1/*
2 * Copyright (c) 2004 John Baldwin <jhb@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 * 3. Neither the name of the author nor the names of any co-contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30/*
31 * Implementation of sleep queues used to hold queue of threads blocked on
32 * a wait channel. Sleep queues different from turnstiles in that wait
33 * channels are not owned by anyone, so there is no priority propagation.
34 * Sleep queues can also provide a timeout and can also be interrupted by
35 * signals. That said, there are several similarities between the turnstile
36 * and sleep queue implementations. (Note: turnstiles were implemented
37 * first.) For example, both use a hash table of the same size where each
38 * bucket is referred to as a "chain" that contains both a spin lock and
39 * a linked list of queues. An individual queue is located by using a hash
40 * to pick a chain, locking the chain, and then walking the chain searching
41 * for the queue. This means that a wait channel object does not need to
42 * embed it's queue head just as locks do not embed their turnstile queue
43 * head. Threads also carry around a sleep queue that they lend to the
44 * wait channel when blocking. Just as in turnstiles, the queue includes
45 * a free list of the sleep queues of other threads blocked on the same
46 * wait channel in the case of multiple waiters.
47 *
48 * Some additional functionality provided by sleep queues include the
49 * ability to set a timeout. The timeout is managed using a per-thread
50 * callout that resumes a thread if it is asleep. A thread may also
51 * catch signals while it is asleep (aka an interruptible sleep). The
52 * signal code uses sleepq_abort() to interrupt a sleeping thread. Finally,
53 * sleep queues also provide some extra assertions. One is not allowed to
54 * mix the sleep/wakeup and cv APIs for a given wait channel. Also, one
55 * must consistently use the same lock to synchronize with a wait channel,
56 * though this check is currently only a warning for sleep/wakeup due to
57 * pre-existing abuse of that API. The same lock must also be held when
58 * awakening threads, though that is currently only enforced for condition
59 * variables.
60 */
61
62#include "opt_sleepqueue_profiling.h"
63
64#include <sys/cdefs.h>
| 1/*
2 * Copyright (c) 2004 John Baldwin <jhb@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 * 3. Neither the name of the author nor the names of any co-contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30/*
31 * Implementation of sleep queues used to hold queue of threads blocked on
32 * a wait channel. Sleep queues different from turnstiles in that wait
33 * channels are not owned by anyone, so there is no priority propagation.
34 * Sleep queues can also provide a timeout and can also be interrupted by
35 * signals. That said, there are several similarities between the turnstile
36 * and sleep queue implementations. (Note: turnstiles were implemented
37 * first.) For example, both use a hash table of the same size where each
38 * bucket is referred to as a "chain" that contains both a spin lock and
39 * a linked list of queues. An individual queue is located by using a hash
40 * to pick a chain, locking the chain, and then walking the chain searching
41 * for the queue. This means that a wait channel object does not need to
42 * embed it's queue head just as locks do not embed their turnstile queue
43 * head. Threads also carry around a sleep queue that they lend to the
44 * wait channel when blocking. Just as in turnstiles, the queue includes
45 * a free list of the sleep queues of other threads blocked on the same
46 * wait channel in the case of multiple waiters.
47 *
48 * Some additional functionality provided by sleep queues include the
49 * ability to set a timeout. The timeout is managed using a per-thread
50 * callout that resumes a thread if it is asleep. A thread may also
51 * catch signals while it is asleep (aka an interruptible sleep). The
52 * signal code uses sleepq_abort() to interrupt a sleeping thread. Finally,
53 * sleep queues also provide some extra assertions. One is not allowed to
54 * mix the sleep/wakeup and cv APIs for a given wait channel. Also, one
55 * must consistently use the same lock to synchronize with a wait channel,
56 * though this check is currently only a warning for sleep/wakeup due to
57 * pre-existing abuse of that API. The same lock must also be held when
58 * awakening threads, though that is currently only enforced for condition
59 * variables.
60 */
61
62#include "opt_sleepqueue_profiling.h"
63
64#include <sys/cdefs.h>
|
65__FBSDID("$FreeBSD: head/sys/kern/subr_sleepqueue.c 131473 2004-07-02 19:09:50Z jhb $");
| 65__FBSDID("$FreeBSD: head/sys/kern/subr_sleepqueue.c 134013 2004-08-19 11:31:42Z jhb $");
|
66
67#include <sys/param.h>
68#include <sys/systm.h>
69#include <sys/lock.h>
70#include <sys/kernel.h>
71#include <sys/ktr.h>
72#include <sys/malloc.h>
73#include <sys/mutex.h>
74#include <sys/proc.h>
75#include <sys/sched.h>
76#include <sys/signalvar.h>
77#include <sys/sleepqueue.h>
78#include <sys/sysctl.h>
79
80/*
81 * Constants for the hash table of sleep queue chains. These constants are
82 * the same ones that 4BSD (and possibly earlier versions of BSD) used.
83 * Basically, we ignore the lower 8 bits of the address since most wait
84 * channel pointers are aligned and only look at the next 7 bits for the
85 * hash. SC_TABLESIZE must be a power of two for SC_MASK to work properly.
86 */
87#define SC_TABLESIZE 128 /* Must be power of 2. */
88#define SC_MASK (SC_TABLESIZE - 1)
89#define SC_SHIFT 8
90#define SC_HASH(wc) (((uintptr_t)(wc) >> SC_SHIFT) & SC_MASK)
91#define SC_LOOKUP(wc) &sleepq_chains[SC_HASH(wc)]
92
93/*
94 * There two different lists of sleep queues. Both lists are connected
95 * via the sq_hash entries. The first list is the sleep queue chain list
96 * that a sleep queue is on when it is attached to a wait channel. The
97 * second list is the free list hung off of a sleep queue that is attached
98 * to a wait channel.
99 *
100 * Each sleep queue also contains the wait channel it is attached to, the
101 * list of threads blocked on that wait channel, flags specific to the
102 * wait channel, and the lock used to synchronize with a wait channel.
103 * The flags are used to catch mismatches between the various consumers
104 * of the sleep queue API (e.g. sleep/wakeup and condition variables).
105 * The lock pointer is only used when invariants are enabled for various
106 * debugging checks.
107 *
108 * Locking key:
109 * c - sleep queue chain lock
110 */
111struct sleepqueue {
112 TAILQ_HEAD(, thread) sq_blocked; /* (c) Blocked threads. */
113 LIST_ENTRY(sleepqueue) sq_hash; /* (c) Chain and free list. */
114 LIST_HEAD(, sleepqueue) sq_free; /* (c) Free queues. */
115 void *sq_wchan; /* (c) Wait channel. */
| 66
67#include <sys/param.h>
68#include <sys/systm.h>
69#include <sys/lock.h>
70#include <sys/kernel.h>
71#include <sys/ktr.h>
72#include <sys/malloc.h>
73#include <sys/mutex.h>
74#include <sys/proc.h>
75#include <sys/sched.h>
76#include <sys/signalvar.h>
77#include <sys/sleepqueue.h>
78#include <sys/sysctl.h>
79
80/*
81 * Constants for the hash table of sleep queue chains. These constants are
82 * the same ones that 4BSD (and possibly earlier versions of BSD) used.
83 * Basically, we ignore the lower 8 bits of the address since most wait
84 * channel pointers are aligned and only look at the next 7 bits for the
85 * hash. SC_TABLESIZE must be a power of two for SC_MASK to work properly.
