kern_switch.c revision 131927
1/* 2 * Copyright (c) 2001 Jake Burkholder <jake@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27/*** 28Here is the logic.. 29 30If there are N processors, then there are at most N KSEs (kernel 31schedulable entities) working to process threads that belong to a 32KSEGROUP (kg). If there are X of these KSEs actually running at the 33moment in question, then there are at most M (N-X) of these KSEs on 34the run queue, as running KSEs are not on the queue. 35 36Runnable threads are queued off the KSEGROUP in priority order. 37If there are M or more threads runnable, the top M threads 38(by priority) are 'preassigned' to the M KSEs not running. The KSEs take 39their priority from those threads and are put on the run queue. 40 41The last thread that had a priority high enough to have a KSE associated 42with it, AND IS ON THE RUN QUEUE is pointed to by 43kg->kg_last_assigned. If no threads queued off the KSEGROUP have KSEs 44assigned as all the available KSEs are activly running, or because there 45are no threads queued, that pointer is NULL. 46 47When a KSE is removed from the run queue to become runnable, we know 48it was associated with the highest priority thread in the queue (at the head 49of the queue). If it is also the last assigned we know M was 1 and must 50now be 0. Since the thread is no longer queued that pointer must be 51removed from it. Since we know there were no more KSEs available, 52(M was 1 and is now 0) and since we are not FREEING our KSE 53but using it, we know there are STILL no more KSEs available, we can prove 54that the next thread in the ksegrp list will not have a KSE to assign to 55it, so we can show that the pointer must be made 'invalid' (NULL). 56 57The pointer exists so that when a new thread is made runnable, it can 58have its priority compared with the last assigned thread to see if 59it should 'steal' its KSE or not.. i.e. is it 'earlier' 60on the list than that thread or later.. If it's earlier, then the KSE is 61removed from the last assigned (which is now not assigned a KSE) 62and reassigned to the new thread, which is placed earlier in the list. 63The pointer is then backed up to the previous thread (which may or may not 64be the new thread). 65 66When a thread sleeps or is removed, the KSE becomes available and if there 67are queued threads that are not assigned KSEs, the highest priority one of 68them is assigned the KSE, which is then placed back on the run queue at 69the approipriate place, and the kg->kg_last_assigned pointer is adjusted down 70to point to it. 71 72The following diagram shows 2 KSEs and 3 threads from a single process. 73 74 RUNQ: --->KSE---KSE--... (KSEs queued at priorities from threads) 75 \ \____ 76 \ \ 77 KSEGROUP---thread--thread--thread (queued in priority order) 78 \ / 79 \_______________/ 80 (last_assigned) 81 82The result of this scheme is that the M available KSEs are always 83queued at the priorities they have inherrited from the M highest priority 84threads for that KSEGROUP. If this situation changes, the KSEs are 85reassigned to keep this true. 86***/ 87 88#include <sys/cdefs.h> 89__FBSDID("$FreeBSD: head/sys/kern/kern_switch.c 131927 2004-07-10 21:36:01Z marcel $"); 90 