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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_synch.c 8.9 (Berkeley) 5/19/95 39 * $FreeBSD$ 40 */ 41 42 #include "opt_ddb.h" 43 #include "opt_ktrace.h" 44 #ifdef __i386__ 45 #include "opt_swtch.h" 46 #endif 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/condvar.h> 51 #include <sys/kernel.h> 52 #include <sys/ktr.h> 53 #include <sys/lock.h> 54 #include <sys/mutex.h> 55 #include <sys/proc.h> 56 #include <sys/resourcevar.h> 57 #include <sys/sched.h> 58 #include <sys/signalvar.h> 59 #include <sys/smp.h> 60 #include <sys/sx.h> 61 #include <sys/sysctl.h> 62 #include <sys/sysproto.h> 63 #include <sys/vmmeter.h> 64 #ifdef DDB 65 #include <ddb/ddb.h> 66 #endif 67 #ifdef KTRACE 68 #include <sys/uio.h> 69 #include <sys/ktrace.h> 70 #endif 71 72 #include <machine/cpu.h> 73 #ifdef SWTCH_OPTIM_STATS 74 #include <machine/md_var.h> 75 #endif 76 77 static void sched_setup(void *dummy); 78 SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL) 79 80 int hogticks; 81 int lbolt; 82 83 static struct callout loadav_callout; 84 static struct callout lbolt_callout; 85 86 struct loadavg averunnable = 87 { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */ 88 /* 89 * Constants for averages over 1, 5, and 15 minutes 90 * when sampling at 5 second intervals. 91 */ 92 static fixpt_t cexp[3] = { 93 0.9200444146293232 * FSCALE, /* exp(-1/12) */ 94 0.9834714538216174 * FSCALE, /* exp(-1/60) */ 95 0.9944598480048967 * FSCALE, /* exp(-1/180) */ 96 }; 97 98 /* kernel uses `FSCALE', userland (SHOULD) use kern.fscale */ 99 static int fscale __unused = FSCALE; 100 SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, ""); 101 102 static void endtsleep(void *); 103 static void loadav(void *arg); 104 static void lboltcb(void *arg); 105 106 /* 107 * We're only looking at 7 bits of the address; everything is 108 * aligned to 4, lots of things are aligned to greater powers 109 * of 2. Shift right by 8, i.e. drop the bottom 256 worth. 110 */ 111 #define TABLESIZE 128 112 static TAILQ_HEAD(slpquehead, thread) slpque[TABLESIZE]; 113 #define LOOKUP(x) (((intptr_t)(x) >> 8) & (TABLESIZE - 1)) 114 115 void 116 sleepinit(void) 117 { 118 int i; 119 120 hogticks = (hz / 10) * 2; /* Default only. */ 121 for (i = 0; i < TABLESIZE; i++) 122 TAILQ_INIT(&slpque[i]); 123 } 124 125 /* 126 * General sleep call. Suspends the current process until a wakeup is 127 * performed on the specified identifier. The process will then be made 128 * runnable with the specified priority. Sleeps at most timo/hz seconds 129 * (0 means no timeout). If pri includes PCATCH flag, signals are checked 130 * before and after sleeping, else signals are not checked. Returns 0 if 131 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a 132 * signal needs to be delivered, ERESTART is returned if the current system 133 * call should be restarted if possible, and EINTR is returned if the system 134 * call should be interrupted by the signal (return EINTR). 