1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2010 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25 /*
26 * Copyright 2012 Garrett D'Amore <garrett@damore.org>. All rights reserved.
27 * Copyright 2013 Nexenta Systems, Inc. All rights reserved.
28 * Copyright (c) 2017, Joyent, Inc.
29 */
30
31 #include <sys/taskq_impl.h>
32
33 #include <sys/class.h>
34 #include <sys/debug.h>
35 #include <sys/ksynch.h>
36 #include <sys/kmem.h>
37 #include <sys/time.h>
38 #include <sys/systm.h>
39 #include <sys/sysmacros.h>
40 #include <sys/unistd.h>
41
42 /* avoid <unistd.h> */
43 extern long sysconf(int);
44
45 /* avoiding <thread.h> */
46 typedef unsigned int thread_t;
47 typedef unsigned int thread_key_t;
48
49 extern int thr_create(void *, size_t, void *(*)(void *), void *, long,
50 thread_t *);
51 extern int thr_join(thread_t, thread_t *, void **);
52
53 /*
54 * POSIX.1c Note:
55 * THR_BOUND is defined same as PTHREAD_SCOPE_SYSTEM in <pthread.h>
56 * THR_DETACHED is defined same as PTHREAD_CREATE_DETACHED in <pthread.h>
57 * Any changes in these definitions should be reflected in <pthread.h>
58 */
59 #define THR_BOUND 0x00000001 /* = PTHREAD_SCOPE_SYSTEM */
60 #define THR_NEW_LWP 0x00000002
61 #define THR_DETACHED 0x00000040 /* = PTHREAD_CREATE_DETACHED */
62 #define THR_SUSPENDED 0x00000080
63 #define THR_DAEMON 0x00000100
64
65
66 int taskq_now;
67 taskq_t *system_taskq;
68
69 #define TASKQ_ACTIVE 0x00010000
70
71 struct taskq {
72 kmutex_t tq_lock;
73 krwlock_t tq_threadlock;
74 kcondvar_t tq_dispatch_cv;
75 kcondvar_t tq_wait_cv;
76 thread_t *tq_threadlist;
77 int tq_flags;
78 int tq_active;
79 int tq_nthreads;
80 int tq_nalloc;
81 int tq_minalloc;
82 int tq_maxalloc;
83 kcondvar_t tq_maxalloc_cv;
84 int tq_maxalloc_wait;
85 taskq_ent_t *tq_freelist;
86 taskq_ent_t tq_task;
87 };
88
89 static taskq_ent_t *
90 task_alloc(taskq_t *tq, int tqflags)
91 {
92 taskq_ent_t *t;
93 int rv;
94
95 again: if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) {
96 tq->tq_freelist = t->tqent_next;
97 } else {
98 if (tq->tq_nalloc >= tq->tq_maxalloc) {
99 if (!(tqflags & KM_SLEEP))
100 return (NULL);
101
102 /*
103 * We don't want to exceed tq_maxalloc, but we can't
104 * wait for other tasks to complete (and thus free up
105 * task structures) without risking deadlock with
106 * the caller. So, we just delay for one second
107 * to throttle the allocation rate. If we have tasks
108 * complete before one second timeout expires then
109 * taskq_ent_free will signal us and we will
110 * immediately retry the allocation.
