subr_sleepqueue.c revision 367457
1/*- 2 * Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org> 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26/* 27 * Implementation of sleep queues used to hold queue of threads blocked on 28 * a wait channel. Sleep queues are different from turnstiles in that wait 29 * channels are not owned by anyone, so there is no priority propagation. 30 * Sleep queues can also provide a timeout and can also be interrupted by 31 * signals. That said, there are several similarities between the turnstile 32 * and sleep queue implementations. (Note: turnstiles were implemented 33 * first.) For example, both use a hash table of the same size where each 34 * bucket is referred to as a "chain" that contains both a spin lock and 35 * a linked list of queues. An individual queue is located by using a hash 36 * to pick a chain, locking the chain, and then walking the chain searching 37 * for the queue. This means that a wait channel object does not need to 38 * embed its queue head just as locks do not embed their turnstile queue 39 * head. Threads also carry around a sleep queue that they lend to the 40 * wait channel when blocking. Just as in turnstiles, the queue includes 41 * a free list of the sleep queues of other threads blocked on the same 42 * wait channel in the case of multiple waiters. 43 * 44 * Some additional functionality provided by sleep queues include the 45 * ability to set a timeout. The timeout is managed using a per-thread 46 * callout that resumes a thread if it is asleep. A thread may also 47 * catch signals while it is asleep (aka an interruptible sleep). The 48 * signal code uses sleepq_abort() to interrupt a sleeping thread. Finally, 49 * sleep queues also provide some extra assertions. One is not allowed to 50 * mix the sleep/wakeup and cv APIs for a given wait channel. Also, one 51 * must consistently use the same lock to synchronize with a wait channel, 52 * though this check is currently only a warning for sleep/wakeup due to 53 * pre-existing abuse of that API. The same lock must also be held when 54 * awakening threads, though that is currently only enforced for condition 55 * variables. 56 */ 57 58#include <sys/cdefs.h> 59__FBSDID("$FreeBSD: stable/11/sys/kern/subr_sleepqueue.c 367457 2020-11-07 18:10:59Z dim $"); 60 61#include "opt_sleepqueue_profiling.h" 62#include "opt_ddb.h" 63#include "opt_sched.h" 64#include "opt_stack.h" 65 66#include <sys/param.h> 67#include <sys/systm.h> 68#include <sys/lock.h> 69#include <sys/kernel.h> 70#include <sys/ktr.h> 71#include <sys/mutex.h> 72#include <sys/proc.h> 73#include <sys/sbuf.h> 74#include <sys/sched.h> 75#include <sys/sdt.h> 76#include <sys/signalvar.h> 77#include <sys/sleepqueue.h> 78#include <sys/stack.h> 79#include <sys/sysctl.h> 80#include <sys/time.h> 81 82#include <machine/atomic.h> 83 84#include <vm/uma.h> 85 86#ifdef DDB 87#include <ddb/ddb.h> 88#endif 89 90 91/* 92 * Constants for the hash table of sleep queue chains. 93 * SC_TABLESIZE must be a power of two for SC_MASK to work properly. 94 */ 95#define SC_TABLESIZE 256 /* Must be power of 2. */ 96#define SC_MASK (SC_TABLESIZE - 1) 97#define SC_SHIFT 8 98#define SC_HASH(wc) ((((uintptr_t)(wc) >> SC_SHIFT) ^ (uintptr_t)(wc)) & \ 99 SC_MASK) 100#define SC_LOOKUP(wc) &sleepq_chains[SC_HASH(wc)] 101#define NR_SLEEPQS 2 102/* 103 * There are two different lists of sleep queues. Both lists are connected 104 * via the sq_hash entries. The first list is the sleep queue chain list 105 * that a sleep queue is on when it is attached to a wait channel. The 106 * second list is the free list hung off of a sleep queue that is attached 107 * to a wait channel. 108 * 109 * Each sleep queue also contains the wait channel it is attached to, the 110 * list of threads blocked on that wait channel, flags specific to the 111 * wait channel, and the lock used to synchronize with a wait channel. 112 * The flags are used to catch mismatches between the various consumers 113 * of the sleep queue API (e.g. sleep/wakeup and condition variables). 114 * The lock pointer is only used when invariants are enabled for various 115 * debugging checks. 116 * 117 * Locking key: 118 * c - sleep queue chain lock 119 */ 120struct sleepqueue { 121 struct threadqueue sq_blocked[NR_SLEEPQS]; /* (c) Blocked threads. */ 122 u_int sq_blockedcnt[NR_SLEEPQS]; /* (c) N. of blocked threads. */ 123 LIST_ENTRY(sleepqueue) sq_hash; /* (c) Chain and free list. */ 124 LIST_HEAD(, sleepqueue) sq_free; /* (c) Free queues. */ 125 void *sq_wchan; /* (c) Wait channel. */ 126 int sq_type; /* (c) Queue type. */ 127#ifdef INVARIANTS 128 struct lock_object *sq_lock; /* (c) Associated lock. */ 129#endif 130}; 131 132struct sleepqueue_chain { 133 LIST_HEAD(, sleepqueue) sc_queues; /* List of sleep queues. */ 134 struct mtx sc_lock; /* Spin lock for this chain. */ 135#ifdef SLEEPQUEUE_PROFILING 136 u_int sc_depth; /* Length of sc_queues. */ 137 u_int sc_max_depth; /* Max length of sc_queues. */ 138#endif 139}; 140 141#ifdef SLEEPQUEUE_PROFILING 142u_int sleepq_max_depth; 143static SYSCTL_NODE(_debug, OID_AUTO, sleepq, CTLFLAG_RD, 0, "sleepq profiling"); 144static SYSCTL_NODE(_debug_sleepq, OID_AUTO, chains, CTLFLAG_RD, 0, 145 "sleepq chain stats"); 146SYSCTL_UINT(_debug_sleepq, OID_AUTO, max_depth, CTLFLAG_RD, &sleepq_max_depth, 147 0, "maxmimum depth achieved of a single chain"); 148 149static void sleepq_profile(const char *wmesg); 150static int prof_enabled; 151#endif 152static struct sleepqueue_chain sleepq_chains[SC_TABLESIZE]; 153static uma_zone_t sleepq_zone; 154 155/* 156 * Prototypes for non-exported routines. 