135 * 136 * The mutex argument is exited before the caller is suspended, and 137 * entered before msleep returns. If priority includes the PDROP 138 * flag the mutex is not entered before returning. 139 */ 140 141 int 142 msleep(ident, mtx, priority, wmesg, timo) 143 void *ident; 144 struct mtx *mtx; 145 int priority, timo; 146 const char *wmesg; 147 { 148 struct thread *td = curthread; 149 struct proc *p = td->td_proc; 150 int sig, catch = priority & PCATCH; 151 int rval = 0; 152 WITNESS_SAVE_DECL(mtx); 153 154 #ifdef KTRACE 155 if (KTRPOINT(td, KTR_CSW)) 156 ktrcsw(1, 0); 157 #endif 158 /* XXX: mtx == NULL ?? */ 159 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &mtx->mtx_object, 160 "Sleeping on \"%s\"", wmesg); 161 KASSERT(timo != 0 || mtx_owned(&Giant) || mtx != NULL, 162 ("sleeping without a mutex")); 163 /* 164 * If we are capable of async syscalls and there isn't already 165 * another one ready to return, start a new thread 166 * and queue it as ready to run. Note that there is danger here 167 * because we need to make sure that we don't sleep allocating 168 * the thread (recursion here might be bad). 169 */ 170 mtx_lock_spin(&sched_lock); 171 if (p->p_flag & P_THREADED || p->p_numthreads > 1) { 172 /* 173 * Just don't bother if we are exiting 174 * and not the exiting thread or thread was marked as 175 * interrupted. 176 */ 177 if (catch && 178 (((p->p_flag & P_WEXIT) && (p->p_singlethread != td)) || 179 (td->td_flags & TDF_INTERRUPT))) { 180 td->td_flags &= ~TDF_INTERRUPT; 181 mtx_unlock_spin(&sched_lock); 182 return (EINTR); 183 } 184 } 185 if (cold ) { 186 /* 187 * During autoconfiguration, just give interrupts 188 * a chance, then just return. 189 * Don't run any other procs or panic below, 190 * in case this is the idle process and already asleep. 191 */ 192 if (mtx != NULL && priority & PDROP) 193 mtx_unlock(mtx); 194 mtx_unlock_spin(&sched_lock); 195 return (0); 196 } 197 198 DROP_GIANT(); 199 200 if (mtx != NULL) { 201 mtx_assert(mtx, MA_OWNED | MA_NOTRECURSED); 202 WITNESS_SAVE(&mtx->mtx_object, mtx); 203 mtx_unlock(mtx); 204 if (priority & PDROP) 205 mtx = NULL; 206 } 207 208 KASSERT(p != NULL, ("msleep1")); 209 KASSERT(ident != NULL && TD_IS_RUNNING(td), ("msleep")); 210 211 CTR5(KTR_PROC, "msleep: thread %p (pid %d, %s) on %s (%p)", 212 td, p->p_pid, p->p_comm, wmesg, ident); 213 214 td->td_wchan = ident; 215 td->td_wmesg = wmesg; 216 TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], td, td_slpq); 217 TD_SET_ON_SLEEPQ(td); 218 if (timo) 219 callout_reset(&td->td_slpcallout, timo, endtsleep, td); 220 /* 221 * We put ourselves on the sleep queue and start our timeout 222 * before calling thread_suspend_check, as we could stop there, and 223 * a wakeup or a SIGCONT (or both) could occur while we were stopped. 224 * without resuming us, thus we must be ready for sleep 225 * when cursig is called. If the wakeup happens while we're 226 * stopped, td->td_wchan will be 0 upon return from cursig. 