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