86 */
87#define SC_TABLESIZE 128 /* Must be power of 2. */
88#define SC_MASK (SC_TABLESIZE - 1)
89#define SC_SHIFT 8
90#define SC_HASH(wc) (((uintptr_t)(wc) >> SC_SHIFT) & SC_MASK)
91#define SC_LOOKUP(wc) &sleepq_chains[SC_HASH(wc)]
92
93/*
94 * There two different lists of sleep queues. Both lists are connected
95 * via the sq_hash entries. The first list is the sleep queue chain list
96 * that a sleep queue is on when it is attached to a wait channel. The
97 * second list is the free list hung off of a sleep queue that is attached
98 * to a wait channel.
99 *
100 * Each sleep queue also contains the wait channel it is attached to, the
101 * list of threads blocked on that wait channel, flags specific to the
102 * wait channel, and the lock used to synchronize with a wait channel.
103 * The flags are used to catch mismatches between the various consumers
104 * of the sleep queue API (e.g. sleep/wakeup and condition variables).
105 * The lock pointer is only used when invariants are enabled for various
106 * debugging checks.
107 *
108 * Locking key:
109 * c - sleep queue chain lock
110 */
111struct sleepqueue {
112 TAILQ_HEAD(, thread) sq_blocked; /* (c) Blocked threads. */
113 LIST_ENTRY(sleepqueue) sq_hash; /* (c) Chain and free list. */
114 LIST_HEAD(, sleepqueue) sq_free; /* (c) Free queues. */
115 void *sq_wchan; /* (c) Wait channel. */
|
116 int sq_flags; /* (c) Flags. */
| 116 int sq_type; /* (c) Queue type. */
|
117#ifdef INVARIANTS
118 struct mtx *sq_lock; /* (c) Associated lock. */
119#endif
120};
121
122struct sleepqueue_chain {
123 LIST_HEAD(, sleepqueue) sc_queues; /* List of sleep queues. */
124 struct mtx sc_lock; /* Spin lock for this chain. */
125#ifdef SLEEPQUEUE_PROFILING
126 u_int sc_depth; /* Length of sc_queues. */
127 u_int sc_max_depth; /* Max length of sc_queues. */
128#endif
129};
130
131#ifdef SLEEPQUEUE_PROFILING
132u_int sleepq_max_depth;
133SYSCTL_NODE(_debug, OID_AUTO, sleepq, CTLFLAG_RD, 0, "sleepq profiling");
134SYSCTL_NODE(_debug_sleepq, OID_AUTO, chains, CTLFLAG_RD, 0,
135 "sleepq chain stats");
136SYSCTL_UINT(_debug_sleepq, OID_AUTO, max_depth, CTLFLAG_RD, &sleepq_max_depth,
137 0, "maxmimum depth achieved of a single chain");
138#endif
139static struct sleepqueue_chain sleepq_chains[SC_TABLESIZE];
140
141MALLOC_DEFINE(M_SLEEPQUEUE, "sleep queues", "sleep queues");
142
143/*
144 * Prototypes for non-exported routines.
145 */
146static int sleepq_check_timeout(void);
147static void sleepq_switch(void *wchan);
148static void sleepq_timeout(void *arg);
149static void sleepq_remove_thread(struct sleepqueue *sq, struct thread *td);
150static void sleepq_resume_thread(struct thread *td, int pri);
151
152/*
153 * Early initialization of sleep queues that is called from the sleepinit()
154 * SYSINIT.
155 */
156void
157init_sleepqueues(void)
158{
159#ifdef SLEEPQUEUE_PROFILING
160 struct sysctl_oid *chain_oid;
161 char chain_name[10];
162#endif
163 int i;
164
165 for (i = 0; i < SC_TABLESIZE; i++) {
166 LIST_INIT(&sleepq_chains[i].sc_queues);
167 mtx_init(&sleepq_chains[i].sc_lock, "sleepq chain", NULL,
168 MTX_SPIN);
169#ifdef SLEEPQUEUE_PROFILING
170 snprintf(chain_name, sizeof(chain_name), "%d", i);
171 chain_oid = SYSCTL_ADD_NODE(NULL,
172 SYSCTL_STATIC_CHILDREN(_debug_sleepq_chains), OID_AUTO,
173 chain_name, CTLFLAG_RD, NULL, "sleepq chain stats");
174 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
175 "depth", CTLFLAG_RD, &sleepq_chains[i].sc_depth, 0, NULL);
176 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
177 "max_depth", CTLFLAG_RD, &sleepq_chains[i].sc_max_depth, 0,
178 NULL);
179#endif
180 }
181 thread0.td_sleepqueue = sleepq_alloc();
182}
183
184/*
185 * Malloc and initialize a new sleep queue for a new thread.
186 */
187struct sleepqueue *
188sleepq_alloc(void)
189{
190 struct sleepqueue *sq;
191
192 sq = malloc(sizeof(struct sleepqueue), M_SLEEPQUEUE, M_WAITOK | M_ZERO);
193 TAILQ_INIT(&sq->sq_blocked);
194 LIST_INIT(&sq->sq_free);
195 return (sq);
196}
197
198/*
199 * Free a sleep queue when a thread is destroyed.
200 */
201void
202sleepq_free(struct sleepqueue *sq)
203{
204
205 MPASS(sq != NULL);
206 MPASS(TAILQ_EMPTY(&sq->sq_blocked));
207 free(sq, M_SLEEPQUEUE);
208}
209
210/*
211 * Look up the sleep queue associated with a given wait channel in the hash
212 * table locking the associated sleep queue chain. Return holdind the sleep
213 * queue chain lock. If no queue is found in the table, NULL is returned.
214 */
215struct sleepqueue *
216sleepq_lookup(void *wchan)
217{
218 struct sleepqueue_chain *sc;
219 struct sleepqueue *sq;
220
221 KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
222 sc = SC_LOOKUP(wchan);
223 mtx_lock_spin(&sc->sc_lock);
224 LIST_FOREACH(sq, &sc->sc_queues, sq_hash)
225 if (sq->sq_wchan == wchan)
226 return (sq);
227 return (NULL);
228}
229
230/*
231 * Unlock the sleep queue chain associated with a given wait channel.
232 */
233void
234sleepq_release(void *wchan)
235{
236 struct sleepqueue_chain *sc;
237
238 sc = SC_LOOKUP(wchan);
239 mtx_unlock_spin(&sc->sc_lock);
240}
241
242/*
243 * Places the current thread on the sleepqueue for the specified wait
244 * channel. If INVARIANTS is enabled, then it associates the passed in
245 * lock with the sleepq to make sure it is held when that sleep queue is
246 * woken up.