227 */ 228 if (catch) { 229 CTR3(KTR_PROC, "msleep caught: thread %p (pid %d, %s)", td, 230 p->p_pid, p->p_comm); 231 td->td_flags |= TDF_SINTR; 232 mtx_unlock_spin(&sched_lock); 233 PROC_LOCK(p); 234 mtx_lock(&p->p_sigacts->ps_mtx); 235 sig = cursig(td); 236 mtx_unlock(&p->p_sigacts->ps_mtx); 237 if (sig == 0 && thread_suspend_check(1)) 238 sig = SIGSTOP; 239 mtx_lock_spin(&sched_lock); 240 PROC_UNLOCK(p); 241 if (sig != 0) { 242 if (TD_ON_SLEEPQ(td)) 243 unsleep(td); 244 } else if (!TD_ON_SLEEPQ(td)) 245 catch = 0; 246 } else 247 sig = 0; 248 249 /* 250 * Let the scheduler know we're about to voluntarily go to sleep. 251 */ 252 sched_sleep(td, priority & PRIMASK); 253 254 if (TD_ON_SLEEPQ(td)) { 255 p->p_stats->p_ru.ru_nvcsw++; 256 TD_SET_SLEEPING(td); 257 mi_switch(); 258 } 259 /* 260 * We're awake from voluntary sleep. 261 */ 262 CTR3(KTR_PROC, "msleep resume: thread %p (pid %d, %s)", td, p->p_pid, 263 p->p_comm); 264 KASSERT(TD_IS_RUNNING(td), ("running but not TDS_RUNNING")); 265 td->td_flags &= ~TDF_SINTR; 266 if (td->td_flags & TDF_TIMEOUT) { 267 td->td_flags &= ~TDF_TIMEOUT; 268 if (sig == 0) 269 rval = EWOULDBLOCK; 270 } else if (td->td_flags & TDF_TIMOFAIL) { 271 td->td_flags &= ~TDF_TIMOFAIL; 272 } else if (timo && callout_stop(&td->td_slpcallout) == 0) { 273 /* 274 * This isn't supposed to be pretty. If we are here, then 275 * the endtsleep() callout is currently executing on another 276 * CPU and is either spinning on the sched_lock or will be 277 * soon. If we don't synchronize here, there is a chance 278 * that this process may msleep() again before the callout 279 * has a chance to run and the callout may end up waking up 280 * the wrong msleep(). Yuck. 281 */ 282 TD_SET_SLEEPING(td); 283 p->p_stats->p_ru.ru_nivcsw++; 284 mi_switch(); 285 td->td_flags &= ~TDF_TIMOFAIL; 286 } 287 if ((td->td_flags & TDF_INTERRUPT) && (priority & PCATCH) && 288 (rval == 0)) { 289 td->td_flags &= ~TDF_INTERRUPT; 290 rval = EINTR; 291 } 292 mtx_unlock_spin(&sched_lock); 293 294 if (rval == 0 && catch) { 295 PROC_LOCK(p); 296 /* XXX: shouldn't we always be calling cursig() */ 297 mtx_lock(&p->p_sigacts->ps_mtx); 298 if (sig != 0 || (sig = cursig(td))) { 299 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 300 rval = EINTR; 301 else 302 rval = ERESTART; 303 } 304 mtx_unlock(&p->p_sigacts->ps_mtx); 305 PROC_UNLOCK(p); 306 } 307 #ifdef KTRACE 308 if (KTRPOINT(td, KTR_CSW)) 309 ktrcsw(0, 0); 310 #endif 311 PICKUP_GIANT(); 312 if (mtx != NULL) { 313 mtx_lock(mtx); 314 WITNESS_RESTORE(&mtx->mtx_object, mtx); 315 } 316 return (rval); 317 } 318 319 /* 320 * Implement timeout for msleep() 321 * 322 * If process hasn't been awakened (wchan non-zero), 323 * set timeout flag and undo the sleep. If proc 324 * is stopped, just unsleep so it will remain stopped. 325 * MP-safe, called without the Giant mutex. 326 */ 327 static void 328 endtsleep(arg) 329 void *arg; 330 { 331 register struct thread *td = arg; 332 333 CTR3(KTR_PROC, "endtsleep: thread %p (pid %d, %s)", 334 td, td->td_proc->p_pid, td->td_proc->p_comm); 335 mtx_lock_spin(&sched_lock); 336 /* 337 * This is the other half of the synchronization with msleep() 338 * described above. If the TDS_TIMEOUT flag is set, we lost the 339 * race and just need to put the process back on the runqueue. 