91#include "opt_full_preemption.h" 92 93#include <sys/param.h> 94#include <sys/systm.h> 95#include <sys/kdb.h> 96#include <sys/kernel.h> 97#include <sys/ktr.h> 98#include <sys/lock.h> 99#include <sys/mutex.h> 100#include <sys/proc.h> 101#include <sys/queue.h> 102#include <sys/sched.h> 103#if defined(SMP) && (defined(__i386__) || defined(__amd64__)) 104#include <sys/smp.h> 105#endif 106#include <machine/critical.h> 107 108CTASSERT((RQB_BPW * RQB_LEN) == RQ_NQS); 109 110void panc(char *string1, char *string2); 111 112#if 0 113static void runq_readjust(struct runq *rq, struct kse *ke); 114#endif 115/************************************************************************ 116 * Functions that manipulate runnability from a thread perspective. * 117 ************************************************************************/ 118/* 119 * Select the KSE that will be run next. From that find the thread, and 120 * remove it from the KSEGRP's run queue. If there is thread clustering, 121 * this will be what does it. 122 */ 123struct thread * 124choosethread(void) 125{ 126 struct kse *ke; 127 struct thread *td; 128 struct ksegrp *kg; 129 130#if defined(SMP) && (defined(__i386__) || defined(__amd64__)) 131 if (smp_active == 0 && PCPU_GET(cpuid) != 0) { 132 /* Shutting down, run idlethread on AP's */ 133 td = PCPU_GET(idlethread); 134 ke = td->td_kse; 135 CTR1(KTR_RUNQ, "choosethread: td=%p (idle)", td); 136 ke->ke_flags |= KEF_DIDRUN; 137 TD_SET_RUNNING(td); 138 return (td); 139 } 140#endif 141 142retry: 143 ke = sched_choose(); 144 if (ke) { 145 td = ke->ke_thread; 146 KASSERT((td->td_kse == ke), ("kse/thread mismatch")); 147 kg = ke->ke_ksegrp; 148 if (td->td_proc->p_flag & P_SA) { 149 if (kg->kg_last_assigned == td) { 150 kg->kg_last_assigned = TAILQ_PREV(td, 151 threadqueue, td_runq); 152 } 153 TAILQ_REMOVE(&kg->kg_runq, td, td_runq); 154 } 155 kg->kg_runnable--; 156 CTR2(KTR_RUNQ, "choosethread: td=%p pri=%d", 157 td, td->td_priority); 158 } else { 159 /* Simulate runq_choose() having returned the idle thread */ 160 td = PCPU_GET(idlethread); 161 ke = td->td_kse; 162 CTR1(KTR_RUNQ, "choosethread: td=%p (idle)", td); 163 } 164 ke->ke_flags |= KEF_DIDRUN; 165 166 /* 167 * If we are in panic, only allow system threads, 168 * plus the one we are running in, to be run. 169 */ 170 if (panicstr && ((td->td_proc->p_flag & P_SYSTEM) == 0 && 171 (td->td_flags & TDF_INPANIC) == 0)) { 172 /* note that it is no longer on the run queue */ 173 TD_SET_CAN_RUN(td); 174 goto retry; 175 } 176 177 TD_SET_RUNNING(td); 178 return (td); 179} 180 181/* 182 * Given a surplus KSE, either assign a new runable thread to it 183 * (and put it in the run queue) or put it in the ksegrp's idle KSE list. 184 * Assumes that the original thread is not runnable. 