157 */ 158static int sleepq_catch_signals(void *wchan, int pri); 159static int sleepq_check_signals(void); 160static int sleepq_check_timeout(void); 161#ifdef INVARIANTS 162static void sleepq_dtor(void *mem, int size, void *arg); 163#endif 164static int sleepq_init(void *mem, int size, int flags); 165static int sleepq_resume_thread(struct sleepqueue *sq, struct thread *td, 166 int pri); 167static void sleepq_switch(void *wchan, int pri); 168static void sleepq_timeout(void *arg); 169 170SDT_PROBE_DECLARE(sched, , , sleep); 171SDT_PROBE_DECLARE(sched, , , wakeup); 172 173/* 174 * Initialize SLEEPQUEUE_PROFILING specific sysctl nodes. 175 * Note that it must happen after sleepinit() has been fully executed, so 176 * it must happen after SI_SUB_KMEM SYSINIT() subsystem setup. 177 */ 178#ifdef SLEEPQUEUE_PROFILING 179static void 180init_sleepqueue_profiling(void) 181{ 182 char chain_name[10]; 183 struct sysctl_oid *chain_oid; 184 u_int i; 185 186 for (i = 0; i < SC_TABLESIZE; i++) { 187 snprintf(chain_name, sizeof(chain_name), "%u", i); 188 chain_oid = SYSCTL_ADD_NODE(NULL, 189 SYSCTL_STATIC_CHILDREN(_debug_sleepq_chains), OID_AUTO, 190 chain_name, CTLFLAG_RD, NULL, "sleepq chain stats"); 191 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO, 192 "depth", CTLFLAG_RD, &sleepq_chains[i].sc_depth, 0, NULL); 193 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO, 194 "max_depth", CTLFLAG_RD, &sleepq_chains[i].sc_max_depth, 0, 195 NULL); 196 } 197} 198 199SYSINIT(sleepqueue_profiling, SI_SUB_LOCK, SI_ORDER_ANY, 200 init_sleepqueue_profiling, NULL); 201#endif 202 203/* 204 * Early initialization of sleep queues that is called from the sleepinit() 205 * SYSINIT. 206 */ 207void 208init_sleepqueues(void) 209{ 210 int i; 211 212 for (i = 0; i < SC_TABLESIZE; i++) { 213 LIST_INIT(&sleepq_chains[i].sc_queues); 214 mtx_init(&sleepq_chains[i].sc_lock, "sleepq chain", NULL, 215 MTX_SPIN | MTX_RECURSE); 216 } 217 sleepq_zone = uma_zcreate("SLEEPQUEUE", sizeof(struct sleepqueue), 218#ifdef INVARIANTS 219 NULL, sleepq_dtor, sleepq_init, NULL, UMA_ALIGN_CACHE, 0); 220#else 221 NULL, NULL, sleepq_init, NULL, UMA_ALIGN_CACHE, 0); 222#endif 223 224 thread0.td_sleepqueue = sleepq_alloc(); 225} 226 227/* 228 * Get a sleep queue for a new thread. 229 */ 230struct sleepqueue * 231sleepq_alloc(void) 232{ 233 234 return (uma_zalloc(sleepq_zone, M_WAITOK)); 235} 236 237/* 238 * Free a sleep queue when a thread is destroyed. 239 */ 240void 241sleepq_free(struct sleepqueue *sq) 242{ 243 244 uma_zfree(sleepq_zone, sq); 245} 246 247/* 248 * Lock the sleep queue chain associated with the specified wait channel. 249 */ 250void 251sleepq_lock(void *wchan) 252{ 253 struct sleepqueue_chain *sc; 254 255 sc = SC_LOOKUP(wchan); 256 mtx_lock_spin(&sc->sc_lock); 257} 258 259/* 260 * Look up the sleep queue associated with a given wait channel in the hash 261 * table locking the associated sleep queue chain. If no queue is found in 262 * the table, NULL is returned. 263 */ 264struct sleepqueue * 265sleepq_lookup(void *wchan) 266{ 267 struct sleepqueue_chain *sc; 268 struct sleepqueue *sq; 269 270 KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); 271 sc = SC_LOOKUP(wchan); 272 mtx_assert(&sc->sc_lock, MA_OWNED); 273 LIST_FOREACH(sq, &sc->sc_queues, sq_hash) 274 if (sq->sq_wchan == wchan) 275 return (sq); 276 return (NULL); 277} 278 279/* 280 * Unlock the sleep queue chain associated with a given wait channel. 281 */ 282void 283sleepq_release(void *wchan) 284{ 285 struct sleepqueue_chain *sc; 286 287 sc = SC_LOOKUP(wchan); 288 mtx_unlock_spin(&sc->sc_lock); 289} 290 291/* 292 * Places the current thread on the sleep queue for the specified wait 293 * channel. If INVARIANTS is enabled, then it associates the passed in 294 * lock with the sleepq to make sure it is held when that sleep queue is 295 * woken up. 296 */ 297void 298sleepq_add(void *wchan, struct lock_object *lock, const char *wmesg, int flags, 299 int queue) 300{ 301 struct sleepqueue_chain *sc; 302 struct sleepqueue *sq; 303 struct thread *td; 304 305 td = curthread; 306 sc = SC_LOOKUP(wchan); 307 mtx_assert(&sc->sc_lock, MA_OWNED); 308 MPASS(td->td_sleepqueue != NULL); 309 MPASS(wchan != NULL); 310 MPASS((queue >= 0) && (queue < NR_SLEEPQS)); 311 312 /* If this thread is not allowed to sleep, die a horrible death. */ 313 KASSERT(td->td_no_sleeping == 0, 314 ("%s: td %p to sleep on wchan %p with sleeping prohibited", 315 __func__, td, wchan)); 316 317 /* Look up the sleep queue associated with the wait channel 'wchan'. */ 318 sq = sleepq_lookup(wchan); 319 320 /* 321 * If the wait channel does not already have a sleep queue, use 322 * this thread's sleep queue. Otherwise, insert the current thread 323 * into the sleep queue already in use by this wait channel. 