340 */ 341 if (TD_ON_SLEEPQ(td)) { 342 TAILQ_REMOVE(&slpque[LOOKUP(td->td_wchan)], td, td_slpq); 343 TD_CLR_ON_SLEEPQ(td); 344 td->td_flags |= TDF_TIMEOUT; 345 td->td_wmesg = NULL; 346 } else { 347 td->td_flags |= TDF_TIMOFAIL; 348 } 349 TD_CLR_SLEEPING(td); 350 setrunnable(td); 351 mtx_unlock_spin(&sched_lock); 352 } 353 354 /* 355 * Abort a thread, as if an interrupt had occured. Only abort 356 * interruptable waits (unfortunatly it isn't only safe to abort others). 357 * This is about identical to cv_abort(). 358 * Think about merging them? 359 * Also, whatever the signal code does... 360 */ 361 void 362 abortsleep(struct thread *td) 363 { 364 365 mtx_assert(&sched_lock, MA_OWNED); 366 /* 367 * If the TDF_TIMEOUT flag is set, just leave. A 368 * timeout is scheduled anyhow. 369 */ 370 if ((td->td_flags & (TDF_TIMEOUT | TDF_SINTR)) == TDF_SINTR) { 371 if (TD_ON_SLEEPQ(td)) { 372 unsleep(td); 373 TD_CLR_SLEEPING(td); 374 setrunnable(td); 375 } 376 } 377 } 378 379 /* 380 * Remove a process from its wait queue 381 */ 382 void 383 unsleep(struct thread *td) 384 { 385 386 mtx_lock_spin(&sched_lock); 387 if (TD_ON_SLEEPQ(td)) { 388 TAILQ_REMOVE(&slpque[LOOKUP(td->td_wchan)], td, td_slpq); 389 TD_CLR_ON_SLEEPQ(td); 390 td->td_wmesg = NULL; 391 } 392 mtx_unlock_spin(&sched_lock); 393 } 394 395 /* 396 * Make all processes sleeping on the specified identifier runnable. 397 */ 398 void 399 wakeup(ident) 400 register void *ident; 401 { 402 register struct slpquehead *qp; 403 register struct thread *td; 404 struct thread *ntd; 405 struct proc *p; 406 407 mtx_lock_spin(&sched_lock); 408 qp = &slpque[LOOKUP(ident)]; 409 restart: 410 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) { 411 ntd = TAILQ_NEXT(td, td_slpq); 412 if (td->td_wchan == ident) { 413 unsleep(td); 414 TD_CLR_SLEEPING(td); 415 setrunnable(td); 416 p = td->td_proc; 417 CTR3(KTR_PROC,"wakeup: thread %p (pid %d, %s)", 418 td, p->p_pid, p->p_comm); 419 goto restart; 420 } 421 } 422 mtx_unlock_spin(&sched_lock); 423 } 424 425 /* 426 * Make a process sleeping on the specified identifier runnable. 427 * May wake more than one process if a target process is currently 428 * swapped out. 429 */ 430 void 431 wakeup_one(ident) 432 register void *ident; 433 { 434 register struct slpquehead *qp; 435 register struct thread *td; 436 register struct proc *p; 437 struct thread *ntd; 438 439 mtx_lock_spin(&sched_lock); 440 qp = &slpque[LOOKUP(ident)]; 441 for (td = TAILQ_FIRST(qp); td != NULL; td = ntd) { 442 ntd = TAILQ_NEXT(td, td_slpq); 443 if (td->td_wchan == ident) { 444 unsleep(td); 445 TD_CLR_SLEEPING(td); 446 setrunnable(td); 447 p = td->td_proc; 448 CTR3(KTR_PROC,"wakeup1: thread %p (pid %d, %s)", 449 td, p->p_pid, p->p_comm); 450 break; 451 } 452 } 453 mtx_unlock_spin(&sched_lock); 454 } 455 456 /* 457 * The machine independent parts of mi_switch(). 