247 */
248void
249sleepq_add(struct sleepqueue *sq, void *wchan, struct mtx *lock,
250 const char *wmesg, int flags)
251{
252 struct sleepqueue_chain *sc;
253 struct thread *td, *td1;
254
255 td = curthread;
256 sc = SC_LOOKUP(wchan);
257 mtx_assert(&sc->sc_lock, MA_OWNED);
258 MPASS(td->td_sleepqueue != NULL);
259 MPASS(wchan != NULL);
260
261 /* If the passed in sleep queue is NULL, use this thread's queue. */
262 if (sq == NULL) {
263#ifdef SLEEPQUEUE_PROFILING
264 sc->sc_depth++;
265 if (sc->sc_depth > sc->sc_max_depth) {
266 sc->sc_max_depth = sc->sc_depth;
267 if (sc->sc_max_depth > sleepq_max_depth)
268 sleepq_max_depth = sc->sc_max_depth;
269 }
270#endif
271 sq = td->td_sleepqueue;
272 LIST_INSERT_HEAD(&sc->sc_queues, sq, sq_hash);
273 KASSERT(TAILQ_EMPTY(&sq->sq_blocked),
274 ("thread's sleep queue has a non-empty queue"));
275 KASSERT(LIST_EMPTY(&sq->sq_free),
276 ("thread's sleep queue has a non-empty free list"));
277 KASSERT(sq->sq_wchan == NULL, ("stale sq_wchan pointer"));
278 sq->sq_wchan = wchan;
279#ifdef INVARIANTS
280 sq->sq_lock = lock;
281#endif
| 117#ifdef INVARIANTS
118 struct mtx *sq_lock; /* (c) Associated lock. */
119#endif
120};
121
122struct sleepqueue_chain {
123 LIST_HEAD(, sleepqueue) sc_queues; /* List of sleep queues. */
124 struct mtx sc_lock; /* Spin lock for this chain. */
125#ifdef SLEEPQUEUE_PROFILING
126 u_int sc_depth; /* Length of sc_queues. */
127 u_int sc_max_depth; /* Max length of sc_queues. */
128#endif
129};
130
131#ifdef SLEEPQUEUE_PROFILING
132u_int sleepq_max_depth;
133SYSCTL_NODE(_debug, OID_AUTO, sleepq, CTLFLAG_RD, 0, "sleepq profiling");
134SYSCTL_NODE(_debug_sleepq, OID_AUTO, chains, CTLFLAG_RD, 0,
135 "sleepq chain stats");
136SYSCTL_UINT(_debug_sleepq, OID_AUTO, max_depth, CTLFLAG_RD, &sleepq_max_depth,
137 0, "maxmimum depth achieved of a single chain");
138#endif
139static struct sleepqueue_chain sleepq_chains[SC_TABLESIZE];
140
141MALLOC_DEFINE(M_SLEEPQUEUE, "sleep queues", "sleep queues");
142
143/*
144 * Prototypes for non-exported routines.
145 */
146static int sleepq_check_timeout(void);
147static void sleepq_switch(void *wchan);
148static void sleepq_timeout(void *arg);
149static void sleepq_remove_thread(struct sleepqueue *sq, struct thread *td);
150static void sleepq_resume_thread(struct thread *td, int pri);
151
152/*
153 * Early initialization of sleep queues that is called from the sleepinit()
154 * SYSINIT.
155 */
156void
157init_sleepqueues(void)
158{
159#ifdef SLEEPQUEUE_PROFILING
160 struct sysctl_oid *chain_oid;
161 char chain_name[10];
162#endif
163 int i;
164
165 for (i = 0; i < SC_TABLESIZE; i++) {
166 LIST_INIT(&sleepq_chains[i].sc_queues);
167 mtx_init(&sleepq_chains[i].sc_lock, "sleepq chain", NULL,
168 MTX_SPIN);
169#ifdef SLEEPQUEUE_PROFILING
170 snprintf(chain_name, sizeof(chain_name), "%d", i);
171 chain_oid = SYSCTL_ADD_NODE(NULL,
172 SYSCTL_STATIC_CHILDREN(_debug_sleepq_chains), OID_AUTO,
173 chain_name, CTLFLAG_RD, NULL, "sleepq chain stats");
174 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
175 "depth", CTLFLAG_RD, &sleepq_chains[i].sc_depth, 0, NULL);
176 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
177 "max_depth", CTLFLAG_RD, &sleepq_chains[i].sc_max_depth, 0,
178 NULL);
179#endif
180 }
181 thread0.td_sleepqueue = sleepq_alloc();
182}
183
184/*
185 * Malloc and initialize a new sleep queue for a new thread.
186 */
187struct sleepqueue *
188sleepq_alloc(void)
189{
190 struct sleepqueue *sq;
191
192 sq = malloc(sizeof(struct sleepqueue), M_SLEEPQUEUE, M_WAITOK | M_ZERO);
193 TAILQ_INIT(&sq->sq_blocked);
194 LIST_INIT(&sq->sq_free);
195 return (sq);
196}
197
198/*
199 * Free a sleep queue when a thread is destroyed.
200 */
201void
202sleepq_free(struct sleepqueue *sq)
203{
204
205 MPASS(sq != NULL);
206 MPASS(TAILQ_EMPTY(&sq->sq_blocked));
207 free(sq, M_SLEEPQUEUE);
208}
209
210/*
211 * Look up the sleep queue associated with a given wait channel in the hash
212 * table locking the associated sleep queue chain. Return holdind the sleep
213 * queue chain lock. If no queue is found in the table, NULL is returned.
214 */
215struct sleepqueue *
216sleepq_lookup(void *wchan)
217{
218 struct sleepqueue_chain *sc;
219 struct sleepqueue *sq;
220
221 KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
222 sc = SC_LOOKUP(wchan);
223 mtx_lock_spin(&sc->sc_lock);
224 LIST_FOREACH(sq, &sc->sc_queues, sq_hash)
225 if (sq->sq_wchan == wchan)
226 return (sq);
227 return (NULL);
228}
229
230/*
231 * Unlock the sleep queue chain associated with a given wait channel.
232 */
233void
234sleepq_release(void *wchan)
235{
236 struct sleepqueue_chain *sc;
237
238 sc = SC_LOOKUP(wchan);
239 mtx_unlock_spin(&sc->sc_lock);
240}
241
242/*
243 * Places the current thread on the sleepqueue for the specified wait
244 * channel. If INVARIANTS is enabled, then it associates the passed in
245 * lock with the sleepq to make sure it is held when that sleep queue is
246 * woken up.
247 */
248void
249sleepq_add(struct sleepqueue *sq, void *wchan, struct mtx *lock,
250 const char *wmesg, int flags)
251{
252 struct sleepqueue_chain *sc;
253 struct thread *td, *td1;
254
255 td = curthread;
256 sc = SC_LOOKUP(wchan);
257 mtx_assert(&sc->sc_lock, MA_OWNED);
258 MPASS(td->td_sleepqueue != NULL);
259 MPASS(wchan != NULL);
260
261 /* If the passed in sleep queue is NULL, use this thread's queue. */
262 if (sq == NULL) {
263#ifdef SLEEPQUEUE_PROFILING
264 sc->sc_depth++;
265 if (sc->sc_depth > sc->sc_max_depth) {
266 sc->sc_max_depth = sc->sc_depth;
267 if (sc->sc_max_depth > sleepq_max_depth)
268 sleepq_max_depth = sc->sc_max_depth;
269 }
270#endif
271 sq = td->td_sleepqueue;
272 LIST_INSERT_HEAD(&sc->sc_queues, sq, sq_hash);
273 KASSERT(TAILQ_EMPTY(&sq->sq_blocked),
274 ("thread's sleep queue has a non-empty queue"));
275 KASSERT(LIST_EMPTY(&sq->sq_free),
276 ("thread's sleep queue has a non-empty free list"));
277 KASSERT(sq->sq_wchan == NULL, ("stale sq_wchan pointer"));
278 sq->sq_wchan = wchan;
279#ifdef INVARIANTS
280 sq->sq_lock = lock;
281#endif
|
282 sq->sq_flags = flags;
| 282 sq->sq_type = flags & SLEEPQ_TYPE;
|
283 TAILQ_INSERT_TAIL(&sq->sq_blocked, td, td_slpq);
284 } else {
285 MPASS(wchan == sq->sq_wchan);
286 MPASS(lock == sq->sq_lock);
287 TAILQ_FOREACH(td1, &sq->sq_blocked, td_slpq)
288 if (td1->td_priority > td->td_priority)
289 break;
290 if (td1 != NULL)
291 TAILQ_INSERT_BEFORE(td1, td, td_slpq);
292 else
293 TAILQ_INSERT_TAIL(&sq->sq_blocked, td, td_slpq);
294 LIST_INSERT_HEAD(&sq->sq_free, td->td_sleepqueue, sq_hash);
295 }
296 td->td_sleepqueue = NULL;
297 mtx_lock_spin(&sched_lock);
298 td->td_wchan = wchan;
299 td->td_wmesg = wmesg;
| 283 TAILQ_INSERT_TAIL(&sq->sq_blocked, td, td_slpq);
284 } else {
285 MPASS(wchan == sq->sq_wchan);
286 MPASS(lock == sq->sq_lock);
287 TAILQ_FOREACH(td1, &sq->sq_blocked, td_slpq)
288 if (td1->td_priority > td->td_priority)
289 break;
290 if (td1 != NULL)
291 TAILQ_INSERT_BEFORE(td1, td, td_slpq);
292 else
293 TAILQ_INSERT_TAIL(&sq->sq_blocked, td, td_slpq);
294 LIST_INSERT_HEAD(&sq->sq_free, td->td_sleepqueue, sq_hash);
295 }
296 td->td_sleepqueue = NULL;
297 mtx_lock_spin(&sched_lock);
298 td->td_wchan = wchan;
299 td->td_wmesg = wmesg;
|
| 300 if (flags & SLEEPQ_INTERRUPTIBLE)
301 td->td_flags |= TDF_SINTR;
|
300 mtx_unlock_spin(&sched_lock);
301}
302
303/*
304 * Sets a timeout that will remove the current thread from the specified
305 * sleep queue after timo ticks if the thread has not already been awakened.