185 */ 186void 187kse_reassign(struct kse *ke) 188{ 189 struct ksegrp *kg; 190 struct thread *td; 191 struct thread *original; 192 193 mtx_assert(&sched_lock, MA_OWNED); 194 original = ke->ke_thread; 195 KASSERT(original == NULL || TD_IS_INHIBITED(original), 196 ("reassigning KSE with runnable thread")); 197 kg = ke->ke_ksegrp; 198 if (original) 199 original->td_kse = NULL; 200 201 /* 202 * Find the first unassigned thread 203 */ 204 if ((td = kg->kg_last_assigned) != NULL) 205 td = TAILQ_NEXT(td, td_runq); 206 else 207 td = TAILQ_FIRST(&kg->kg_runq); 208 209 /* 210 * If we found one, assign it the kse, otherwise idle the kse. 211 */ 212 if (td) { 213 kg->kg_last_assigned = td; 214 td->td_kse = ke; 215 ke->ke_thread = td; 216 sched_add(td); 217 CTR2(KTR_RUNQ, "kse_reassign: ke%p -> td%p", ke, td); 218 return; 219 } 220 221 ke->ke_state = KES_IDLE; 222 ke->ke_thread = NULL; 223 TAILQ_INSERT_TAIL(&kg->kg_iq, ke, ke_kgrlist); 224 kg->kg_idle_kses++; 225 CTR1(KTR_RUNQ, "kse_reassign: ke%p on idle queue", ke); 226 return; 227} 228 229#if 0 230/* 231 * Remove a thread from its KSEGRP's run queue. 232 * This in turn may remove it from a KSE if it was already assigned 233 * to one, possibly causing a new thread to be assigned to the KSE 234 * and the KSE getting a new priority. 235 */ 236static void 237remrunqueue(struct thread *td) 238{ 239 struct thread *td2, *td3; 240 struct ksegrp *kg; 241 struct kse *ke; 242 243 mtx_assert(&sched_lock, MA_OWNED); 244 KASSERT((TD_ON_RUNQ(td)), ("remrunqueue: Bad state on run queue")); 245 kg = td->td_ksegrp; 246 ke = td->td_kse; 247 CTR1(KTR_RUNQ, "remrunqueue: td%p", td); 248 kg->kg_runnable--; 249 TD_SET_CAN_RUN(td); 250 /* 251 * If it is not a threaded process, take the shortcut. 252 */ 253 if ((td->td_proc->p_flag & P_SA) == 0) { 254 /* Bring its kse with it, leave the thread attached */ 255 sched_rem(td); 256 ke->ke_state = KES_THREAD; 257 return; 258 } 259 td3 = TAILQ_PREV(td, threadqueue, td_runq); 260 TAILQ_REMOVE(&kg->kg_runq, td, td_runq); 261 if (ke) { 262 /* 263 * This thread has been assigned to a KSE. 264 * We need to dissociate it and try assign the 265 * KSE to the next available thread. Then, we should 266 * see if we need to move the KSE in the run queues. 267 */ 268 sched_rem(td); 269 ke->ke_state = KES_THREAD; 270 td2 = kg->kg_last_assigned; 271 KASSERT((td2 != NULL), ("last assigned has wrong value")); 272 if (td2 == td) 273 kg->kg_last_assigned = td3; 274 kse_reassign(ke); 275 } 276} 277#endif 278 279/* 280 * Change the priority of a thread that is on the run queue. 281 */ 282void 283adjustrunqueue( struct thread *td, int newpri) 284{ 285 struct ksegrp *kg; 286 struct kse *ke; 287 288 mtx_assert(&sched_lock, MA_OWNED); 289 KASSERT((TD_ON_RUNQ(td)), ("adjustrunqueue: Bad state on run queue")); 290 291 ke = td->td_kse; 292 CTR1(KTR_RUNQ, "adjustrunqueue: td%p", td); 293 /* 294 * If it is not a threaded process, take the shortcut. 295 */ 296 if ((td->td_proc->p_flag & P_SA) == 0) { 297 /* We only care about the kse in the run queue. */ 298 td->td_priority = newpri; 299 if (ke->ke_rqindex != (newpri / RQ_PPQ)) { 300 sched_rem(td); 301 sched_add(td); 302 } 303 return; 304 } 305 306 /* It is a threaded process */ 307 kg = td->td_ksegrp; 308 kg->kg_runnable--; 309 TD_SET_CAN_RUN(td); 310 if (ke) { 311 if (kg->kg_last_assigned == td) { 312 kg->kg_last_assigned = 313 TAILQ_PREV(td, threadqueue, td_runq); 314 } 315 sched_rem(td); 316 } 317 TAILQ_REMOVE(&kg->kg_runq, td, td_runq); 318 td->td_priority = newpri; 319 setrunqueue(td); 320} 321 322void 323setrunqueue(struct thread *td) 324{ 325 struct kse *ke; 326 struct ksegrp *kg; 327 struct thread *td2; 328 struct thread *tda; 329 330 CTR1(KTR_RUNQ, "setrunqueue: td%p", td); 331 mtx_assert(&sched_lock, MA_OWNED); 332 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 333 ("setrunqueue: bad thread state")); 334 TD_SET_RUNQ(td); 335 kg = td->td_ksegrp; 336 kg->kg_runnable++; 337 if ((td->td_proc->p_flag & P_SA) == 0) { 338 /* 339 * Common path optimisation: Only one of everything 340 * and the KSE is always already attached. 