458 */ 459 void 460 mi_switch(void) 461 { 462 struct bintime new_switchtime; 463 struct thread *td; 464 #if !defined(__alpha__) && !defined(__powerpc__) 465 struct thread *newtd; 466 #endif 467 struct proc *p; 468 u_int sched_nest; 469 470 mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED); 471 td = curthread; /* XXX */ 472 p = td->td_proc; /* XXX */ 473 KASSERT(!TD_ON_RUNQ(td), ("mi_switch: called by old code")); 474 #ifdef INVARIANTS 475 if (!TD_ON_LOCK(td) && !TD_IS_RUNNING(td)) 476 mtx_assert(&Giant, MA_NOTOWNED); 477 #endif 478 KASSERT(td->td_critnest == 1, 479 ("mi_switch: switch in a critical section")); 480 481 /* 482 * Compute the amount of time during which the current 483 * process was running, and add that to its total so far. 484 */ 485 binuptime(&new_switchtime); 486 bintime_add(&p->p_runtime, &new_switchtime); 487 bintime_sub(&p->p_runtime, PCPU_PTR(switchtime)); 488 489 #ifdef DDB 490 /* 491 * Don't perform context switches from the debugger. 492 */ 493 if (db_active) { 494 mtx_unlock_spin(&sched_lock); 495 db_print_backtrace(); 496 db_error("Context switches not allowed in the debugger."); 497 } 498 #endif 499 500 /* 501 * Check if the process exceeds its cpu resource allocation. If 502 * over max, arrange to kill the process in ast(). 503 */ 504 if (p->p_cpulimit != RLIM_INFINITY && 505 p->p_runtime.sec > p->p_cpulimit) { 506 p->p_sflag |= PS_XCPU; 507 td->td_flags |= TDF_ASTPENDING; 508 } 509 510 /* 511 * Finish up stats for outgoing thread. 512 */ 513 cnt.v_swtch++; 514 PCPU_SET(switchtime, new_switchtime); 515 CTR3(KTR_PROC, "mi_switch: old thread %p (pid %d, %s)", td, p->p_pid, 516 p->p_comm); 517 sched_nest = sched_lock.mtx_recurse; 518 if (td->td_proc->p_flag & P_THREADED) 519 thread_switchout(td); 520 sched_switchout(td); 521 522 #if !defined(__alpha__) && !defined(__powerpc__) 523 newtd = choosethread(); 524 if (td != newtd) 525 cpu_switch(td, newtd); /* SHAZAM!! */ 526 #ifdef SWTCH_OPTIM_STATS 527 else 528 stupid_switch++; 529 #endif 530 #else 531 cpu_switch(); /* SHAZAM!!*/ 532 #endif 533 534 sched_lock.mtx_recurse = sched_nest; 535 sched_lock.mtx_lock = (uintptr_t)td; 536 sched_switchin(td); 537 538 /* 539 * Start setting up stats etc. for the incoming thread. 540 * Similar code in fork_exit() is returned to by cpu_switch() 541 * in the case of a new thread/process. 542 */ 543 CTR3(KTR_PROC, "mi_switch: new thread %p (pid %d, %s)", td, p->p_pid, 544 p->p_comm); 545 if (PCPU_GET(switchtime.sec) == 0) 546 binuptime(PCPU_PTR(switchtime)); 547 PCPU_SET(switchticks, ticks); 548 549 /* 550 * Call the switchin function while still holding the scheduler lock 551 * (used by the idlezero code and the general page-zeroing code) 552 */ 553 if (td->td_switchin) 554 td->td_switchin(); 555 556 /* 557 * If the last thread was exiting, finish cleaning it up. 558 */ 559 if ((td = PCPU_GET(deadthread))) { 560 PCPU_SET(deadthread, NULL); 561 thread_stash(td); 562 } 563 } 564 565 /* 566 * Change process state to be runnable, 567 * placing it on the run queue if it is in memory, 568 * and awakening the swapper if it isn't in memory. 