306 */
307void
308sleepq_set_timeout(void *wchan, int timo)
309{
310 struct sleepqueue_chain *sc;
311 struct thread *td;
312
313 td = curthread;
314 sc = SC_LOOKUP(wchan);
315 mtx_assert(&sc->sc_lock, MA_OWNED);
316 MPASS(TD_ON_SLEEPQ(td));
317 MPASS(td->td_sleepqueue == NULL);
318 MPASS(wchan != NULL);
319 callout_reset(&td->td_slpcallout, timo, sleepq_timeout, td);
320}
321
322/*
323 * Marks the pending sleep of the current thread as interruptible and
324 * makes an initial check for pending signals before putting a thread
325 * to sleep.
326 */
327int
328sleepq_catch_signals(void *wchan)
329{
330 struct sleepqueue_chain *sc;
331 struct sleepqueue *sq;
332 struct thread *td;
333 struct proc *p;
334 int do_upcall;
335 int sig;
336
337 do_upcall = 0;
338 td = curthread;
339 p = td->td_proc;
340 sc = SC_LOOKUP(wchan);
341 mtx_assert(&sc->sc_lock, MA_OWNED);
342 MPASS(td->td_sleepqueue == NULL);
343 MPASS(wchan != NULL);
344 CTR3(KTR_PROC, "sleepq catching signals: thread %p (pid %ld, %s)",
345 (void *)td, (long)p->p_pid, p->p_comm);
346
347 /* Mark thread as being in an interruptible sleep. */
| 302 mtx_unlock_spin(&sched_lock);
303}
304
305/*
306 * Sets a timeout that will remove the current thread from the specified
307 * sleep queue after timo ticks if the thread has not already been awakened.
308 */
309void
310sleepq_set_timeout(void *wchan, int timo)
311{
312 struct sleepqueue_chain *sc;
313 struct thread *td;
314
315 td = curthread;
316 sc = SC_LOOKUP(wchan);
317 mtx_assert(&sc->sc_lock, MA_OWNED);
318 MPASS(TD_ON_SLEEPQ(td));
319 MPASS(td->td_sleepqueue == NULL);
320 MPASS(wchan != NULL);
321 callout_reset(&td->td_slpcallout, timo, sleepq_timeout, td);
322}
323
324/*
325 * Marks the pending sleep of the current thread as interruptible and
326 * makes an initial check for pending signals before putting a thread
327 * to sleep.
328 */
329int
330sleepq_catch_signals(void *wchan)
331{
332 struct sleepqueue_chain *sc;
333 struct sleepqueue *sq;
334 struct thread *td;
335 struct proc *p;
336 int do_upcall;
337 int sig;
338
339 do_upcall = 0;
340 td = curthread;
341 p = td->td_proc;
342 sc = SC_LOOKUP(wchan);
343 mtx_assert(&sc->sc_lock, MA_OWNED);
344 MPASS(td->td_sleepqueue == NULL);
345 MPASS(wchan != NULL);
346 CTR3(KTR_PROC, "sleepq catching signals: thread %p (pid %ld, %s)",
347 (void *)td, (long)p->p_pid, p->p_comm);
348
349 /* Mark thread as being in an interruptible sleep. */
|
348 mtx_lock_spin(&sched_lock);
| 350 MPASS(td->td_flags & TDF_SINTR);
|
349 MPASS(TD_ON_SLEEPQ(td));
| 351 MPASS(TD_ON_SLEEPQ(td));
|
350 td->td_flags |= TDF_SINTR;
351 mtx_unlock_spin(&sched_lock);
| |
352 sleepq_release(wchan);
353
354 /* See if there are any pending signals for this thread. */
355 PROC_LOCK(p);
356 mtx_lock(&p->p_sigacts->ps_mtx);
357 sig = cursig(td);
358 mtx_unlock(&p->p_sigacts->ps_mtx);
359 if (sig == 0 && thread_suspend_check(1))
360 sig = SIGSTOP;
361 else
362 do_upcall = thread_upcall_check(td);
363 PROC_UNLOCK(p);
364
365 /*
366 * If there were pending signals and this thread is still on
| 352 sleepq_release(wchan);
353
354 /* See if there are any pending signals for this thread. */
355 PROC_LOCK(p);
356 mtx_lock(&p->p_sigacts->ps_mtx);
357 sig = cursig(td);
358 mtx_unlock(&p->p_sigacts->ps_mtx);
359 if (sig == 0 && thread_suspend_check(1))
360 sig = SIGSTOP;
361 else
362 do_upcall = thread_upcall_check(td);
363 PROC_UNLOCK(p);
364
365 /*
366 * If there were pending signals and this thread is still on
|
367 * the sleep queue, remove it from the sleep queue.
| 367 * the sleep queue, remove it from the sleep queue. If the
368 * thread was removed from the sleep queue while we were blocked
369 * above, then clear TDF_SINTR before returning.
|
368 */
369 sq = sleepq_lookup(wchan);
370 mtx_lock_spin(&sched_lock);
371 if (TD_ON_SLEEPQ(td) && (sig != 0 || do_upcall != 0)) {
372 mtx_unlock_spin(&sched_lock);
373 sleepq_remove_thread(sq, td);
| 370 */
371 sq = sleepq_lookup(wchan);
372 mtx_lock_spin(&sched_lock);
373 if (TD_ON_SLEEPQ(td) && (sig != 0 || do_upcall != 0)) {
374 mtx_unlock_spin(&sched_lock);
375 sleepq_remove_thread(sq, td);
|
374 } else
| 376 } else {
377 if (!TD_ON_SLEEPQ(td) && sig == 0)
378 td->td_flags &= ~TDF_SINTR;
|
375 mtx_unlock_spin(&sched_lock);
| 379 mtx_unlock_spin(&sched_lock);
|
| 380 }
|
376 return (sig);
377}
378
379/*
380 * Switches to another thread if we are still asleep on a sleep queue and
381 * drop the lock on the sleepqueue chain. Returns with sched_lock held.
382 */
383static void
384sleepq_switch(void *wchan)
385{
386 struct sleepqueue_chain *sc;
387 struct thread *td;
388
389 td = curthread;
390 sc = SC_LOOKUP(wchan);
391 mtx_assert(&sc->sc_lock, MA_OWNED);
392
393 /*
394 * If we have a sleep queue, then we've already been woken up, so
395 * just return.
396 */
397 if (td->td_sleepqueue != NULL) {
398 MPASS(!TD_ON_SLEEPQ(td));
399 mtx_unlock_spin(&sc->sc_lock);
400 mtx_lock_spin(&sched_lock);
401 return;
402 }
403
404 /*
405 * Otherwise, actually go to sleep.