341 * Totally ignore the ksegrp run queue. 342 */ 343 sched_add(td); 344 return; 345 } 346 347 tda = kg->kg_last_assigned; 348 if ((ke = td->td_kse) == NULL) { 349 if (kg->kg_idle_kses) { 350 /* 351 * There is a free one so it's ours for the asking.. 352 */ 353 ke = TAILQ_FIRST(&kg->kg_iq); 354 TAILQ_REMOVE(&kg->kg_iq, ke, ke_kgrlist); 355 ke->ke_state = KES_THREAD; 356 kg->kg_idle_kses--; 357 } else if (tda && (tda->td_priority > td->td_priority)) { 358 /* 359 * None free, but there is one we can commandeer. 360 */ 361 ke = tda->td_kse; 362 sched_rem(tda); 363 tda->td_kse = NULL; 364 ke->ke_thread = NULL; 365 tda = kg->kg_last_assigned = 366 TAILQ_PREV(tda, threadqueue, td_runq); 367 } 368 } else { 369 /* 370 * Temporarily disassociate so it looks like the other cases. 371 */ 372 ke->ke_thread = NULL; 373 td->td_kse = NULL; 374 } 375 376 /* 377 * Add the thread to the ksegrp's run queue at 378 * the appropriate place. 379 */ 380 TAILQ_FOREACH(td2, &kg->kg_runq, td_runq) { 381 if (td2->td_priority > td->td_priority) { 382 TAILQ_INSERT_BEFORE(td2, td, td_runq); 383 break; 384 } 385 } 386 if (td2 == NULL) { 387 /* We ran off the end of the TAILQ or it was empty. */ 388 TAILQ_INSERT_TAIL(&kg->kg_runq, td, td_runq); 389 } 390 391 /* 392 * If we have a ke to use, then put it on the run queue and 393 * If needed, readjust the last_assigned pointer. 394 */ 395 if (ke) { 396 if (tda == NULL) { 397 /* 398 * No pre-existing last assigned so whoever is first 399 * gets the KSE we brought in.. (maybe us) 400 */ 401 td2 = TAILQ_FIRST(&kg->kg_runq); 402 KASSERT((td2->td_kse == NULL), 403 ("unexpected ke present")); 404 td2->td_kse = ke; 405 ke->ke_thread = td2; 406 kg->kg_last_assigned = td2; 407 } else if (tda->td_priority > td->td_priority) { 408 /* 409 * It's ours, grab it, but last_assigned is past us 410 * so don't change it. 411 */ 412 td->td_kse = ke; 413 ke->ke_thread = td; 414 } else { 415 /* 416 * We are past last_assigned, so 417 * put the new kse on whatever is next, 418 * which may or may not be us. 419 */ 420 td2 = TAILQ_NEXT(tda, td_runq); 421 kg->kg_last_assigned = td2; 422 td2->td_kse = ke; 423 ke->ke_thread = td2; 424 } 425 sched_add(ke->ke_thread); 426 } 427} 428 429/* 430 * Kernel thread preemption implementation. Critical sections mark 431 * regions of code in which preemptions are not allowed. 432 */ 433void 434critical_enter(void) 435{ 436 struct thread *td; 437 438 td = curthread; 439 if (td->td_critnest == 0) 440 cpu_critical_enter(); 441 td->td_critnest++; 442} 443 444void 445critical_exit(void) 446{ 447 struct thread *td; 448 449 td = curthread; 450 KASSERT(td->td_critnest != 0, 451 ("critical_exit: td_critnest == 0")); 452 if (td->td_critnest == 1) { 453#ifdef PREEMPTION 454 if (td->td_flags & TDF_OWEPREEMPT) { 455 mtx_lock_spin(&sched_lock); 456 mi_switch(SW_INVOL, NULL); 457 