_t me = PCPU_GET(cpumask); 1128 int idle = idle_cpus_mask & me; 1129 1130 if (!idle && ((flags & SRQ_INTR) == 0) && 1131 (idle_cpus_mask & ~(hlt_cpus_mask | me))) 1132 forwarded = forward_wakeup(cpu); 1133 } 1134 1135 if (!forwarded) { 1136 if ((flags & SRQ_YIELDING) == 0 && maybe_preempt(td)) 1137 return; 1138 else 1139 maybe_resched(td); 1140 } 1141 } 1142 1143 if ((td->td_proc->p_flag & P_NOLOAD) == 0) 1144 sched_load_add(); 1145 runq_add(ts->ts_runq, ts, flags); 1146 } 1147 #else /* SMP */ 1148 { 1149 struct td_sched *ts; 1150 ts = td->td_sched; 1151 THREAD_LOCK_ASSERT(td, MA_OWNED); 1152 KASSERT((td->td_inhibitors == 0), 1153 ("sched_add: trying to run inhibited thread")); 1154 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 1155 ("sched_add: bad thread state")); 1156 KASSERT(td->td_proc->p_sflag & PS_INMEM, 1157 ("sched_add: process swapped out")); 1158 CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)", 1159 td, td->td_proc->p_comm, td->td_priority, curthread, 1160 curthread->td_proc->p_comm); 1161 /* 1162 * Now that the thread is moving to the run-queue, set the lock 1163 * to the scheduler's lock. 1164 */ 1165 if (td->td_lock != &sched_lock) { 1166 mtx_lock_spin(&sched_lock); 1167 thread_lock_set(td, &sched_lock); 1168 } 1169 TD_SET_RUNQ(td); 1170 CTR2(KTR_RUNQ, "sched_add: adding td_sched:%p (td:%p) to runq", ts, td); 1171 ts->ts_runq = &runq; 1172 1173 /* 1174 * If we are yielding (on the way out anyhow) 1175 * or the thread being saved is US, 1176 * then don't try be smart about preemption 1177 * or kicking off another CPU 1178 * as it won't help and may hinder. 1179 * In the YIEDLING case, we are about to run whoever is 1180 * being put in the queue anyhow, and in the 1181 * OURSELF case, we are puting ourself on the run queue 1182 * which also only happens when we are about to yield. 1183 */ 1184 if((flags & SRQ_YIELDING) == 0) { 1185 if (maybe_preempt(td)) 1186 return; 1187 } 1188 if ((td->td_proc->p_flag & P_NOLOAD) == 0) 1189 sched_load_add(); 1190 runq_add(ts->ts_runq, ts, flags); 1191 maybe_resched(td); 1192 } 1193 #endif /* SMP */ 1194 1195 void 1196 sched_rem(struct thread *td) 1197 { 1198 struct td_sched *ts; 1199 1200 ts = td->td_sched; 1201 KASSERT(td->td_proc->p_sflag & PS_INMEM, 1202 ("sched_rem: process swapped out")); 1203 KASSERT(TD_ON_RUNQ(td), 1204 ("sched_rem: thread not on run queue")); 1205 mtx_assert(&sched_lock, MA_OWNED); 1206 CTR5(KTR_SCHED, "sched_rem: %p(%s) prio %d by %p(%s)", 1207 td, td->td_proc->p_comm, td->td_priority, curthread, 1208 curthread->td_proc->p_comm); 1209 1210 if ((td->td_proc->p_flag & P_NOLOAD) == 0) 1211 sched_load_rem(); 1212 runq_remove(ts->ts_runq, ts); 1213 TD_SET_CAN_RUN(td); 1214 } 1215 1216 /* 1217 * Select threads to run. 1218 * Notice that the running threads still consume a slot. 1219 */ 1220 struct thread * 1221 sched_choose(void) 1222 { 1223 struct td_sched *ts; 1224 struct runq *rq; 1225 1226 mtx_assert(&sched_lock, MA_OWNED); 1227 #ifdef SMP 1228 struct td_sched *kecpu; 1229 1230 rq = &runq; 1231 ts = runq_choose(&runq); 1232 kecpu = runq_choose(&runq_pcpu[PCPU_GET(cpuid)]); 1233 1234 if (ts == NULL || 1235 (kecpu != NULL && 1236 kecpu->ts_thread->td_priority < ts->ts_thread->td_priority)) { 1237 CTR2(KTR_RUNQ, "choosing td_sched %p from pcpu runq %d", kecpu, 1238 PCPU_GET(cpuid)); 1239 ts = kecpu; 1240 rq = &runq_pcpu[PCPU_GET(cpuid)]; 1241 } else { 1242 CTR1(KTR_RUNQ, "choosing td_sched %p from main runq", ts); 1243 } 1244 1245 #else 1246 rq = &runq; 1247 ts = runq_choose(&runq); 1248 #endif 1249 1250 if (ts) { 1251 runq_remove(rq, ts); 1252 ts->ts_flags |= TSF_DIDRUN; 1253 1254 KASSERT(ts->ts_thread->td_proc->p_sflag & PS_INMEM, 1255 ("sched_choose: process swapped out")); 1256 return (ts->ts_thread); 1257 } 1258 return (PCPU_GET(idlethread)); 1259 } 1260 1261 void 1262 sched_userret(struct thread *td) 1263 { 1264 /* 1265 * XXX we cheat slightly on the locking here to avoid locking in 1266 * the usual case. Setting td_priority here is essentially an 1267 * incomplete workaround for not setting it properly elsewhere. 