406 */
407 mtx_lock_spin(&sched_lock);
408 mtx_unlock_spin(&sc->sc_lock);
409
410 sched_sleep(td);
411 TD_SET_SLEEPING(td);
412 mi_switch(SW_VOL, NULL);
413 KASSERT(TD_IS_RUNNING(td), ("running but not TDS_RUNNING"));
414 CTR3(KTR_PROC, "sleepq resume: thread %p (pid %ld, %s)",
415 (void *)td, (long)td->td_proc->p_pid, (void *)td->td_proc->p_comm);
416}
417
418/*
419 * Check to see if we timed out.
420 */
421static int
422sleepq_check_timeout(void)
423{
424 struct thread *td;
425
426 mtx_assert(&sched_lock, MA_OWNED);
427 td = curthread;
428
429 /*
430 * If TDF_TIMEOUT is set, we timed out.
431 */
432 if (td->td_flags & TDF_TIMEOUT) {
433 td->td_flags &= ~TDF_TIMEOUT;
434 return (EWOULDBLOCK);
435 }
436
437 /*
438 * If TDF_TIMOFAIL is set, the timeout ran after we had
439 * already been woken up.
440 */
441 if (td->td_flags & TDF_TIMOFAIL)
442 td->td_flags &= ~TDF_TIMOFAIL;
443
444 /*
445 * If callout_stop() fails, then the timeout is running on
446 * another CPU, so synchronize with it to avoid having it
447 * accidentally wake up a subsequent sleep.
448 */
449 else if (callout_stop(&td->td_slpcallout) == 0) {
450 td->td_flags |= TDF_TIMEOUT;
451 TD_SET_SLEEPING(td);
452 mi_switch(SW_INVOL, NULL);
453 }
454 return (0);
455}
456
457/*
458 * Check to see if we were awoken by a signal.
459 */
460static int
461sleepq_check_signals(void)
462{
463 struct thread *td;
464
465 mtx_assert(&sched_lock, MA_OWNED);
466 td = curthread;
467
| 381 return (sig);
382}
383
384/*
385 * Switches to another thread if we are still asleep on a sleep queue and
386 * drop the lock on the sleepqueue chain. Returns with sched_lock held.
387 */
388static void
389sleepq_switch(void *wchan)
390{
391 struct sleepqueue_chain *sc;
392 struct thread *td;
393
394 td = curthread;
395 sc = SC_LOOKUP(wchan);
396 mtx_assert(&sc->sc_lock, MA_OWNED);
397
398 /*
399 * If we have a sleep queue, then we've already been woken up, so
400 * just return.
401 */
402 if (td->td_sleepqueue != NULL) {
403 MPASS(!TD_ON_SLEEPQ(td));
404 mtx_unlock_spin(&sc->sc_lock);
405 mtx_lock_spin(&sched_lock);
406 return;
407 }
408
409 /*
410 * Otherwise, actually go to sleep.
411 */
412 mtx_lock_spin(&sched_lock);
413 mtx_unlock_spin(&sc->sc_lock);
414
415 sched_sleep(td);
416 TD_SET_SLEEPING(td);
417 mi_switch(SW_VOL, NULL);
418 KASSERT(TD_IS_RUNNING(td), ("running but not TDS_RUNNING"));
419 CTR3(KTR_PROC, "sleepq resume: thread %p (pid %ld, %s)",
420 (void *)td, (long)td->td_proc->p_pid, (void *)td->td_proc->p_comm);
421}
422
423/*
424 * Check to see if we timed out.
425 */
426static int
427sleepq_check_timeout(void)
428{
429 struct thread *td;
430
431 mtx_assert(&sched_lock, MA_OWNED);
432 td = curthread;
433
434 /*
435 * If TDF_TIMEOUT is set, we timed out.
436 */
437 if (td->td_flags & TDF_TIMEOUT) {
438 td->td_flags &= ~TDF_TIMEOUT;
439 return (EWOULDBLOCK);
440 }
441
442 /*
443 * If TDF_TIMOFAIL is set, the timeout ran after we had
444 * already been woken up.
445 */
446 if (td->td_flags & TDF_TIMOFAIL)
447 td->td_flags &= ~TDF_TIMOFAIL;
448
449 /*
450 * If callout_stop() fails, then the timeout is running on
451 * another CPU, so synchronize with it to avoid having it
452 * accidentally wake up a subsequent sleep.
453 */
454 else if (callout_stop(&td->td_slpcallout) == 0) {
455 td->td_flags |= TDF_TIMEOUT;
456 TD_SET_SLEEPING(td);
457 mi_switch(SW_INVOL, NULL);
458 }
459 return (0);
460}
461
462/*
463 * Check to see if we were awoken by a signal.
464 */
465static int
466sleepq_check_signals(void)
467{
468 struct thread *td;
469
470 mtx_assert(&sched_lock, MA_OWNED);
471 td = curthread;
472
|
| 473 /*
474 * If TDF_SINTR is clear, then we were awakened while executing
475 * sleepq_catch_signals().
476 */
477 if (!(td->td_flags & TDF_SINTR))
478 return (0);
479
|
468 /* We are no longer in an interruptible sleep. */
469 td->td_flags &= ~TDF_SINTR;
470
471 if (td->td_flags & TDF_INTERRUPT)
472 return (td->td_intrval);
473 return (0);
474}
475
476/*
477 * If we were in an interruptible sleep and we weren't interrupted and
478 * didn't timeout, check to see if there are any pending signals and
479 * which return value we should use if so. The return value from an
480 * earlier call to sleepq_catch_signals() should be passed in as the
481 * argument.
482 */
483int
484sleepq_calc_signal_retval(int sig)
485{
486 struct thread *td;
487 struct proc *p;
488 int rval;
489
490 td = curthread;
491 p = td->td_proc;
492 PROC_LOCK(p);
493 mtx_lock(&p->p_sigacts->ps_mtx);
494 /* XXX: Should we always be calling cursig()? */
495 if (sig == 0)
496 sig = cursig(td);
497 if (sig != 0) {
498 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
499 rval = EINTR;
500 else
501 rval = ERESTART;
502 } else
503 rval = 0;
504 mtx_unlock(&p->p_sigacts->ps_mtx);
505 PROC_UNLOCK(p);
506 return (rval);
507}
508
509/*
510 * Block the current thread until it is awakened from its sleep queue.
511 */
512void
513sleepq_wait(void *wchan)
514{
515
| 480 /* We are no longer in an interruptible sleep. */
481 td->td_flags &= ~TDF_SINTR;
482
483 if (td->td_flags & TDF_INTERRUPT)
484 return (td->td_intrval);
485 return (0);
486}
487
488/*
489 * If we were in an interruptible sleep and we weren't interrupted and
490 * didn't timeout, check to see if there are any pending signals and
491 * which return value we should use if so. The return value from an
492 * earlier call to sleepq_catch_signals() should be passed in as the
493 * argument.
494 */
495int
496sleepq_calc_signal_retval(int sig)
497{
498 struct thread *td;
499 struct proc *p;
500 int rval;
501
502 td = curthread;
503 p = td->td_proc;
504 PROC_LOCK(p);
505 mtx_lock(&p->p_sigacts->ps_mtx);
506 /* XXX: Should we always be calling cursig()? */
507 if (sig == 0)
508 sig = cursig(td);
509 if (sig != 0) {
510 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
511 rval = EINTR;
512 else
513 rval = ERESTART;
514 } else
515 rval = 0;
516 mtx_unlock(&p->p_sigacts->ps_mtx);
517 PROC_UNLOCK(p);
518 return (rval);
519}
520
521/*
522 * Block the current thread until it is awakened from its sleep queue.