mtx_unlock_spin(&sched_lock); 458 } 459#endif 460 td->td_critnest = 0; 461 cpu_critical_exit(); 462 } else { 463 td->td_critnest--; 464 } 465} 466 467/* 468 * This function is called when a thread is about to be put on run queue 469 * because it has been made runnable or its priority has been adjusted. It 470 * determines if the new thread should be immediately preempted to. If so, 471 * it switches to it and eventually returns true. If not, it returns false 472 * so that the caller may place the thread on an appropriate run queue. 473 */ 474int 475maybe_preempt(struct thread *td) 476{ 477#ifdef PREEMPTION 478 struct thread *ctd; 479 int cpri, pri; 480#endif 481 482 mtx_assert(&sched_lock, MA_OWNED); 483#ifdef PREEMPTION 484 /* 485 * The new thread should not preempt the current thread if any of the 486 * following conditions are true: 487 * 488 * - The current thread has a higher (numerically lower) priority. 489 * - It is too early in the boot for context switches (cold is set). 490 * - The current thread has an inhibitor set or is in the process of 491 * exiting. In this case, the current thread is about to switch 492 * out anyways, so there's no point in preempting. If we did, 493 * the current thread would not be properly resumed as well, so 494 * just avoid that whole landmine. 495 * - If the new thread's priority is not a realtime priority and 496 * the current thread's priority is not an idle priority and 497 * FULL_PREEMPTION is disabled. 498 * 499 * If all of these conditions are false, but the current thread is in 500 * a nested critical section, then we have to defer the preemption 501 * until we exit the critical section. Otherwise, switch immediately 502 * to the new thread. 503 */ 504 ctd = curthread; 505 pri = td->td_priority; 506 cpri = ctd->td_priority; 507 if (pri >= cpri || cold /* || dumping */ || TD_IS_INHIBITED(ctd) || 508 td->td_kse->ke_state != KES_THREAD) 509 return (0); 510#ifndef FULL_PREEMPTION 511 if (!(pri >= PRI_MIN_ITHD && pri <= PRI_MAX_ITHD) && 512 !(cpri >= PRI_MIN_IDLE)) 513 return (0); 514#endif 515 if (ctd->td_critnest > 1) { 516 CTR1(KTR_PROC, "maybe_preempt: in critical section %d", 517 ctd->td_critnest); 518 ctd->td_flags |= TDF_OWEPREEMPT; 519 return (0); 520 } 521 522 /* 523 * Our thread state says that we are already on a run queue, so 524 * update our state as if we had been dequeued by choosethread(). 525 */ 526 MPASS(TD_ON_RUNQ(td)); 527 TD_SET_RUNNING(td); 528 CTR3(KTR_PROC, "preempting to thread %p (pid %d, %s)\n", td, 529 td->td_proc->p_pid, td->td_proc->p_comm); 530 mi_switch(SW_INVOL, td); 531 return (1); 532#else 533 return (0); 534#endif 535} 536 537#ifndef PREEMPTION 538/* XXX: There should be a non-static version of this. */ 539static void 540printf_caddr_t(void *data) 541{ 542 printf("%s", (char *)data); 543} 544static char preempt_warning[] = 545 "WARNING: Kernel preemption is disabled, expect reduced performance.\n"; 546SYSINIT(preempt_warning, SI_SUB_COPYRIGHT, SI_ORDER_ANY, printf_caddr_t, 547 preempt_warning) 548#endif 549 550/************************************************************************ 551 * SYSTEM RUN QUEUE manipulations and tests * 552 ************************************************************************/ 553/* 554 * Initialize a run structure. 