324 */ 325 if (sq == NULL) { 326#ifdef INVARIANTS 327 int i; 328 329 sq = td->td_sleepqueue; 330 for (i = 0; i < NR_SLEEPQS; i++) { 331 KASSERT(TAILQ_EMPTY(&sq->sq_blocked[i]), 332 ("thread's sleep queue %d is not empty", i)); 333 KASSERT(sq->sq_blockedcnt[i] == 0, 334 ("thread's sleep queue %d count mismatches", i)); 335 } 336 KASSERT(LIST_EMPTY(&sq->sq_free), 337 ("thread's sleep queue has a non-empty free list")); 338 KASSERT(sq->sq_wchan == NULL, ("stale sq_wchan pointer")); 339 sq->sq_lock = lock; 340#endif 341#ifdef SLEEPQUEUE_PROFILING 342 sc->sc_depth++; 343 if (sc->sc_depth > sc->sc_max_depth) { 344 sc->sc_max_depth = sc->sc_depth; 345 if (sc->sc_max_depth > sleepq_max_depth) 346 sleepq_max_depth = sc->sc_max_depth; 347 } 348#endif 349 sq = td->td_sleepqueue; 350 LIST_INSERT_HEAD(&sc->sc_queues, sq, sq_hash); 351 sq->sq_wchan = wchan; 352 sq->sq_type = flags & SLEEPQ_TYPE; 353 } else { 354 MPASS(wchan == sq->sq_wchan); 355 MPASS(lock == sq->sq_lock); 356 MPASS((flags & SLEEPQ_TYPE) == sq->sq_type); 357 LIST_INSERT_HEAD(&sq->sq_free, td->td_sleepqueue, sq_hash); 358 } 359 thread_lock(td); 360 TAILQ_INSERT_TAIL(&sq->sq_blocked[queue], td, td_slpq); 361 sq->sq_blockedcnt[queue]++; 362 td->td_sleepqueue = NULL; 363 td->td_sqqueue = queue; 364 td->td_wchan = wchan; 365 td->td_wmesg = wmesg; 366 if (flags & SLEEPQ_INTERRUPTIBLE) { 367 td->td_flags |= TDF_SINTR; 368 td->td_flags &= ~TDF_SLEEPABORT; 369 } 370 thread_unlock(td); 371} 372 373/* 374 * Sets a timeout that will remove the current thread from the specified 375 * sleep queue after timo ticks if the thread has not already been awakened. 376 */ 377void 378sleepq_set_timeout_sbt(void *wchan, sbintime_t sbt, sbintime_t pr, 379 int flags) 380{ 381 struct sleepqueue_chain *sc; 382 struct thread *td; 383 sbintime_t pr1; 384 385 td = curthread; 386 sc = SC_LOOKUP(wchan); 387 mtx_assert(&sc->sc_lock, MA_OWNED); 388 MPASS(TD_ON_SLEEPQ(td)); 389 MPASS(td->td_sleepqueue == NULL); 390 MPASS(wchan != NULL); 391 if (cold && td == &thread0) 392 panic("timed sleep before timers are working"); 393 KASSERT(td->td_sleeptimo == 0, ("td %d %p td_sleeptimo %jx", 394 td->td_tid, td, (uintmax_t)td->td_sleeptimo)); 395 thread_lock(td); 396 callout_when(sbt, pr, flags, &td->td_sleeptimo, &pr1); 397 thread_unlock(td); 398 callout_reset_sbt_on(&td->td_slpcallout, td->td_sleeptimo, pr1, 399 sleepq_timeout, td, PCPU_GET(cpuid), flags | C_PRECALC | 400 C_DIRECT_EXEC); 401} 402 403/* 404 * Return the number of actual sleepers for the specified queue. 405 */ 406u_int 407sleepq_sleepcnt(void *wchan, int queue) 408{ 409 struct sleepqueue *sq; 410 411 KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); 412 MPASS((queue >= 0) && (queue < NR_SLEEPQS)); 413 sq = sleepq_lookup(wchan); 414 if (sq == NULL) 415 return (0); 416 return (sq->sq_blockedcnt[queue]); 417} 418 419/* 420 * Marks the pending sleep of the current thread as interruptible and 421 * makes an initial check for pending signals before putting a thread 422 * to sleep. Enters and exits with the thread lock held. Thread lock 423 * may have transitioned from the sleepq lock to a run lock. 424 */ 425static int 426sleepq_catch_signals(void *wchan, int pri) 427{ 428 struct sleepqueue_chain *sc; 429 struct sleepqueue *sq; 430 struct thread *td; 431 struct proc *p; 432 struct sigacts *ps; 433 int sig, ret; 434 435 ret = 0; 436 td = curthread; 437 p = curproc; 438 sc = SC_LOOKUP(wchan); 439 mtx_assert(&sc->sc_lock, MA_OWNED); 440 MPASS(wchan != NULL); 441 if ((td->td_pflags & TDP_WAKEUP) != 0) { 442 td->td_pflags &= ~TDP_WAKEUP; 443 ret = EINTR; 444 thread_lock(td); 445 goto out; 446 } 447 448 /* 449 * See if there are any pending signals or suspension requests for this 450 * thread. If not, we can switch immediately. 451 */ 452 thread_lock(td); 453 if ((td->td_flags & (TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK)) != 0) { 454 thread_unlock(td); 455 mtx_unlock_spin(&sc->sc_lock); 456 CTR3(KTR_PROC, "sleepq catching signals: thread %p (pid %ld, %s)", 457 (void *)td, (long)p->p_pid, td->td_name); 458 PROC_LOCK(p); 459 /* 460 * Check for suspension first. Checking for signals and then 461 * suspending could result in a missed signal, since a signal 462 * can be delivered while this thread is suspended. 463 */ 464 if ((td->td_flags & TDF_NEEDSUSPCHK) != 0) { 465 ret = thread_suspend_check(1); 466 MPASS(ret == 0 || ret == EINTR || ret == ERESTART); 467 if (ret != 0) { 468 PROC_UNLOCK(p); 469 mtx_lock_spin(&sc->sc_lock); 470 thread_lock(td); 471 goto out; 472 } 473 } 474 if ((td->td_flags & TDF_NEEDSIGCHK) != 0) { 475 ps = p->p_sigacts; 476 mtx_lock(&ps->ps_mtx); 477 sig = cursig(td); 478 if (sig == -1) { 479 mtx_unlock(&ps->ps_mtx); 480 KASSERT((td->td_flags & TDF_SBDRY) != 0, 481 ("lost TDF_SBDRY")); 482 KASSERT(TD_SBDRY_INTR(td), 483 ("lost TDF_SERESTART of TDF_SEINTR")); 484 KASSERT((td->td_flags & 485 (TDF_SEINTR | TDF_SERESTART)) != 486 (TDF_SEINTR | TDF_SERESTART), 487 ("both TDF_SEINTR and TDF_SERESTART")); 488 ret = TD_SBDRY_ERRNO(td); 489 } else if (sig != 0) { 490 ret = SIGISMEMBER(ps->ps_sigintr, sig) ? 491 EINTR : ERESTART; 492 mtx_unlock(&ps->ps_mtx); 493 } else { 494 mtx_unlock(&ps->ps_mtx); 495 } 496 497 /* 498 * Do not go into sleep if this thread was the 499 * ptrace(2) attach leader. cursig() consumed 500 * SIGSTOP from PT_ATTACH, but we usually act 501 * on the signal by interrupting sleep, and 502 * should do that here as well. 503 */ 504 if ((td->td_dbgflags & TDB_FSTP) != 0) { 505 if (ret == 0) 506 ret = EINTR; 507 td->td_dbgflags &= ~TDB_FSTP; 508 } 509 } 510 /* 511 * Lock the per-process spinlock prior to dropping the PROC_LOCK 512 * to avoid a signal delivery race. PROC_LOCK, PROC_SLOCK, and 513 * thread_lock() are currently held in tdsendsignal(). 