523 */
524void
525sleepq_wait(void *wchan)
526{
527
|
| 528 MPASS(!(curthread->td_flags & TDF_SINTR));
|
516 sleepq_switch(wchan);
517 mtx_unlock_spin(&sched_lock);
518}
519
520/*
521 * Block the current thread until it is awakened from its sleep queue
522 * or it is interrupted by a signal.
523 */
524int
525sleepq_wait_sig(void *wchan)
526{
527 int rval;
528
529 sleepq_switch(wchan);
530 rval = sleepq_check_signals();
531 mtx_unlock_spin(&sched_lock);
532 return (rval);
533}
534
535/*
536 * Block the current thread until it is awakened from its sleep queue
537 * or it times out while waiting.
538 */
539int
540sleepq_timedwait(void *wchan)
541{
542 int rval;
543
| 529 sleepq_switch(wchan);
530 mtx_unlock_spin(&sched_lock);
531}
532
533/*
534 * Block the current thread until it is awakened from its sleep queue
535 * or it is interrupted by a signal.
536 */
537int
538sleepq_wait_sig(void *wchan)
539{
540 int rval;
541
542 sleepq_switch(wchan);
543 rval = sleepq_check_signals();
544 mtx_unlock_spin(&sched_lock);
545 return (rval);
546}
547
548/*
549 * Block the current thread until it is awakened from its sleep queue
550 * or it times out while waiting.
551 */
552int
553sleepq_timedwait(void *wchan)
554{
555 int rval;
556
|
| 557 MPASS(!(curthread->td_flags & TDF_SINTR));
|
544 sleepq_switch(wchan);
545 rval = sleepq_check_timeout();
546 mtx_unlock_spin(&sched_lock);
547 return (rval);
548}
549
550/*
551 * Block the current thread until it is awakened from its sleep queue,
552 * it is interrupted by a signal, or it times out waiting to be awakened.
553 */
554int
555sleepq_timedwait_sig(void *wchan, int signal_caught)
556{
557 int rvalt, rvals;
558
559 sleepq_switch(wchan);
560 rvalt = sleepq_check_timeout();
561 rvals = sleepq_check_signals();
562 mtx_unlock_spin(&sched_lock);
563 if (signal_caught || rvalt == 0)
564 return (rvals);
565 else
566 return (rvalt);
567}
568
569/*
570 * Removes a thread from a sleep queue.
571 */
572static void
573sleepq_remove_thread(struct sleepqueue *sq, struct thread *td)
574{
575 struct sleepqueue_chain *sc;
576
577 MPASS(td != NULL);
578 MPASS(sq->sq_wchan != NULL);
579 MPASS(td->td_wchan == sq->sq_wchan);
580 sc = SC_LOOKUP(sq->sq_wchan);
581 mtx_assert(&sc->sc_lock, MA_OWNED);
582
583 /* Remove the thread from the queue. */
584 TAILQ_REMOVE(&sq->sq_blocked, td, td_slpq);
585
586 /*
587 * Get a sleep queue for this thread. If this is the last waiter,
588 * use the queue itself and take it out of the chain, otherwise,
589 * remove a queue from the free list.
590 */
591 if (LIST_EMPTY(&sq->sq_free)) {
592 td->td_sleepqueue = sq;
593#ifdef INVARIANTS
594 sq->sq_wchan = NULL;
595#endif
596#ifdef SLEEPQUEUE_PROFILING
597 sc->sc_depth--;
598#endif
599 } else
600 td->td_sleepqueue = LIST_FIRST(&sq->sq_free);
601 LIST_REMOVE(td->td_sleepqueue, sq_hash);
602
603 mtx_lock_spin(&sched_lock);
604 td->td_wmesg = NULL;
605 td->td_wchan = NULL;
606 mtx_unlock_spin(&sched_lock);
607}
608
609/*
610 * Resumes a thread that was asleep on a queue.
611 */
612static void
613sleepq_resume_thread(struct thread *td, int pri)
614{
615
616 /*
617 * Note that thread td might not be sleeping if it is running
618 * sleepq_catch_signals() on another CPU or is blocked on
619 * its proc lock to check signals. It doesn't hurt to clear
620 * the sleeping flag if it isn't set though, so we just always
621 * do it. However, we can't assert that it is set.
622 */
623 mtx_lock_spin(&sched_lock);
624 CTR3(KTR_PROC, "sleepq_wakeup: thread %p (pid %ld, %s)",
625 (void *)td, (long)td->td_proc->p_pid, td->td_proc->p_comm);
626 TD_CLR_SLEEPING(td);
627
628 /* Adjust priority if requested. */
629 MPASS(pri == -1 || (pri >= PRI_MIN && pri <= PRI_MAX));
630 if (pri != -1 && td->td_priority > pri)
631 td->td_priority = pri;
632 setrunnable(td);
633 mtx_unlock_spin(&sched_lock);
634}
635
636/*
637 * Find the highest priority thread sleeping on a wait channel and resume it.
638 */
639void
640sleepq_signal(void *wchan, int flags, int pri)
641{
642 struct sleepqueue *sq;
643 struct thread *td;
644
645 CTR2(KTR_PROC, "sleepq_signal(%p, %d)", wchan, flags);
646 KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
647 sq = sleepq_lookup(wchan);
648 if (sq == NULL) {
649 sleepq_release(wchan);
650 return;
651 }
| 558 sleepq_switch(wchan);
559 rval = sleepq_check_timeout();
560 mtx_unlock_spin(&sched_lock);
561 return (rval);
562}
563
564/*
565 * Block the current thread until it is awakened from its sleep queue,
566 * it is interrupted by a signal, or it times out waiting to be awakened.
567 */
568int
569sleepq_timedwait_sig(void *wchan, int signal_caught)
570{
571 int rvalt, rvals;
572
573 sleepq_switch(wchan);
574 rvalt = sleepq_check_timeout();
575 rvals = sleepq_check_signals();
576 mtx_unlock_spin(&sched_lock);
577 if (signal_caught || rvalt == 0)
578 return (rvals);
579 else
580 return (rvalt);
581}
582
583/*
584 * Removes a thread from a sleep queue.
585 */
586static void
587sleepq_remove_thread(struct sleepqueue *sq, struct thread *td)
588{
589 struct sleepqueue_chain *sc;
590
591 MPASS(td != NULL);
592 MPASS(sq->sq_wchan != NULL);
593 MPASS(td->td_wchan == sq->sq_wchan);
594 sc = SC_LOOKUP(sq->sq_wchan);
595 mtx_assert(&sc->sc_lock, MA_OWNED);
596
597 /* Remove the thread from the queue. */
598 TAILQ_REMOVE(&sq->sq_blocked, td, td_slpq);
599
600 /*
601 * Get a sleep queue for this thread. If this is the last waiter,
602 * use the queue itself and take it out of the chain, otherwise,
603 * remove a queue from the free list.
604 */
605 if (LIST_EMPTY(&sq->sq_free)) {
606 td->td_sleepqueue = sq;
607#ifdef INVARIANTS
608 sq->sq_wchan = NULL;
609#endif
610#ifdef SLEEPQUEUE_PROFILING
611 sc->sc_depth--;
612#endif
613 } else
614 td->td_sleepqueue = LIST_FIRST(&sq->sq_free);
615 LIST_REMOVE(td->td_sleepqueue, sq_hash);
616
617 mtx_lock_spin(&sched_lock);
618 td->td_wmesg = NULL;
619 td->td_wchan = NULL;
620 mtx_unlock_spin(&sched_lock);
621}
622
623/*
624 * Resumes a thread that was asleep on a queue.
625 */
626static void
627sleepq_resume_thread(struct thread *td, int pri)
628{
629
630 /*
631 * Note that thread td might not be sleeping if it is running
632 * sleepq_catch_signals() on another CPU or is blocked on
633 * its proc lock to check signals. It doesn't hurt to clear
634 * the sleeping flag if it isn't set though, so we just always
635 * do it. However, we can't assert that it is set.