569 */ 570 void 571 setrunnable(struct thread *td) 572 { 573 struct proc *p = td->td_proc; 574 575 mtx_assert(&sched_lock, MA_OWNED); 576 switch (p->p_state) { 577 case PRS_ZOMBIE: 578 panic("setrunnable(1)"); 579 default: 580 break; 581 } 582 switch (td->td_state) { 583 case TDS_RUNNING: 584 case TDS_RUNQ: 585 return; 586 case TDS_INHIBITED: 587 /* 588 * If we are only inhibited because we are swapped out 589 * then arange to swap in this process. Otherwise just return. 590 */ 591 if (td->td_inhibitors != TDI_SWAPPED) 592 return; 593 /* XXX: intentional fall-through ? */ 594 case TDS_CAN_RUN: 595 break; 596 default: 597 printf("state is 0x%x", td->td_state); 598 panic("setrunnable(2)"); 599 } 600 if ((p->p_sflag & PS_INMEM) == 0) { 601 if ((p->p_sflag & PS_SWAPPINGIN) == 0) { 602 p->p_sflag |= PS_SWAPINREQ; 603 wakeup(&proc0); 604 } 605 } else 606 sched_wakeup(td); 607 } 608 609 /* 610 * Compute a tenex style load average of a quantity on 611 * 1, 5 and 15 minute intervals. 612 * XXXKSE Needs complete rewrite when correct info is available. 613 * Completely Bogus.. only works with 1:1 (but compiles ok now :-) 614 */ 615 static void 616 loadav(void *arg) 617 { 618 int i, nrun; 619 struct loadavg *avg; 620 struct proc *p; 621 struct thread *td; 622 623 avg = &averunnable; 624 sx_slock(&allproc_lock); 625 nrun = 0; 626 FOREACH_PROC_IN_SYSTEM(p) { 627 FOREACH_THREAD_IN_PROC(p, td) { 628 switch (td->td_state) { 629 case TDS_RUNQ: 630 case TDS_RUNNING: 631 if ((p->p_flag & P_NOLOAD) != 0) 632 goto nextproc; 633 nrun++; /* XXXKSE */ 634 default: 635 break; 636 } 637 nextproc: 638 continue; 639 } 640 } 641 sx_sunlock(&allproc_lock); 642 for (i = 0; i < 3; i++) 643 avg->ldavg[i] = (cexp[i] * avg->ldavg[i] + 644 nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT; 645 646 /* 647 * Schedule the next update to occur after 5 seconds, but add a 648 * random variation to avoid synchronisation with processes that 649 * run at regular intervals. 650 */ 651 callout_reset(&loadav_callout, hz * 4 + (int)(random() % (hz * 2 + 1)), 652 loadav, NULL); 653 } 654 655 static void 656 lboltcb(void *arg) 657 { 658 wakeup(&lbolt); 659 callout_reset(&lbolt_callout, hz, lboltcb, NULL); 660 } 661 662 /* ARGSUSED */ 663 static void 664 sched_setup(dummy) 665 void *dummy; 666 { 667 callout_init(&loadav_callout, 0); 668 callout_init(&lbolt_callout, 1); 669 670 /* Kick off timeout driven events by calling first time. */ 671 loadav(NULL); 672 lboltcb(NULL); 673 } 674 675 /* 676 * General purpose yield system call 677 */ 678 int 679 yield(struct thread *td, struct yield_args *uap) 680 { 681 struct ksegrp *kg = td->td_ksegrp; 682 683 mtx_assert(&Giant, MA_NOTOWNED); 684 mtx_lock_spin(&sched_lock); 685 kg->kg_proc->p_stats->p_ru.ru_nvcsw++; 686 sched_prio(td, PRI_MAX_TIMESHARE); 687 mi_switch(); 688 mtx_unlock_spin(&sched_lock); 689 td->td_retval[0] = 0; 690 691 return (0); 692 } 693 694