514 */ 515 PROC_SLOCK(p); 516 mtx_lock_spin(&sc->sc_lock); 517 PROC_UNLOCK(p); 518 thread_lock(td); 519 PROC_SUNLOCK(p); 520 } 521 if (ret == 0) { 522 sleepq_switch(wchan, pri); 523 return (0); 524 } 525out: 526 /* 527 * There were pending signals and this thread is still 528 * on the sleep queue, remove it from the sleep queue. 529 */ 530 if (TD_ON_SLEEPQ(td)) { 531 sq = sleepq_lookup(wchan); 532 if (sleepq_resume_thread(sq, td, 0)) { 533#ifdef INVARIANTS 534 /* 535 * This thread hasn't gone to sleep yet, so it 536 * should not be swapped out. 537 */ 538 panic("not waking up swapper"); 539#endif 540 } 541 } 542 mtx_unlock_spin(&sc->sc_lock); 543 MPASS(td->td_lock != &sc->sc_lock); 544 return (ret); 545} 546 547/* 548 * Switches to another thread if we are still asleep on a sleep queue. 549 * Returns with thread lock. 550 */ 551static void 552sleepq_switch(void *wchan, int pri) 553{ 554 struct sleepqueue_chain *sc; 555 struct sleepqueue *sq; 556 struct thread *td; 557 bool rtc_changed; 558 559 td = curthread; 560 sc = SC_LOOKUP(wchan); 561 mtx_assert(&sc->sc_lock, MA_OWNED); 562 THREAD_LOCK_ASSERT(td, MA_OWNED); 563 564 /* 565 * If we have a sleep queue, then we've already been woken up, so 566 * just return. 567 */ 568 if (td->td_sleepqueue != NULL) { 569 mtx_unlock_spin(&sc->sc_lock); 570 return; 571 } 572 573 /* 574 * If TDF_TIMEOUT is set, then our sleep has been timed out 575 * already but we are still on the sleep queue, so dequeue the 576 * thread and return. 577 * 578 * Do the same if the real-time clock has been adjusted since this 579 * thread calculated its timeout based on that clock. This handles 580 * the following race: 581 * - The Ts thread needs to sleep until an absolute real-clock time. 582 * It copies the global rtc_generation into curthread->td_rtcgen, 583 * reads the RTC, and calculates a sleep duration based on that time. 584 * See umtxq_sleep() for an example. 585 * - The Tc thread adjusts the RTC, bumps rtc_generation, and wakes 586 * threads that are sleeping until an absolute real-clock time. 587 * See tc_setclock() and the POSIX specification of clock_settime(). 588 * - Ts reaches the code below. It holds the sleepqueue chain lock, 589 * so Tc has finished waking, so this thread must test td_rtcgen. 590 * (The declaration of td_rtcgen refers to this comment.) 591 */ 592 rtc_changed = td->td_rtcgen != 0 && td->td_rtcgen != rtc_generation; 593 if ((td->td_flags & TDF_TIMEOUT) || rtc_changed) { 594 if (rtc_changed) { 595 td->td_rtcgen = 0; 596 } 597 MPASS(TD_ON_SLEEPQ(td)); 598 sq = sleepq_lookup(wchan); 599 if (sleepq_resume_thread(sq, td, 0)) { 600#ifdef INVARIANTS 601 /* 602 * This thread hasn't gone to sleep yet, so it 603 * should not be swapped out. 604 */ 605 panic("not waking up swapper"); 606#endif 607 } 608 mtx_unlock_spin(&sc->sc_lock); 609 return; 610 } 611#ifdef SLEEPQUEUE_PROFILING 612 if (prof_enabled) 613 sleepq_profile(td->td_wmesg); 614#endif 615 MPASS(td->td_sleepqueue == NULL); 616 sched_sleep(td, pri); 617 thread_lock_set(td, &sc->sc_lock); 618 SDT_PROBE0(sched, , , sleep); 619 TD_SET_SLEEPING(td); 620 mi_switch(SW_VOL | SWT_SLEEPQ, NULL); 621 KASSERT(TD_IS_RUNNING(td), ("running but not TDS_RUNNING")); 622 CTR3(KTR_PROC, "sleepq resume: thread %p (pid %ld, %s)", 623 (void *)td, (long)td->td_proc->p_pid, (void *)td->td_name); 624} 625 626/* 627 * Check to see if we timed out. 628 */ 629static int 630sleepq_check_timeout(void) 631{ 632 struct thread *td; 633 int res; 634 635 td = curthread; 636 THREAD_LOCK_ASSERT(td, MA_OWNED); 637 638 /* 639 * If TDF_TIMEOUT is set, we timed out. But recheck 640 * td_sleeptimo anyway. 641 */ 642 res = 0; 643 if (td->td_sleeptimo != 0) { 644 if (td->td_sleeptimo <= sbinuptime()) 645 res = EWOULDBLOCK; 646 td->td_sleeptimo = 0; 647 } 648 if (td->td_flags & TDF_TIMEOUT) 649 td->td_flags &= ~TDF_TIMEOUT; 650 else 651 /* 652 * We ignore the situation where timeout subsystem was 653 * unable to stop our callout. The struct thread is 654 * type-stable, the callout will use the correct 655 * memory when running. The checks of the 656 * td_sleeptimo value in this function and in 657 * sleepq_timeout() ensure that the thread does not 658 * get spurious wakeups, even if the callout was reset 659 * or thread reused. 660 */ 661 callout_stop(&td->td_slpcallout); 662 return (res); 663} 664 665/* 666 * Check to see if we were awoken by a signal. 667 */ 668static int 669sleepq_check_signals(void) 670{ 671 struct thread *td; 672 673 td = curthread; 674 THREAD_LOCK_ASSERT(td, MA_OWNED); 675 676 /* We are no longer in an interruptible sleep. */ 677 if (td->td_flags & TDF_SINTR) 678 td->td_flags &= ~TDF_SINTR; 679 680 if (td->td_flags & TDF_SLEEPABORT) { 681 td->td_flags &= ~TDF_SLEEPABORT; 682 return (td->td_intrval); 683 } 684 685 return (0); 686} 687 688/* 689 * Block the current thread until it is awakened from its sleep queue. 690 */ 691void 692sleepq_wait(void *wchan, int pri) 693{ 694 struct thread *td; 695 696 td = curthread; 697 MPASS(!(td->td_flags & TDF_SINTR)); 698 thread_lock(td); 699 sleepq_switch(wchan, pri); 700 thread_unlock(td); 701} 702 703/* 704 * Block the current thread until it is awakened from its sleep queue 705 * or it is interrupted by a signal. 