636 */
637 mtx_lock_spin(&sched_lock);
638 CTR3(KTR_PROC, "sleepq_wakeup: thread %p (pid %ld, %s)",
639 (void *)td, (long)td->td_proc->p_pid, td->td_proc->p_comm);
640 TD_CLR_SLEEPING(td);
641
642 /* Adjust priority if requested. */
643 MPASS(pri == -1 || (pri >= PRI_MIN && pri <= PRI_MAX));
644 if (pri != -1 && td->td_priority > pri)
645 td->td_priority = pri;
646 setrunnable(td);
647 mtx_unlock_spin(&sched_lock);
648}
649
650/*
651 * Find the highest priority thread sleeping on a wait channel and resume it.
652 */
653void
654sleepq_signal(void *wchan, int flags, int pri)
655{
656 struct sleepqueue *sq;
657 struct thread *td;
658
659 CTR2(KTR_PROC, "sleepq_signal(%p, %d)", wchan, flags);
660 KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
661 sq = sleepq_lookup(wchan);
662 if (sq == NULL) {
663 sleepq_release(wchan);
664 return;
665 }
|
652 KASSERT(sq->sq_flags == flags,
| 666 KASSERT(sq->sq_type == (flags & SLEEPQ_TYPE),
|
653 ("%s: mismatch between sleep/wakeup and cv_*", __func__));
654 /* XXX: Do for all sleep queues eventually. */
655 if (flags & SLEEPQ_CONDVAR)
656 mtx_assert(sq->sq_lock, MA_OWNED);
657
658 /* Remove first thread from queue and awaken it. */
659 td = TAILQ_FIRST(&sq->sq_blocked);
660 sleepq_remove_thread(sq, td);
661 sleepq_release(wchan);
662 sleepq_resume_thread(td, pri);
663}
664
665/*
666 * Resume all threads sleeping on a specified wait channel.
667 */
668void
669sleepq_broadcast(void *wchan, int flags, int pri)
670{
671 TAILQ_HEAD(, thread) list;
672 struct sleepqueue *sq;
673 struct thread *td;
674
675 CTR2(KTR_PROC, "sleepq_broadcast(%p, %d)", wchan, flags);
676 KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
677 sq = sleepq_lookup(wchan);
678 if (sq == NULL) {
679 sleepq_release(wchan);
680 return;
681 }
| 667 ("%s: mismatch between sleep/wakeup and cv_*", __func__));
668 /* XXX: Do for all sleep queues eventually. */
669 if (flags & SLEEPQ_CONDVAR)
670 mtx_assert(sq->sq_lock, MA_OWNED);
671
672 /* Remove first thread from queue and awaken it. */
673 td = TAILQ_FIRST(&sq->sq_blocked);
674 sleepq_remove_thread(sq, td);
675 sleepq_release(wchan);
676 sleepq_resume_thread(td, pri);
677}
678
679/*
680 * Resume all threads sleeping on a specified wait channel.
681 */
682void
683sleepq_broadcast(void *wchan, int flags, int pri)
684{
685 TAILQ_HEAD(, thread) list;
686 struct sleepqueue *sq;
687 struct thread *td;
688
689 CTR2(KTR_PROC, "sleepq_broadcast(%p, %d)", wchan, flags);
690 KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
691 sq = sleepq_lookup(wchan);
692 if (sq == NULL) {
693 sleepq_release(wchan);
694 return;
695 }
|
682 KASSERT(sq->sq_flags == flags,
| 696 KASSERT(sq->sq_type == (flags & SLEEPQ_TYPE),
|
683 ("%s: mismatch between sleep/wakeup and cv_*", __func__));
684 /* XXX: Do for all sleep queues eventually. */
685 if (flags & SLEEPQ_CONDVAR)
686 mtx_assert(sq->sq_lock, MA_OWNED);
687
688 /* Move blocked threads from the sleep queue to a temporary list. */
689 TAILQ_INIT(&list);
690 while (!TAILQ_EMPTY(&sq->sq_blocked)) {
691 td = TAILQ_FIRST(&sq->sq_blocked);
692 sleepq_remove_thread(sq, td);
693 TAILQ_INSERT_TAIL(&list, td, td_slpq);
694 }
695 sleepq_release(wchan);
696
697 /* Resume all the threads on the temporary list. */
698 while (!TAILQ_EMPTY(&list)) {
699 td = TAILQ_FIRST(&list);
700 TAILQ_REMOVE(&list, td, td_slpq);
701 sleepq_resume_thread(td, pri);
702 }
703}
704
705/*
706 * Time sleeping threads out. When the timeout expires, the thread is
707 * removed from the sleep queue and made runnable if it is still asleep.
708 */
709static void
710sleepq_timeout(void *arg)
711{
712 struct sleepqueue *sq;
713 struct thread *td;
714 void *wchan;
715
716 td = arg;
717 CTR3(KTR_PROC, "sleepq_timeout: thread %p (pid %ld, %s)",
718 (void *)td, (long)td->td_proc->p_pid, (void *)td->td_proc->p_comm);
719
720 /*
721 * First, see if the thread is asleep and get the wait channel if
722 * it is.
723 */
724 mtx_lock_spin(&sched_lock);
725 if (TD_ON_SLEEPQ(td)) {
726 wchan = td->td_wchan;
727 mtx_unlock_spin(&sched_lock);
728 sq = sleepq_lookup(wchan);
729 mtx_lock_spin(&sched_lock);
730 } else {
731 wchan = NULL;
732 sq = NULL;
733 }
734
735 /*
736 * At this point, if the thread is still on the sleep queue,
737 * we have that sleep queue locked as it cannot migrate sleep
738 * queues while we dropped sched_lock. If it had resumed and
739 * was on another CPU while the lock was dropped, it would have
740 * seen that TDF_TIMEOUT and TDF_TIMOFAIL are clear and the
741 * call to callout_stop() to stop this routine would have failed
742 * meaning that it would have already set TDF_TIMEOUT to
743 * synchronize with this function.
744 */
745 if (TD_ON_SLEEPQ(td)) {
746 MPASS(td->td_wchan == wchan);
747 MPASS(sq != NULL);
748 td->td_flags |= TDF_TIMEOUT;
749 mtx_unlock_spin(&sched_lock);
750 sleepq_remove_thread(sq, td);
751 sleepq_release(wchan);
752 sleepq_resume_thread(td, -1);
753 return;
754 } else if (wchan != NULL)
755 sleepq_release(wchan);
756
757 /*
758 * Now check for the edge cases. First, if TDF_TIMEOUT is set,
759 * then the other thread has already yielded to us, so clear
760 * the flag and resume it. If TDF_TIMEOUT is not set, then the
761 * we know that the other thread is not on a sleep queue, but it
762 * hasn't resumed execution yet. In that case, set TDF_TIMOFAIL
763 * to let it know that the timeout has already run and doesn't
764 * need to be canceled.
765 */
766 if (td->td_flags & TDF_TIMEOUT) {
767 MPASS(TD_IS_SLEEPING(td));
768 td->td_flags &= ~TDF_TIMEOUT;
769 TD_CLR_SLEEPING(td);
770 setrunnable(td);
771 } else
772 td->td_flags |= TDF_TIMOFAIL;
773 mtx_unlock_spin(&sched_lock);
774}
775
776/*
777 * Resumes a specific thread from the sleep queue associated with a specific
778 * wait channel if it is on that queue.
779 */
780void
781sleepq_remove(struct thread *td, void *wchan)
782{
783 struct sleepqueue *sq;
784
785 /*
786 * Look up the sleep queue for this wait channel, then re-check
787 * that the thread is asleep on that channel, if it is not, then
788 * bail.