111 */
112 tq->tq_maxalloc_wait++;
113 rv = cv_timedwait(&tq->tq_maxalloc_cv,
114 &tq->tq_lock, ddi_get_lbolt() + hz);
115 tq->tq_maxalloc_wait--;
116 if (rv > 0)
117 goto again; /* signaled */
118 }
119 mutex_exit(&tq->tq_lock);
120
121 t = kmem_alloc(sizeof (taskq_ent_t), tqflags);
122
123 mutex_enter(&tq->tq_lock);
124 if (t != NULL)
125 tq->tq_nalloc++;
126 }
127 return (t);
128 }
129
130 static void
131 task_free(taskq_t *tq, taskq_ent_t *t)
132 {
133 if (tq->tq_nalloc <= tq->tq_minalloc) {
134 t->tqent_next = tq->tq_freelist;
135 tq->tq_freelist = t;
136 } else {
137 tq->tq_nalloc--;
138 mutex_exit(&tq->tq_lock);
139 kmem_free(t, sizeof (taskq_ent_t));
140 mutex_enter(&tq->tq_lock);
141 }
142
143 if (tq->tq_maxalloc_wait)
144 cv_signal(&tq->tq_maxalloc_cv);
145 }
146
147 taskqid_t
148 taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags)
149 {
150 taskq_ent_t *t;
151
152 if (taskq_now) {
153 func(arg);
154 return (1);
155 }
156
157 mutex_enter(&tq->tq_lock);
158 ASSERT(tq->tq_flags & TASKQ_ACTIVE);
159 if ((t = task_alloc(tq, tqflags)) == NULL) {
160 mutex_exit(&tq->tq_lock);
161 return (0);
162 }
163 if (tqflags & TQ_FRONT) {
164 t->tqent_next = tq->tq_task.tqent_next;
165 t->tqent_prev = &tq->tq_task;
166 } else {
167 t->tqent_next = &tq->tq_task;
168 t->tqent_prev = tq->tq_task.tqent_prev;
169 }
170 t->tqent_next->tqent_prev = t;
171 t->tqent_prev->tqent_next = t;
172 t->tqent_func = func;
173 t->tqent_arg = arg;
174 t->tqent_flags = 0;
175 cv_signal(&tq->tq_dispatch_cv);
176 mutex_exit(&tq->tq_lock);
177 return (1);
178 }
179
180 void
181 taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
182 taskq_ent_t *t)
183 {
184 ASSERT(func != NULL);
185 ASSERT(!(tq->tq_flags & TASKQ_DYNAMIC));
186
187 /*
188 * Mark it as a prealloc'd task. This is important
189 * to ensure that we don't free it later.
190 */
191 t->tqent_flags |= TQENT_FLAG_PREALLOC;
192 /*
193 * Enqueue the task to the underlying queue.
194 */
195 mutex_enter(&tq->tq_lock);
196
197 if (flags & TQ_FRONT) {
198 t->tqent_next = tq->tq_task.tqent_next;
199 t->tqent_prev = &tq->tq_task;
200 } else {
201 t->tqent_next = &tq->tq_task;
202 t->tqent_prev = tq->tq_task.tqent_prev;
203 }
204 t->tqent_next->tqent_prev = t;
205 t->tqent_prev->tqent_next = t;
206 t->tqent_func = func;
207 t->tqent_arg = arg;
208 cv_signal(&tq->tq_dispatch_cv);
209 mutex_exit(&tq->tq_lock);
210 }
211
212 boolean_t
213 taskq_empty(taskq_t *tq)
214 {
215 boolean_t rv;
216
217 mutex_enter(&tq->tq_lock);
218 rv = (tq->tq_task.tqent_next == &tq->tq_task) && (tq->tq_active == 0);
219 mutex_exit(&tq->tq_lock);
220
221 return (rv);
222 }
223
224 void
225 taskq_wait(taskq_t *tq)
226 {
227 mutex_enter(&tq->tq_lock);
228 while (tq->tq_task.tqent_next != &tq->tq_task || tq->tq_active != 0)
229 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
230 mutex_exit(&tq->tq_lock);
231 }
232
233 static void *
234 taskq_thread(void *arg)
235 {
236 taskq_t *tq = arg;
237 taskq_ent_t *t;
238 boolean_t prealloc;
239
240 mutex_enter(&tq->tq_lock);
241 while (tq->tq_flags & TASKQ_ACTIVE) {
242 if ((t = tq->tq_task.tqent_next) == &tq->tq_task) {
243 if (--tq->tq_active == 0)
244 cv_broadcast(&tq->tq_wait_cv);
245 cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock);
246 tq->tq_active++;
247 continue;
248 }
249 t->tqent_prev->tqent_next = t->tqent_next;
250 t->tqent_next->tqent_prev = t->tqent_prev;
251 t->tqent_next = NULL;
252 t->tqent_prev = NULL;
253 prealloc = t->tqent_flags & TQENT_FLAG_PREALLOC;
254 mutex_exit(&tq->tq_lock);
255