706 */ 707int 708sleepq_wait_sig(void *wchan, int pri) 709{ 710 int rcatch; 711 int rval; 712 713 rcatch = sleepq_catch_signals(wchan, pri); 714 rval = sleepq_check_signals(); 715 thread_unlock(curthread); 716 if (rcatch) 717 return (rcatch); 718 return (rval); 719} 720 721/* 722 * Block the current thread until it is awakened from its sleep queue 723 * or it times out while waiting. 724 */ 725int 726sleepq_timedwait(void *wchan, int pri) 727{ 728 struct thread *td; 729 int rval; 730 731 td = curthread; 732 MPASS(!(td->td_flags & TDF_SINTR)); 733 thread_lock(td); 734 sleepq_switch(wchan, pri); 735 rval = sleepq_check_timeout(); 736 thread_unlock(td); 737 738 return (rval); 739} 740 741/* 742 * Block the current thread until it is awakened from its sleep queue, 743 * it is interrupted by a signal, or it times out waiting to be awakened. 744 */ 745int 746sleepq_timedwait_sig(void *wchan, int pri) 747{ 748 int rcatch, rvalt, rvals; 749 750 rcatch = sleepq_catch_signals(wchan, pri); 751 rvalt = sleepq_check_timeout(); 752 rvals = sleepq_check_signals(); 753 thread_unlock(curthread); 754 if (rcatch) 755 return (rcatch); 756 if (rvals) 757 return (rvals); 758 return (rvalt); 759} 760 761/* 762 * Returns the type of sleepqueue given a waitchannel. 763 */ 764int 765sleepq_type(void *wchan) 766{ 767 struct sleepqueue *sq; 768 int type; 769 770 MPASS(wchan != NULL); 771 772 sleepq_lock(wchan); 773 sq = sleepq_lookup(wchan); 774 if (sq == NULL) { 775 sleepq_release(wchan); 776 return (-1); 777 } 778 type = sq->sq_type; 779 sleepq_release(wchan); 780 return (type); 781} 782 783/* 784 * Removes a thread from a sleep queue and makes it 785 * runnable. 786 */ 787static int 788sleepq_resume_thread(struct sleepqueue *sq, struct thread *td, int pri) 789{ 790 struct sleepqueue_chain *sc; 791 792 MPASS(td != NULL); 793 MPASS(sq->sq_wchan != NULL); 794 MPASS(td->td_wchan == sq->sq_wchan); 795 MPASS(td->td_sqqueue < NR_SLEEPQS && td->td_sqqueue >= 0); 796 THREAD_LOCK_ASSERT(td, MA_OWNED); 797 sc = SC_LOOKUP(sq->sq_wchan); 798 mtx_assert(&sc->sc_lock, MA_OWNED); 799 800 SDT_PROBE2(sched, , , wakeup, td, td->td_proc); 801 802 /* Remove the thread from the queue. */ 803 sq->sq_blockedcnt[td->td_sqqueue]--; 804 TAILQ_REMOVE(&sq->sq_blocked[td->td_sqqueue], td, td_slpq); 805 806 /* 807 * Get a sleep queue for this thread. If this is the last waiter, 808 * use the queue itself and take it out of the chain, otherwise, 809 * remove a queue from the free list. 810 */ 811 if (LIST_EMPTY(&sq->sq_free)) { 812 td->td_sleepqueue = sq; 813#ifdef INVARIANTS 814 sq->sq_wchan = NULL; 815#endif 816#ifdef SLEEPQUEUE_PROFILING 817 sc->sc_depth--; 818#endif 819 } else 820 td->td_sleepqueue = LIST_FIRST(&sq->sq_free); 821 LIST_REMOVE(td->td_sleepqueue, sq_hash); 822 823 td->td_wmesg = NULL; 824 td->td_wchan = NULL; 825 td->td_flags &= ~TDF_SINTR; 826 827 CTR3(KTR_PROC, "sleepq_wakeup: thread %p (pid %ld, %s)", 828 (void *)td, (long)td->td_proc->p_pid, td->td_name); 829 830 /* Adjust priority if requested. */ 831 MPASS(pri == 0 || (pri >= PRI_MIN && pri <= PRI_MAX)); 832 if (pri != 0 && td->td_priority > pri && 833 PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 834 sched_prio(td, pri); 835 836 /* 837 * Note that thread td might not be sleeping if it is running 838 * sleepq_catch_signals() on another CPU or is blocked on its 839 * proc lock to check signals. There's no need to mark the 840 * thread runnable in that case. 841 */ 842 if (TD_IS_SLEEPING(td)) { 843 TD_CLR_SLEEPING(td); 844 return (setrunnable(td)); 845 } 846 return (0); 847} 848 849#ifdef INVARIANTS 850/* 851 * UMA zone item deallocator. 852 */ 853static void 854sleepq_dtor(void *mem, int size, void *arg) 855{ 856 struct sleepqueue *sq; 857 int i; 858 859 sq = mem; 860 for (i = 0; i < NR_SLEEPQS; i++) { 861 MPASS(TAILQ_EMPTY(&sq->sq_blocked[i])); 862 MPASS(sq->sq_blockedcnt[i] == 0); 863 } 864} 865#endif 866 867/* 868 * UMA zone item initializer. 869 */ 870static int 871sleepq_init(void *mem, int size, int flags) 872{ 873 struct sleepqueue *sq; 874 int i; 875 876 bzero(mem, size); 877 sq = mem; 878 for (i = 0; i < NR_SLEEPQS; i++) { 879 TAILQ_INIT(&sq->sq_blocked[i]); 880 sq->sq_blockedcnt[i] = 0; 881 } 882 LIST_INIT(&sq->sq_free); 883 return (0); 884} 885 886/* 887 * Find thread sleeping on a wait channel and resume it. 888 */ 889int 890sleepq_signal(void *wchan, int flags, int pri, int queue) 891{ 892 struct sleepqueue_chain *sc; 893 struct sleepqueue *sq; 894 struct threadqueue *head; 895 struct thread *td, *besttd; 896 int wakeup_swapper; 897 898 CTR2(KTR_PROC, "sleepq_signal(%p, %d)", wchan, flags); 899 KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); 900 MPASS((queue >= 0) && (queue < NR_SLEEPQS)); 901 sq = sleepq_lookup(wchan); 902 if (sq == NULL) 903 return (0); 904 KASSERT(sq->sq_type == (flags & SLEEPQ_TYPE), 905 ("%s: mismatch between sleep/wakeup and cv_*", __func__)); 906 907 head = &sq->sq_blocked[queue]; 908 if (flags & SLEEPQ_UNFAIR) { 909 /* 910 * Find the most recently sleeping thread, but try to 911 * skip threads still in process of context switch to 912 * avoid spinning on the thread lock. 913 */ 914 sc = SC_LOOKUP(wchan); 915 besttd = TAILQ_LAST_FAST(head, thread, td_slpq); 916 while (besttd->td_lock != &sc->sc_lock) { 917 td = TAILQ_PREV_FAST(besttd, head, thread, td_slpq); 918 if (td == NULL) 919 break; 920 besttd = td; 921 } 922 } else { 923 /* 924 * Find the highest priority thread on the queue. If there 925 * is a tie, use the thread that first appears in the queue 926 * as it has been sleeping the longest since threads are 927 * always added to the tail of sleep queues. 