789 */
790 MPASS(wchan != NULL);
791 sq = sleepq_lookup(wchan);
792 mtx_lock_spin(&sched_lock);
793 if (!TD_ON_SLEEPQ(td) || td->td_wchan != wchan) {
794 mtx_unlock_spin(&sched_lock);
795 sleepq_release(wchan);
796 return;
797 }
798 mtx_unlock_spin(&sched_lock);
799 MPASS(sq != NULL);
800
801 /* Thread is asleep on sleep queue sq, so wake it up. */
802 sleepq_remove_thread(sq, td);
803 sleepq_release(wchan);
804 sleepq_resume_thread(td, -1);
805}
806
807/*
808 * Abort a thread as if an interrupt had occurred. Only abort
809 * interruptible waits (unfortunately it isn't safe to abort others).
810 *
811 * XXX: What in the world does the comment below mean?
812 * Also, whatever the signal code does...
813 */
814void
815sleepq_abort(struct thread *td)
816{
817 void *wchan;
818
819 mtx_assert(&sched_lock, MA_OWNED);
820 MPASS(TD_ON_SLEEPQ(td));
821 MPASS(td->td_flags & TDF_SINTR);
822
823 /*
824 * If the TDF_TIMEOUT flag is set, just leave. A
825 * timeout is scheduled anyhow.
826 */
827 if (td->td_flags & TDF_TIMEOUT)
828 return;
829
830 CTR3(KTR_PROC, "sleepq_abort: thread %p (pid %ld, %s)",
831 (void *)td, (long)td->td_proc->p_pid, (void *)td->td_proc->p_comm);
832 wchan = td->td_wchan;
833 mtx_unlock_spin(&sched_lock);
834 sleepq_remove(td, wchan);
835 mtx_lock_spin(&sched_lock);
836}
| 697 ("%s: mismatch between sleep/wakeup and cv_*", __func__));
698 /* XXX: Do for all sleep queues eventually. */
699 if (flags & SLEEPQ_CONDVAR)
700 mtx_assert(sq->sq_lock, MA_OWNED);
701
702 /* Move blocked threads from the sleep queue to a temporary list. */
703 TAILQ_INIT(&list);
704 while (!TAILQ_EMPTY(&sq->sq_blocked)) {
705 td = TAILQ_FIRST(&sq->sq_blocked);
706 sleepq_remove_thread(sq, td);
707 TAILQ_INSERT_TAIL(&list, td, td_slpq);
708 }
709 sleepq_release(wchan);
710
711 /* Resume all the threads on the temporary list. */
712 while (!TAILQ_EMPTY(&list)) {
713 td = TAILQ_FIRST(&list);
714 TAILQ_REMOVE(&list, td, td_slpq);
715 sleepq_resume_thread(td, pri);
716 }
717}
718
719/*
720 * Time sleeping threads out. When the timeout expires, the thread is
721 * removed from the sleep queue and made runnable if it is still asleep.
722 */
723static void
724sleepq_timeout(void *arg)
725{
726 struct sleepqueue *sq;
727 struct thread *td;
728 void *wchan;
729
730 td = arg;
731 CTR3(KTR_PROC, "sleepq_timeout: thread %p (pid %ld, %s)",
732 (void *)td, (long)td->td_proc->p_pid, (void *)td->td_proc->p_comm);
733
734 /*
735 * First, see if the thread is asleep and get the wait channel if
736 * it is.
737 */
738 mtx_lock_spin(&sched_lock);
739 if (TD_ON_SLEEPQ(td)) {
740 wchan = td->td_wchan;
741 mtx_unlock_spin(&sched_lock);
742 sq = sleepq_lookup(wchan);
743 mtx_lock_spin(&sched_lock);
744 } else {
745 wchan = NULL;
746 sq = NULL;
747 }
748
749 /*
750 * At this point, if the thread is still on the sleep queue,
751 * we have that sleep queue locked as it cannot migrate sleep
752 * queues while we dropped sched_lock. If it had resumed and
753 * was on another CPU while the lock was dropped, it would have
754 * seen that TDF_TIMEOUT and TDF_TIMOFAIL are clear and the
755 * call to callout_stop() to stop this routine would have failed
756 * meaning that it would have already set TDF_TIMEOUT to
757 * synchronize with this function.
758 */
759 if (TD_ON_SLEEPQ(td)) {
760 MPASS(td->td_wchan == wchan);
761 MPASS(sq != NULL);
762 td->td_flags |= TDF_TIMEOUT;
763 mtx_unlock_spin(&sched_lock);
764 sleepq_remove_thread(sq, td);
765 sleepq_release(wchan);
766 sleepq_resume_thread(td, -1);
767 return;
768 } else if (wchan != NULL)
769 sleepq_release(wchan);
770
771 /*
772 * Now check for the edge cases. First, if TDF_TIMEOUT is set,
773 * then the other thread has already yielded to us, so clear
774 * the flag and resume it. If TDF_TIMEOUT is not set, then the
775 * we know that the other thread is not on a sleep queue, but it
776 * hasn't resumed execution yet. In that case, set TDF_TIMOFAIL
777 * to let it know that the timeout has already run and doesn't
778 * need to be canceled.
779 */
780 if (td->td_flags & TDF_TIMEOUT) {
781 MPASS(TD_IS_SLEEPING(td));
782 td->td_flags &= ~TDF_TIMEOUT;
783 TD_CLR_SLEEPING(td);
784 setrunnable(td);
785 } else
786 td->td_flags |= TDF_TIMOFAIL;
787 mtx_unlock_spin(&sched_lock);
788}
789
790/*
791 * Resumes a specific thread from the sleep queue associated with a specific
792 * wait channel if it is on that queue.
793 */
794void
795sleepq_remove(struct thread *td, void *wchan)
796{
797 struct sleepqueue *sq;
798
799 /*
800 * Look up the sleep queue for this wait channel, then re-check
801 * that the thread is asleep on that channel, if it is not, then
802 * bail.
803 */
804 MPASS(wchan != NULL);
805 sq = sleepq_lookup(wchan);
806 mtx_lock_spin(&sched_lock);
807 if (!TD_ON_SLEEPQ(td) || td->td_wchan != wchan) {
808 mtx_unlock_spin(&sched_lock);
809 sleepq_release(wchan);
810 return;
811 }
812 mtx_unlock_spin(&sched_lock);
813 MPASS(sq != NULL);
814
815 /* Thread is asleep on sleep queue sq, so wake it up. */
816 sleepq_remove_thread(sq, td);
817 sleepq_release(wchan);
818 sleepq_resume_thread(td, -1);
819}
820
821/*
822 * Abort a thread as if an interrupt had occurred. Only abort
823 * interruptible waits (unfortunately it isn't safe to abort others).
824 *
825 * XXX: What in the world does the comment below mean?
826 * Also, whatever the signal code does...
827 */
828void
829sleepq_abort(struct thread *td)
830{
831 void *wchan;
832
833 mtx_assert(&sched_lock, MA_OWNED);
834 MPASS(TD_ON_SLEEPQ(td));
835 MPASS(td->td_flags & TDF_SINTR);
836
837 /*
838 * If the TDF_TIMEOUT flag is set, just leave. A
839 * timeout is scheduled anyhow.
840 */
841 if (td->td_flags & TDF_TIMEOUT)
842 return;
843
844 CTR3(KTR_PROC, "sleepq_abort: thread %p (pid %ld, %s)",
845 (void *)td, (long)td->td_proc->p_pid, (void *)td->td_proc->p_comm);
846 wchan = td->td_wchan;
847 mtx_unlock_spin(&sched_lock);
848 sleepq_remove(td, wchan);
849 mtx_lock_spin(&sched_lock);
850}
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