1268 * Now that some interrupt handlers are threads, not setting it 1269 * properly elsewhere can clobber it in the window between setting 1270 * it here and returning to user mode, so don't waste time setting 1271 * it perfectly here. 1272 */ 1273 KASSERT((td->td_flags & TDF_BORROWING) == 0, 1274 ("thread with borrowed priority returning to userland")); 1275 if (td->td_priority != td->td_user_pri) { 1276 thread_lock(td); 1277 td->td_priority = td->td_user_pri; 1278 td->td_base_pri = td->td_user_pri; 1279 thread_unlock(td); 1280 } 1281 } 1282 1283 void 1284 sched_bind(struct thread *td, int cpu) 1285 { 1286 struct td_sched *ts; 1287 1288 THREAD_LOCK_ASSERT(td, MA_OWNED); 1289 KASSERT(TD_IS_RUNNING(td), 1290 ("sched_bind: cannot bind non-running thread")); 1291 1292 ts = td->td_sched; 1293 1294 ts->ts_flags |= TSF_BOUND; 1295 #ifdef SMP 1296 ts->ts_runq = &runq_pcpu[cpu]; 1297 if (PCPU_GET(cpuid) == cpu) 1298 return; 1299 1300 mi_switch(SW_VOL, NULL); 1301 #endif 1302 } 1303 1304 void 1305 sched_unbind(struct thread* td) 1306 { 1307 THREAD_LOCK_ASSERT(td, MA_OWNED); 1308 td->td_sched->ts_flags &= ~TSF_BOUND; 1309 } 1310 1311 int 1312 sched_is_bound(struct thread *td) 1313 { 1314 THREAD_LOCK_ASSERT(td, MA_OWNED); 1315 return (td->td_sched->ts_flags & TSF_BOUND); 1316 } 1317 1318 void 1319 sched_relinquish(struct thread *td) 1320 { 1321 thread_lock(td); 1322 if (td->td_pri_class == PRI_TIMESHARE) 1323 sched_prio(td, PRI_MAX_TIMESHARE); 1324 SCHED_STAT_INC(switch_relinquish); 1325 mi_switch(SW_VOL, NULL); 1326 thread_unlock(td); 1327 } 1328 1329 int 1330 sched_load(void) 1331 { 1332 return (sched_tdcnt); 1333 } 1334 1335 int 1336 sched_sizeof_proc(void) 1337 { 1338 return (sizeof(struct proc)); 1339 } 1340 1341 int 1342 sched_sizeof_thread(void) 1343 { 1344 return (sizeof(struct thread) + sizeof(struct td_sched)); 1345 } 1346 1347 fixpt_t 1348 sched_pctcpu(struct thread *td) 1349 { 1350 struct td_sched *ts; 1351 1352 ts = td->td_sched; 1353 return (ts->ts_pctcpu); 1354 } 1355 1356 void 1357 sched_tick(void) 1358 { 1359 } 1360 1361 /* 1362 * The actual idle process. 1363 */ 1364 void 1365 sched_idletd(void *dummy) 1366 { 1367 struct proc *p; 1368 struct thread *td; 1369 1370 td = curthread; 1371 p = td->td_proc; 1372 for (;;) { 1373 mtx_assert(&Giant, MA_NOTOWNED); 1374 1375 while (sched_runnable() == 0) 1376 cpu_idle(); 1377 1378 mtx_lock_spin(&sched_lock); 1379 mi_switch(SW_VOL, NULL); 1380 mtx_unlock_spin(&sched_lock); 1381 } 1382 } 1383 1384 /* 1385 * A CPU is entering for the first time or a thread is exiting. 1386 */ 1387 void 1388 sched_throw(struct thread *td) 1389 { 1390 /* 1391 * Correct spinlock nesting. The idle thread context that we are 1392 * borrowing was created so that it would start out with a single 1393 * spin lock (sched_lock) held in fork_trampoline(). Since we've 1394 * explicitly acquired locks in this function, the nesting count 1395 * is now 2 rather than 1. Since we are nested, calling 1396 * spinlock_exit() will simply adjust the counts without allowing 1397 * spin lock using code to interrupt us. 1398 */ 1399 if (td == NULL) { 1400 mtx_lock_spin(&sched_lock); 1401 spinlock_exit(); 1402 } else { 1403 MPASS(td->td_lock == &sched_lock); 1404 } 1405 mtx_assert(&sched_lock, MA_OWNED); 1406 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 1407 PCPU_SET(switchtime, cpu_ticks()); 1408 PCPU_SET(switchticks, ticks); 1409 cpu_throw(td, choosethread()); /* doesn't return */ 1410 } 1411 1412 void 1413 sched_fork_exit(struct thread *td) 1414 { 1415 1416 /* 1417 * Finish setting up thread glue so that it begins execution in a 1418 * non-nested critical section with sched_lock held but not recursed. 1419 */ 1420 td->td_oncpu = PCPU_GET(cpuid); 1421 sched_lock.mtx_lock = (uintptr_t)td; 1422 THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED); 1423 } 1424 1425 #define KERN_SWITCH_INCLUDE 1 1426 #include "kern/kern_switch.c" 1427