928 */ 929 besttd = td = TAILQ_FIRST(head); 930 while ((td = TAILQ_NEXT(td, td_slpq)) != NULL) { 931 if (td->td_priority < besttd->td_priority) 932 besttd = td; 933 } 934 } 935 MPASS(besttd != NULL); 936 thread_lock(besttd); 937 wakeup_swapper = sleepq_resume_thread(sq, besttd, pri); 938 thread_unlock(besttd); 939 return (wakeup_swapper); 940} 941 942static bool 943match_any(struct thread *td __unused) 944{ 945 946 return (true); 947} 948 949/* 950 * Resume all threads sleeping on a specified wait channel. 951 */ 952int 953sleepq_broadcast(void *wchan, int flags, int pri, int queue) 954{ 955 struct sleepqueue *sq; 956 957 CTR2(KTR_PROC, "sleepq_broadcast(%p, %d)", wchan, flags); 958 KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); 959 MPASS((queue >= 0) && (queue < NR_SLEEPQS)); 960 sq = sleepq_lookup(wchan); 961 if (sq == NULL) 962 return (0); 963 KASSERT(sq->sq_type == (flags & SLEEPQ_TYPE), 964 ("%s: mismatch between sleep/wakeup and cv_*", __func__)); 965 966 return (sleepq_remove_matching(sq, queue, match_any, pri)); 967} 968 969/* 970 * Resume threads on the sleep queue that match the given predicate. 971 */ 972int 973sleepq_remove_matching(struct sleepqueue *sq, int queue, 974 bool (*matches)(struct thread *), int pri) 975{ 976 struct thread *td, *tdn; 977 int wakeup_swapper; 978 979 /* 980 * The last thread will be given ownership of sq and may 981 * re-enqueue itself before sleepq_resume_thread() returns, 982 * so we must cache the "next" queue item at the beginning 983 * of the final iteration. 984 */ 985 wakeup_swapper = 0; 986 TAILQ_FOREACH_SAFE(td, &sq->sq_blocked[queue], td_slpq, tdn) { 987 thread_lock(td); 988 if (matches(td)) 989 wakeup_swapper |= sleepq_resume_thread(sq, td, pri); 990 thread_unlock(td); 991 } 992 993 return (wakeup_swapper); 994} 995 996/* 997 * Time sleeping threads out. When the timeout expires, the thread is 998 * removed from the sleep queue and made runnable if it is still asleep. 999 */ 1000static void 1001sleepq_timeout(void *arg) 1002{ 1003 struct sleepqueue_chain *sc; 1004 struct sleepqueue *sq; 1005 struct thread *td; 1006 void *wchan; 1007 int wakeup_swapper; 1008 1009 td = arg; 1010 wakeup_swapper = 0; 1011 CTR3(KTR_PROC, "sleepq_timeout: thread %p (pid %ld, %s)", 1012 (void *)td, (long)td->td_proc->p_pid, (void *)td->td_name); 1013 1014 thread_lock(td); 1015 1016 if (td->td_sleeptimo > sbinuptime() || td->td_sleeptimo == 0) { 1017 /* 1018 * The thread does not want a timeout (yet). 1019 */ 1020 } else if (TD_IS_SLEEPING(td) && TD_ON_SLEEPQ(td)) { 1021 /* 1022 * See if the thread is asleep and get the wait 1023 * channel if it is. 1024 */ 1025 wchan = td->td_wchan; 1026 sc = SC_LOOKUP(wchan); 1027 THREAD_LOCKPTR_ASSERT(td, &sc->sc_lock); 1028 sq = sleepq_lookup(wchan); 1029 MPASS(sq != NULL); 1030 td->td_flags |= TDF_TIMEOUT; 1031 wakeup_swapper = sleepq_resume_thread(sq, td, 0); 1032 } else if (TD_ON_SLEEPQ(td)) { 1033 /* 1034 * If the thread is on the SLEEPQ but isn't sleeping 1035 * yet, it can either be on another CPU in between 1036 * sleepq_add() and one of the sleepq_*wait*() 1037 * routines or it can be in sleepq_catch_signals(). 1038 */ 1039 td->td_flags |= TDF_TIMEOUT; 1040 } 1041 1042 thread_unlock(td); 1043 if (wakeup_swapper) 1044 kick_proc0(); 1045} 1046 1047/* 1048 * Resumes a specific thread from the sleep queue associated with a specific 1049 * wait channel if it is on that queue. 1050 */ 1051void 1052sleepq_remove(struct thread *td, void *wchan) 1053{ 1054 struct sleepqueue *sq; 1055 int wakeup_swapper; 1056 1057 /* 1058 * Look up the sleep queue for this wait channel, then re-check 1059 * that the thread is asleep on that channel, if it is not, then 1060 * bail. 1061 */ 1062 MPASS(wchan != NULL); 1063 sleepq_lock(wchan); 1064 sq = sleepq_lookup(wchan); 1065 /* 1066 * We can not lock the thread here as it may be sleeping on a 1067 * different sleepq. However, holding the sleepq lock for this 1068 * wchan can guarantee that we do not miss a wakeup for this 1069 * channel. The asserts below will catch any false positives. 1070 */ 1071 if (!TD_ON_SLEEPQ(td) || td->td_wchan != wchan) { 1072 sleepq_release(wchan); 1073 return; 1074 } 1075 /* Thread is asleep on sleep queue sq, so wake it up. */ 1076 thread_lock(td); 1077 MPASS(sq != NULL); 1078 MPASS(td->td_wchan == wchan); 1079 wakeup_swapper = sleepq_resume_thread(sq, td, 0); 1080 thread_unlock(td); 1081 sleepq_release(wchan); 1082 if (wakeup_swapper) 1083 kick_proc0(); 1084} 1085 1086/* 1087 * Abort a thread as if an interrupt had occurred. Only abort 1088 * interruptible waits (unfortunately it isn't safe to abort others). 1089 */ 1090int 1091sleepq_abort(struct thread *td, int intrval) 1092{ 1093 struct sleepqueue *sq; 1094 void *wchan; 1095 1096 THREAD_LOCK_ASSERT(td, MA_OWNED); 1097 MPASS(TD_ON_SLEEPQ(td)); 1098 MPASS(td->td_flags & TDF_SINTR); 1099 MPASS(intrval == EINTR || intrval == ERESTART); 1100 1101 /* 1102 * If the TDF_TIMEOUT flag is set, just leave. A 1103 * timeout is scheduled anyhow. 