256 rw_enter(&tq->tq_threadlock, RW_READER);
257 t->tqent_func(t->tqent_arg);
258 rw_exit(&tq->tq_threadlock);
259
260 mutex_enter(&tq->tq_lock);
261 if (!prealloc)
262 task_free(tq, t);
263 }
264 tq->tq_nthreads--;
265 cv_broadcast(&tq->tq_wait_cv);
266 mutex_exit(&tq->tq_lock);
267 return (NULL);
268 }
269
270 /*ARGSUSED*/
271 taskq_t *
272 taskq_create(const char *name, int nthr, pri_t pri, int minalloc,
273 int maxalloc, uint_t flags)
274 {
275 return (taskq_create_proc(name, nthr, pri,
276 minalloc, maxalloc, NULL, flags));
277 }
278
279 /*ARGSUSED*/
280 taskq_t *
281 taskq_create_proc(const char *name, int nthreads, pri_t pri,
282 int minalloc, int maxalloc, proc_t *proc, uint_t flags)
283 {
284 taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP);
285 int t;
286
287 if (flags & TASKQ_THREADS_CPU_PCT) {
288 int pct;
289 ASSERT3S(nthreads, >=, 0);
290 ASSERT3S(nthreads, <=, 100);
291 pct = MIN(nthreads, 100);
292 pct = MAX(pct, 0);
293
294 nthreads = (sysconf(_SC_NPROCESSORS_ONLN) * pct) / 100;
295 nthreads = MAX(nthreads, 1); /* need at least 1 thread */
296 } else {
297 ASSERT3S(nthreads, >=, 1);
298 }
299
300 rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL);
301 mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL);
302 cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL);
303 cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL);
304 cv_init(&tq->tq_maxalloc_cv, NULL, CV_DEFAULT, NULL);
305 tq->tq_flags = flags | TASKQ_ACTIVE;
306 tq->tq_active = nthreads;
307 tq->tq_nthreads = nthreads;
308 tq->tq_minalloc = minalloc;
309 tq->tq_maxalloc = maxalloc;
310 tq->tq_task.tqent_next = &tq->tq_task;
311 tq->tq_task.tqent_prev = &tq->tq_task;
312 tq->tq_threadlist = kmem_alloc(nthreads * sizeof (thread_t), KM_SLEEP);
313
314 if (flags & TASKQ_PREPOPULATE) {
315 mutex_enter(&tq->tq_lock);
316 while (minalloc-- > 0)
317 task_free(tq, task_alloc(tq, KM_SLEEP));
318 mutex_exit(&tq->tq_lock);
319 }
320
321 for (t = 0; t < nthreads; t++)
322 (void) thr_create(0, 0, taskq_thread,
323 tq, THR_BOUND, &tq->tq_threadlist[t]);
324
325 return (tq);
326 }
327
328 void
329 taskq_destroy(taskq_t *tq)
330 {
331 int t;
332 int nthreads = tq->tq_nthreads;
333
334 taskq_wait(tq);
335
336 mutex_enter(&tq->tq_lock);
337
338 tq->tq_flags &= ~TASKQ_ACTIVE;
339 cv_broadcast(&tq->tq_dispatch_cv);
340
341 while (tq->tq_nthreads != 0)
342 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
343
344 tq->tq_minalloc = 0;
345 while (tq->tq_nalloc != 0) {
346 ASSERT(tq->tq_freelist != NULL);
347 task_free(tq, task_alloc(tq, KM_SLEEP));
348 }
349
350 mutex_exit(&tq->tq_lock);
351
352 for (t = 0; t < nthreads; t++)
353 (void) thr_join(tq->tq_threadlist[t], NULL, NULL);
354
355 kmem_free(tq->tq_threadlist, nthreads * sizeof (thread_t));
356
357 rw_destroy(&tq->tq_threadlock);
358 mutex_destroy(&tq->tq_lock);
359 cv_destroy(&tq->tq_dispatch_cv);
360 cv_destroy(&tq->tq_wait_cv);
361 cv_destroy(&tq->tq_maxalloc_cv);
362
363 kmem_free(tq, sizeof (taskq_t));
364 }
365
366 int
367 taskq_member(taskq_t *tq, struct _kthread *t)
368 {
369 int i;
370
371 if (taskq_now)
372 return (1);
373
374 for (i = 0; i < tq->tq_nthreads; i++)
375 if (tq->tq_threadlist[i] == (thread_t)(uintptr_t)t)
376 return (1);
377
378 return (0);
379 }
380
381 void
382 system_taskq_init(void)
383 {
384 system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512,
385 TASKQ_DYNAMIC | TASKQ_PREPOPULATE);
386 }
387
388 void
389 system_taskq_fini(void)
390 {
391 taskq_destroy(system_taskq);
392 system_taskq = NULL; /* defensive */
393 }