555 */ 556void 557runq_init(struct runq *rq) 558{ 559 int i; 560 561 bzero(rq, sizeof *rq); 562 for (i = 0; i < RQ_NQS; i++) 563 TAILQ_INIT(&rq->rq_queues[i]); 564} 565 566/* 567 * Clear the status bit of the queue corresponding to priority level pri, 568 * indicating that it is empty. 569 */ 570static __inline void 571runq_clrbit(struct runq *rq, int pri) 572{ 573 struct rqbits *rqb; 574 575 rqb = &rq->rq_status; 576 CTR4(KTR_RUNQ, "runq_clrbit: bits=%#x %#x bit=%#x word=%d", 577 rqb->rqb_bits[RQB_WORD(pri)], 578 rqb->rqb_bits[RQB_WORD(pri)] & ~RQB_BIT(pri), 579 RQB_BIT(pri), RQB_WORD(pri)); 580 rqb->rqb_bits[RQB_WORD(pri)] &= ~RQB_BIT(pri); 581} 582 583/* 584 * Find the index of the first non-empty run queue. This is done by 585 * scanning the status bits, a set bit indicates a non-empty queue. 586 */ 587static __inline int 588runq_findbit(struct runq *rq) 589{ 590 struct rqbits *rqb; 591 int pri; 592 int i; 593 594 rqb = &rq->rq_status; 595 for (i = 0; i < RQB_LEN; i++) 596 if (rqb->rqb_bits[i]) { 597 pri = RQB_FFS(rqb->rqb_bits[i]) + (i << RQB_L2BPW); 598 CTR3(KTR_RUNQ, "runq_findbit: bits=%#x i=%d pri=%d", 599 rqb->rqb_bits[i], i, pri); 600 return (pri); 601 } 602 603 return (-1); 604} 605 606/* 607 * Set the status bit of the queue corresponding to priority level pri, 608 * indicating that it is non-empty. 609 */ 610static __inline void 611runq_setbit(struct runq *rq, int pri) 612{ 613 struct rqbits *rqb; 614 615 rqb = &rq->rq_status; 616 CTR4(KTR_RUNQ, "runq_setbit: bits=%#x %#x bit=%#x word=%d", 617 rqb->rqb_bits[RQB_WORD(pri)], 618 rqb->rqb_bits[RQB_WORD(pri)] | RQB_BIT(pri), 619 RQB_BIT(pri), RQB_WORD(pri)); 620 rqb->rqb_bits[RQB_WORD(pri)] |= RQB_BIT(pri); 621} 622 623/* 624 * Add the KSE to the queue specified by its priority, and set the 625 * corresponding status bit. 626 */ 627void 628runq_add(struct runq *rq, struct kse *ke) 629{ 630 struct rqhead *rqh; 631 int pri; 632 633 pri = ke->ke_thread->td_priority / RQ_PPQ; 634 ke->ke_rqindex = pri; 635 runq_setbit(rq, pri); 636 rqh = &rq->rq_queues[pri]; 637 CTR4(KTR_RUNQ, "runq_add: p=%p pri=%d %d rqh=%p", 638 ke->ke_proc, ke->ke_thread->td_priority, pri, rqh); 639 TAILQ_INSERT_TAIL(rqh, ke, ke_procq); 640} 641 642/* 643 * Return true if there are runnable processes of any priority on the run 644 * queue, false otherwise. Has no side effects, does not modify the run 645 * queue structure. 646 */ 647int 648runq_check(struct runq *rq) 649{ 650 struct rqbits *rqb; 651 int i; 652 653 rqb = &rq->rq_status; 654 for (i = 0; i < RQB_LEN; i++) 655 if (rqb->rqb_bits[i]) { 656 CTR2(KTR_RUNQ, "runq_check: bits=%#x i=%d", 657 rqb->rqb_bits[i], i); 658 return (1); 659 } 660 CTR0(KTR_RUNQ, "runq_check: empty"); 661 662 return (0); 663} 664 665/* 666 * Find the highest priority process on the run queue. 667 */ 668struct kse * 669runq_choose(struct runq *rq) 670{ 671 struct rqhead *rqh; 672 struct kse *ke; 673 int pri; 674 675 mtx_assert(&sched_lock, MA_OWNED); 676 while ((pri = runq_findbit(rq)) != -1) { 677 rqh = &rq->rq_queues[pri]; 678 ke = TAILQ_FIRST(rqh); 679 KASSERT(ke != NULL, ("runq_choose: no proc on busy queue")); 680 CTR3(KTR_RUNQ, 681 "runq_choose: pri=%d kse=%p rqh=%p", pri, ke, rqh); 682 return (ke); 683 } 684 CTR1(KTR_RUNQ, "runq_choose: idleproc pri=%d", pri); 685 686 return (NULL); 687} 688 689/* 690 * Remove the KSE from the queue specified by its priority, and clear the 691 * corresponding status bit if the queue becomes empty. 