1104 */ 1105 if (td->td_flags & TDF_TIMEOUT) 1106 return (0); 1107 1108 CTR3(KTR_PROC, "sleepq_abort: thread %p (pid %ld, %s)", 1109 (void *)td, (long)td->td_proc->p_pid, (void *)td->td_name); 1110 td->td_intrval = intrval; 1111 td->td_flags |= TDF_SLEEPABORT; 1112 /* 1113 * If the thread has not slept yet it will find the signal in 1114 * sleepq_catch_signals() and call sleepq_resume_thread. Otherwise 1115 * we have to do it here. 1116 */ 1117 if (!TD_IS_SLEEPING(td)) 1118 return (0); 1119 wchan = td->td_wchan; 1120 MPASS(wchan != NULL); 1121 sq = sleepq_lookup(wchan); 1122 MPASS(sq != NULL); 1123 1124 /* Thread is asleep on sleep queue sq, so wake it up. */ 1125 return (sleepq_resume_thread(sq, td, 0)); 1126} 1127 1128void 1129sleepq_chains_remove_matching(bool (*matches)(struct thread *)) 1130{ 1131 struct sleepqueue_chain *sc; 1132 struct sleepqueue *sq, *sq1; 1133 int i, wakeup_swapper; 1134 1135 wakeup_swapper = 0; 1136 for (sc = &sleepq_chains[0]; sc < sleepq_chains + SC_TABLESIZE; ++sc) { 1137 if (LIST_EMPTY(&sc->sc_queues)) { 1138 continue; 1139 } 1140 mtx_lock_spin(&sc->sc_lock); 1141 LIST_FOREACH_SAFE(sq, &sc->sc_queues, sq_hash, sq1) { 1142 for (i = 0; i < NR_SLEEPQS; ++i) { 1143 wakeup_swapper |= sleepq_remove_matching(sq, i, 1144 matches, 0); 1145 } 1146 } 1147 mtx_unlock_spin(&sc->sc_lock); 1148 } 1149 if (wakeup_swapper) { 1150 kick_proc0(); 1151 } 1152} 1153 1154/* 1155 * Prints the stacks of all threads presently sleeping on wchan/queue to 1156 * the sbuf sb. Sets count_stacks_printed to the number of stacks actually 1157 * printed. Typically, this will equal the number of threads sleeping on the 1158 * queue, but may be less if sb overflowed before all stacks were printed. 1159 */ 1160#ifdef STACK 1161int 1162sleepq_sbuf_print_stacks(struct sbuf *sb, void *wchan, int queue, 1163 int *count_stacks_printed) 1164{ 1165 struct thread *td, *td_next; 1166 struct sleepqueue *sq; 1167 struct stack **st; 1168 struct sbuf **td_infos; 1169 int i, stack_idx, error, stacks_to_allocate; 1170 bool finished, partial_print; 1171 1172 error = 0; 1173 finished = false; 1174 partial_print = false; 1175 1176 KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); 1177 MPASS((queue >= 0) && (queue < NR_SLEEPQS)); 1178 1179 stacks_to_allocate = 10; 1180 for (i = 0; i < 3 && !finished ; i++) { 1181 /* We cannot malloc while holding the queue's spinlock, so 1182 * we do our mallocs now, and hope it is enough. If it 1183 * isn't, we will free these, drop the lock, malloc more, 1184 * and try again, up to a point. After that point we will 1185 * give up and report ENOMEM. We also cannot write to sb 1186 * during this time since the client may have set the 1187 * SBUF_AUTOEXTEND flag on their sbuf, which could cause a 1188 * malloc as we print to it. So we defer actually printing 1189 * to sb until after we drop the spinlock. 1190 */ 1191 1192 /* Where we will store the stacks. */ 1193 st = malloc(sizeof(struct stack *) * stacks_to_allocate, 1194 M_TEMP, M_WAITOK); 1195 for (stack_idx = 0; stack_idx < stacks_to_allocate; 1196 stack_idx++) 1197 st[stack_idx] = stack_create(); 1198 1199 /* Where we will store the td name, tid, etc. */ 1200 td_infos = malloc(sizeof(struct sbuf *) * stacks_to_allocate, 1201 M_TEMP, M_WAITOK); 1202 for (stack_idx = 0; stack_idx < stacks_to_allocate; 1203 stack_idx++) 1204 td_infos[stack_idx] = sbuf_new(NULL, NULL, 1205 MAXCOMLEN + sizeof(struct thread *) * 2 + 40, 1206 SBUF_FIXEDLEN); 1207 1208 sleepq_lock(wchan); 1209 sq = sleepq_lookup(wchan); 1210 if (sq == NULL) { 1211 /* This sleepq does not exist; exit and return ENOENT. */ 1212 error = ENOENT; 1213 finished = true; 1214 sleepq_release(wchan); 1215 goto loop_end; 1216 } 1217 1218 stack_idx = 0; 1219 /* Save thread info */ 1220 TAILQ_FOREACH_SAFE(td, &sq->sq_blocked[queue], td_slpq, 1221 td_next) { 1222 if (stack_idx >= stacks_to_allocate) 1223 goto loop_end; 1224 1225 /* Note the td_lock is equal to the sleepq_lock here. */ 1226 stack_save_td(st[stack_idx], td); 1227 1228 sbuf_printf(td_infos[stack_idx], "%d: %s %p", 1229 td->td_tid, td->td_name, td); 1230 1231 ++stack_idx; 1232 } 1233 1234 finished = true; 1235 sleepq_release(wchan); 1236 1237 /* Print the stacks */ 1238 for (i = 0; i < stack_idx; i++) { 1239 sbuf_finish(td_infos[i]); 1240 sbuf_printf(sb, "--- thread %s: ---\n", sbuf_data(td_infos[i])); 1241 stack_sbuf_print(sb, st[i]); 1242 sbuf_printf(sb, "\n"); 1243 1244 error = sbuf_error(sb); 1245 if (error == 0) 1246 *count_stacks_printed = stack_idx; 1247 } 1248 1249loop_end: 1250 if (!finished) 1251 sleepq_release(wchan); 1252 for (stack_idx = 0; stack_idx < stacks_to_allocate; 1253 stack_idx++) 1254 stack_destroy(st[stack_idx]); 1255 for (stack_idx = 0; stack_idx < stacks_to_allocate; 1256 stack_idx++) 1257 sbuf_delete(td_infos[stack_idx]); 1258 free(st, M_TEMP); 1259 free(td_infos, M_TEMP); 1260 stacks_to_allocate *= 10; 1261 } 1262 1263 if (!finished && error == 0) 1264 error = ENOMEM; 1265 1266 return (error); 1267} 1268#endif 1269 1270#ifdef SLEEPQUEUE_PROFILING 1271#define SLEEPQ_PROF_LOCATIONS 1024 1272#define SLEEPQ_SBUFSIZE 512 1273struct sleepq_prof { 1274 LIST_ENTRY(sleepq_prof) sp_link; 1275 const char *sp_wmesg; 1276 long sp_count; 1277}; 1278 1279LIST_HEAD(sqphead, sleepq_prof); 1280 1281struct sqphead sleepq_prof_free; 1282struct sqphead sleepq_hash[SC_TABLESIZE]; 1283static struct sleepq_prof