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("$FreeBSD$");
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 */
120 struct 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
132 struct 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
142 u_int sleepq_max_depth;
143 static SYSCTL_NODE(_debug, OID_AUTO, sleepq, CTLFLAG_RD, 0, "sleepq profiling");
144 static SYSCTL_NODE(_debug_sleepq, OID_AUTO, chains, CTLFLAG_RD, 0,
145 "sleepq chain stats");
146 SYSCTL_UINT(_debug_sleepq, OID_AUTO, max_depth, CTLFLAG_RD, &sleepq_max_depth,
147 0, "maxmimum depth achieved of a single chain");
148
149 static void sleepq_profile(const char *wmesg);
150 static int prof_enabled;
151 #endif
152 static struct sleepqueue_chain sleepq_chains[SC_TABLESIZE];
153 static uma_zone_t sleepq_zone;
154
155 /*
156 * Prototypes for non-exported routines.
157 */
158 static int sleepq_catch_signals(void *wchan, int pri);
159 static int sleepq_check_signals(void);
160 static int sleepq_check_timeout(void);
161 #ifdef INVARIANTS
162 static void sleepq_dtor(void *mem, int size, void *arg);
163 #endif
164 static int sleepq_init(void *mem, int size, int flags);
165 static int sleepq_resume_thread(struct sleepqueue *sq, struct thread *td,
166 int pri);
167 static void sleepq_switch(void *wchan, int pri);
168 static void sleepq_timeout(void *arg);
169
170 SDT_PROBE_DECLARE(sched, , , sleep);
171 SDT_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
179 static void
180 init_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
199 SYSINIT(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 */
207 void
208 init_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 */
230 struct sleepqueue *
231 sleepq_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 */
240 void
241 sleepq_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 */
250 void
251 sleepq_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 */
264 struct sleepqueue *
265 sleepq_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 */
282 void
283 sleepq_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 */
297 void
298 sleepq_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 */
377 void
378 sleepq_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 */
406 u_int
407 sleepq_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 */
425 static int
426 sleepq_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 }
525 out:
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 */
551 static void
552 sleepq_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 */
629 static int
630 sleepq_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 */
668 static int
669 sleepq_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 */
691 void
692 sleepq_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 */
707 int
708 sleepq_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 */
725 int
726 sleepq_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 */
745 int
746 sleepq_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 */
764 int
765 sleepq_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 */
787 static int
788 sleepq_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 */
853 static void
854 sleepq_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 */
870 static int
871 sleepq_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 */
889 int
890 sleepq_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
942 static bool
943 match_any(struct thread *td __unused)
944 {
945
946 return (true);
947 }
948
949 /*
950 * Resume all threads sleeping on a specified wait channel.
951 */
952 int
953 sleepq_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 */
972 int
973 sleepq_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 */
1000 static void
1001 sleepq_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 */
1051 void
1052 sleepq_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 */
1090 int
1091 sleepq_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
1128 void
1129 sleepq_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
1161 int
1162 sleepq_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
1249 loop_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
1273 struct sleepq_prof {
1274 LIST_ENTRY(sleepq_prof) sp_link;
1275 const char *sp_wmesg;
1276 long sp_count;
1277 };
1278
1279 LIST_HEAD(sqphead, sleepq_prof);
1280
1281 struct sqphead sleepq_prof_free;
1282 struct sqphead sleepq_hash[SC_TABLESIZE];
1283 static struct sleepq_prof sleepq_profent[SLEEPQ_PROF_LOCATIONS];
1284 static struct mtx sleepq_prof_lock;
1285 MTX_SYSINIT(sleepq_prof_lock, &sleepq_prof_lock, "sleepq_prof", MTX_SPIN);
1286
1287 static void
1288 sleepq_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);
1304 done:
1305 sp->sp_count++;
1306 unlock:
1307 mtx_unlock_spin(&sleepq_prof_lock);
1308 return;
1309 }
1310
1311 static void
1312 sleepq_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
1334 static int
1335 enable_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
1356 static int
1357 reset_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
1374 static int
1375 dump_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
1407 SYSCTL_PROC(_debug_sleepq, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD,
1408 NULL, 0, dump_sleepq_prof_stats, "A", "Sleepqueue profiling statistics");
1409 SYSCTL_PROC(_debug_sleepq, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW,
1410 NULL, 0, reset_sleepq_prof_stats, "I",
1411 "Reset sleepqueue profiling statistics");
1412 SYSCTL_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
1417 DB_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;
1453 found:
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'. */
1480 DB_SHOW_ALIAS(sleepqueue, db_show_sleepqueue);
1481 #endif
Cache object: 0d7fc652e9b7ad5477dc9b0c6b34133e
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