692 * Caller must set ke->ke_state afterwards. 693 */ 694void 695runq_remove(struct runq *rq, struct kse *ke) 696{ 697 struct rqhead *rqh; 698 int pri; 699 700 KASSERT(ke->ke_proc->p_sflag & PS_INMEM, 701 ("runq_remove: process swapped out")); 702 pri = ke->ke_rqindex; 703 rqh = &rq->rq_queues[pri]; 704 CTR4(KTR_RUNQ, "runq_remove: p=%p pri=%d %d rqh=%p", 705 ke, ke->ke_thread->td_priority, pri, rqh); 706 KASSERT(ke != NULL, ("runq_remove: no proc on busy queue")); 707 TAILQ_REMOVE(rqh, ke, ke_procq); 708 if (TAILQ_EMPTY(rqh)) { 709 CTR0(KTR_RUNQ, "runq_remove: empty"); 710 runq_clrbit(rq, pri); 711 } 712} 713 714#if 0 715void 716panc(char *string1, char *string2) 717{ 718 printf("%s", string1); 719 kdb_enter(string2); 720} 721 722void 723thread_sanity_check(struct thread *td, char *string) 724{ 725 struct proc *p; 726 struct ksegrp *kg; 727 struct kse *ke; 728 struct thread *td2 = NULL; 729 unsigned int prevpri; 730 int saw_lastassigned = 0; 731 int unassigned = 0; 732 int assigned = 0; 733 734 p = td->td_proc; 735 kg = td->td_ksegrp; 736 ke = td->td_kse; 737 738 739 if (ke) { 740 if (p != ke->ke_proc) { 741 panc(string, "wrong proc"); 742 } 743 if (ke->ke_thread != td) { 744 panc(string, "wrong thread"); 745 } 746 } 747 748 if ((p->p_flag & P_SA) == 0) { 749 if (ke == NULL) { 750 panc(string, "non KSE thread lost kse"); 751 } 752 } else { 753 prevpri = 0; 754 saw_lastassigned = 0; 755 unassigned = 0; 756 assigned = 0; 757 TAILQ_FOREACH(td2, &kg->kg_runq, td_runq) { 758 if (td2->td_priority < prevpri) { 759 panc(string, "thread runqueue unosorted"); 760 } 761 if ((td2->td_state == TDS_RUNQ) && 762 td2->td_kse && 763 (td2->td_kse->ke_state != KES_ONRUNQ)) { 764 panc(string, "KSE wrong state"); 765 } 766 prevpri = td2->td_priority; 767 if (td2->td_kse) { 768 assigned++; 769 if (unassigned) { 770 panc(string, "unassigned before assigned"); 771 } 772 if (kg->kg_last_assigned == NULL) { 773 panc(string, "lastassigned corrupt"); 774 } 775 if (saw_lastassigned) { 776 panc(string, "last assigned not last"); 777 } 778 if (td2->td_kse->ke_thread != td2) { 779 panc(string, "mismatched kse/thread"); 780 } 781 } else { 782 unassigned++; 783 } 784 if (td2 == kg->kg_last_assigned) { 785 saw_lastassigned = 1; 786 if (td2->td_kse == NULL) { 787 panc(string, "last assigned not assigned"); 788 } 789 } 790 } 791 if (kg->kg_last_assigned && (saw_lastassigned == 0)) { 792 panc(string, "where on earth does lastassigned point?"); 793 } 794#if 0 795 FOREACH_THREAD_IN_GROUP(kg, td2) { 796 if (((td2->td_flags & TDF_UNBOUND) == 0) && 797 (TD_ON_RUNQ(td2))) { 798 assigned++; 799 if (td2->td_kse == NULL) { 800 panc(string, "BOUND thread with no KSE"); 801 } 802 } 803 } 804#endif 805#if 0 806 if ((unassigned + assigned) != kg->kg_runnable) { 807 panc(string, "wrong number in runnable"); 808 } 809#endif 810 } 811 if (assigned == 12345) { 812 printf("%p %p %p %p %p %d, %d", 813 td, td2, ke, kg, p, assigned, saw_lastassigned); 814 } 815} 816#endif 817 818