sleepq_profent[SLEEPQ_PROF_LOCATIONS]; 1284static struct mtx sleepq_prof_lock; 1285MTX_SYSINIT(sleepq_prof_lock, &sleepq_prof_lock, "sleepq_prof", MTX_SPIN); 1286 1287static void 1288sleepq_profile(const char *wmesg) 1289{ 1290 struct sleepq_prof *sp; 1291 1292 mtx_lock_spin(&sleepq_prof_lock); 1293 if (prof_enabled == 0) 1294 goto unlock; 1295 LIST_FOREACH(sp, &sleepq_hash[SC_HASH(wmesg)], sp_link) 1296 if (sp->sp_wmesg == wmesg) 1297 goto done; 1298 sp = LIST_FIRST(&sleepq_prof_free); 1299 if (sp == NULL) 1300 goto unlock; 1301 sp->sp_wmesg = wmesg; 1302 LIST_REMOVE(sp, sp_link); 1303 LIST_INSERT_HEAD(&sleepq_hash[SC_HASH(wmesg)], sp, sp_link); 1304done: 1305 sp->sp_count++; 1306unlock: 1307 mtx_unlock_spin(&sleepq_prof_lock); 1308 return; 1309} 1310 1311static void 1312sleepq_prof_reset(void) 1313{ 1314 struct sleepq_prof *sp; 1315 int enabled; 1316 int i; 1317 1318 mtx_lock_spin(&sleepq_prof_lock); 1319 enabled = prof_enabled; 1320 prof_enabled = 0; 1321 for (i = 0; i < SC_TABLESIZE; i++) 1322 LIST_INIT(&sleepq_hash[i]); 1323 LIST_INIT(&sleepq_prof_free); 1324 for (i = 0; i < SLEEPQ_PROF_LOCATIONS; i++) { 1325 sp = &sleepq_profent[i]; 1326 sp->sp_wmesg = NULL; 1327 sp->sp_count = 0; 1328 LIST_INSERT_HEAD(&sleepq_prof_free, sp, sp_link); 1329 } 1330 prof_enabled = enabled; 1331 mtx_unlock_spin(&sleepq_prof_lock); 1332} 1333 1334static int 1335enable_sleepq_prof(SYSCTL_HANDLER_ARGS) 1336{ 1337 int error, v; 1338 1339 v = prof_enabled; 1340 error = sysctl_handle_int(oidp, &v, v, req); 1341 if (error) 1342 return (error); 1343 if (req->newptr == NULL) 1344 return (error); 1345 if (v == prof_enabled) 1346 return (0); 1347 if (v == 1) 1348 sleepq_prof_reset(); 1349 mtx_lock_spin(&sleepq_prof_lock); 1350 prof_enabled = !!v; 1351 mtx_unlock_spin(&sleepq_prof_lock); 1352 1353 return (0); 1354} 1355 1356static int 1357reset_sleepq_prof_stats(SYSCTL_HANDLER_ARGS) 1358{ 1359 int error, v; 1360 1361 v = 0; 1362 error = sysctl_handle_int(oidp, &v, 0, req); 1363 if (error) 1364 return (error); 1365 if (req->newptr == NULL) 1366 return (error); 1367 if (v == 0) 1368 return (0); 1369 sleepq_prof_reset(); 1370 1371 return (0); 1372} 1373 1374static int 1375dump_sleepq_prof_stats(SYSCTL_HANDLER_ARGS) 1376{ 1377 struct sleepq_prof *sp; 1378 struct sbuf *sb; 1379 int enabled; 1380 int error; 1381 int i; 1382 1383 error = sysctl_wire_old_buffer(req, 0); 1384 if (error != 0) 1385 return (error); 1386 sb = sbuf_new_for_sysctl(NULL, NULL, SLEEPQ_SBUFSIZE, req); 1387 sbuf_printf(sb, "\nwmesg\tcount\n"); 1388 enabled = prof_enabled; 1389 mtx_lock_spin(&sleepq_prof_lock); 1390 prof_enabled = 0; 1391 mtx_unlock_spin(&sleepq_prof_lock); 1392 for (i = 0; i < SC_TABLESIZE; i++) { 1393 LIST_FOREACH(sp, &sleepq_hash[i], sp_link) { 1394 sbuf_printf(sb, "%s\t%ld\n", 1395 sp->sp_wmesg, sp->sp_count); 1396 } 1397 } 1398 mtx_lock_spin(&sleepq_prof_lock); 1399 prof_enabled = enabled; 1400 mtx_unlock_spin(&sleepq_prof_lock); 1401 1402 error = sbuf_finish(sb); 1403 sbuf_delete(sb); 1404 return (error); 1405} 1406 1407SYSCTL_PROC(_debug_sleepq, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD, 1408 NULL, 0, dump_sleepq_prof_stats, "A", "Sleepqueue profiling statistics"); 1409SYSCTL_PROC(_debug_sleepq, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW, 1410 NULL, 0, reset_sleepq_prof_stats, "I", 1411 "Reset sleepqueue profiling statistics"); 1412SYSCTL_PROC(_debug_sleepq, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW, 1413 NULL, 0, enable_sleepq_prof, "I", "Enable sleepqueue profiling"); 1414#endif 1415 1416#ifdef DDB 1417DB_SHOW_COMMAND(sleepq, db_show_sleepqueue) 1418{ 1419 struct sleepqueue_chain *sc; 1420 struct sleepqueue *sq; 1421#ifdef INVARIANTS 1422 struct lock_object *lock; 1423#endif 1424 struct thread *td; 1425 void *wchan; 1426 int i; 1427 1428 if (!have_addr) 1429 return; 1430 1431 /* 1432 * First, see if there is an active sleep queue for the wait channel 1433 * indicated by the address. 1434 */ 1435 wchan = (void *)addr; 1436 sc = SC_LOOKUP(wchan); 1437 LIST_FOREACH(sq, &sc->sc_queues, sq_hash) 1438 if (sq->sq_wchan == wchan) 1439 goto found; 1440 1441 /* 1442 * Second, see if there is an active sleep queue at the address 1443 * indicated. 1444 */ 1445 for (i = 0; i < SC_TABLESIZE; i++) 1446 LIST_FOREACH(sq, &sleepq_chains[i].sc_queues, sq_hash) { 1447 if (sq == (struct sleepqueue *)addr) 1448 goto found; 1449 } 1450 1451 db_printf("Unable to locate a sleep queue via %p\n", (void *)addr); 1452 return; 1453found: 1454 db_printf("Wait channel: %p\n", sq->sq_wchan); 1455 db_printf("Queue type: %d\n", sq->sq_type); 1456#ifdef INVARIANTS 1457 if (sq->sq_lock) { 1458 lock = sq->sq_lock; 1459 db_printf("Associated Interlock: %p - (%s) %s\n", lock, 1460 LOCK_CLASS(lock)->lc_name, lock->lo_name); 1461 } 1462#endif 1463 db_printf("Blocked threads:\n"); 1464 for (i = 0; i < NR_SLEEPQS; i++) { 1465 db_printf("\nQueue[%d]:\n", i); 1466 if (TAILQ_EMPTY(&sq->sq_blocked[i])) 1467 db_printf("\tempty\n"); 1468 else 1469 TAILQ_FOREACH(td, &sq->sq_blocked[i], 1470 td_slpq) { 1471 db_printf("\t%p (tid %d, pid %d, \"%s\")\n", td, 1472 td->td_tid, td->td_proc->p_pid, 1473 td->td_name); 1474 } 1475 db_printf("(expected: %u)\n", sq->sq_blockedcnt[i]); 1476 } 1477} 1478 1479/* Alias 'show sleepqueue' to 'show sleepq'. */ 1480DB_SHOW_ALIAS(sleepqueue, db_show_sleepqueue); 1481#endif 1482