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 2017 RackTop Systems.
29 * Copyright 2018, Joyent, Inc.
30 */
31
32 #include <sys/taskq_impl.h>
33
34 #include <sys/class.h>
35 #include <sys/debug.h>
36 #include <sys/ksynch.h>
37 #include <sys/kmem.h>
38 #include <sys/time.h>
39 #include <sys/systm.h>
40 #include <sys/sysmacros.h>
41 #include <sys/unistd.h>
42
43 /* avoid <sys/disp.h> */
44 #define maxclsyspri 99
45
46 /* avoid <unistd.h> */
47 extern long sysconf(int);
48
49 /* avoiding <thread.h> */
50 typedef unsigned int thread_t;
51 typedef unsigned int thread_key_t;
52
53 extern int thr_create(void *, size_t, void *(*)(void *), void *, long,
54 thread_t *);
55 extern int thr_join(thread_t, thread_t *, void **);
56
57 /*
58 * POSIX.1c Note:
59 * THR_BOUND is defined same as PTHREAD_SCOPE_SYSTEM in <pthread.h>
60 * THR_DETACHED is defined same as PTHREAD_CREATE_DETACHED in <pthread.h>
61 * Any changes in these definitions should be reflected in <pthread.h>
62 */
63 #define THR_BOUND 0x00000001 /* = PTHREAD_SCOPE_SYSTEM */
64 #define THR_NEW_LWP 0x00000002
65 #define THR_DETACHED 0x00000040 /* = PTHREAD_CREATE_DETACHED */
66 #define THR_SUSPENDED 0x00000080
67 #define THR_DAEMON 0x00000100
68
69
70 int taskq_now;
71 taskq_t *system_taskq;
72
73 #define TASKQ_ACTIVE 0x00010000
74
75 struct taskq {
76 kmutex_t tq_lock;
77 krwlock_t tq_threadlock;
78 kcondvar_t tq_dispatch_cv;
79 kcondvar_t tq_wait_cv;
80 thread_t *tq_threadlist;
81 int tq_flags;
82 int tq_active;
83 int tq_nthreads;
84 int tq_nalloc;
85 int tq_minalloc;
86 int tq_maxalloc;
87 kcondvar_t tq_maxalloc_cv;
88 int tq_maxalloc_wait;
89 taskq_ent_t *tq_freelist;
90 taskq_ent_t tq_task;
91 };
92
93 static taskq_ent_t *
94 task_alloc(taskq_t *tq, int tqflags)
95 {
96 taskq_ent_t *t;
97 int rv;
98
99 again: if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) {
100 tq->tq_freelist = t->tqent_next;
101 } else {
102 if (tq->tq_nalloc >= tq->tq_maxalloc) {
103 if (!(tqflags & KM_SLEEP))
104 return (NULL);
105
106 /*
107 * We don't want to exceed tq_maxalloc, but we can't
108 * wait for other tasks to complete (and thus free up
109 * task structures) without risking deadlock with
110 * the caller. So, we just delay for one second
111 * to throttle the allocation rate. If we have tasks
112 * complete before one second timeout expires then
113 * taskq_ent_free will signal us and we will
114 * immediately retry the allocation.
115 */
116 tq->tq_maxalloc_wait++;
117 rv = cv_timedwait(&tq->tq_maxalloc_cv,
118 &tq->tq_lock, ddi_get_lbolt() + hz);
119 tq->tq_maxalloc_wait--;
120 if (rv > 0)
121 goto again; /* signaled */
122 }
123 mutex_exit(&tq->tq_lock);
124
125 t = kmem_alloc(sizeof (taskq_ent_t), tqflags);
126
127 mutex_enter(&tq->tq_lock);
128 if (t != NULL)
129 tq->tq_nalloc++;
130 }
131 return (t);
132 }
133
134 static void
135 task_free(taskq_t *tq, taskq_ent_t *t)
136 {
137 if (tq->tq_nalloc <= tq->tq_minalloc) {
138 t->tqent_next = tq->tq_freelist;
139 tq->tq_freelist = t;
140 } else {
141 tq->tq_nalloc--;
142 mutex_exit(&tq->tq_lock);
143 kmem_free(t, sizeof (taskq_ent_t));
144 mutex_enter(&tq->tq_lock);
145 }
146
147 if (tq->tq_maxalloc_wait)
148 cv_signal(&tq->tq_maxalloc_cv);
149 }
150
151 taskqid_t
152 taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags)
153 {
154 taskq_ent_t *t;
155
156 if (taskq_now) {
157 func(arg);
158 return (1);
159 }
160
161 mutex_enter(&tq->tq_lock);
162 ASSERT(tq->tq_flags & TASKQ_ACTIVE);
163 if ((t = task_alloc(tq, tqflags)) == NULL) {
164 mutex_exit(&tq->tq_lock);
165 return (0);
166 }
167 if (tqflags & TQ_FRONT) {
168 t->tqent_next = tq->tq_task.tqent_next;
169 t->tqent_prev = &tq->tq_task;
170 } else {
171 t->tqent_next = &tq->tq_task;
172 t->tqent_prev = tq->tq_task.tqent_prev;
173 }
174 t->tqent_next->tqent_prev = t;
175 t->tqent_prev->tqent_next = t;
176 t->tqent_func = func;
177 t->tqent_arg = arg;
178 t->tqent_flags = 0;
179 cv_signal(&tq->tq_dispatch_cv);
180 mutex_exit(&tq->tq_lock);
181 return (1);
182 }
183
184 void
185 taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
186 taskq_ent_t *t)
187 {
188 ASSERT(func != NULL);
189 ASSERT(!(tq->tq_flags & TASKQ_DYNAMIC));
190
191 /*
192 * Mark it as a prealloc'd task. This is important
193 * to ensure that we don't free it later.
194 */
195 t->tqent_flags |= TQENT_FLAG_PREALLOC;
196 /*
197 * Enqueue the task to the underlying queue.
198 */
199 mutex_enter(&tq->tq_lock);
200
201 if (flags & TQ_FRONT) {
202 t->tqent_next = tq->tq_task.tqent_next;
203 t->tqent_prev = &tq->tq_task;
204 } else {
205 t->tqent_next = &tq->tq_task;
206 t->tqent_prev = tq->tq_task.tqent_prev;
207 }
208 t->tqent_next->tqent_prev = t;
209 t->tqent_prev->tqent_next = t;
210 t->tqent_func = func;
211 t->tqent_arg = arg;
212 cv_signal(&tq->tq_dispatch_cv);
213 mutex_exit(&tq->tq_lock);
214 }
215
216 boolean_t
217 taskq_empty(taskq_t *tq)
218 {
219 boolean_t rv;
220
221 mutex_enter(&tq->tq_lock);
222 rv = (tq->tq_task.tqent_next == &tq->tq_task) && (tq->tq_active == 0);
223 mutex_exit(&tq->tq_lock);
224
225 return (rv);
226 }
227
228 void
229 taskq_wait(taskq_t *tq)
230 {
231 mutex_enter(&tq->tq_lock);
232 while (tq->tq_task.tqent_next != &tq->tq_task || tq->tq_active != 0)
233 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
234 mutex_exit(&tq->tq_lock);
235 }
236
237 static void *
238 taskq_thread(void *arg)
239 {
240 taskq_t *tq = arg;
241 taskq_ent_t *t;
242 boolean_t prealloc;
243
244 mutex_enter(&tq->tq_lock);
245 while (tq->tq_flags & TASKQ_ACTIVE) {
246 if ((t = tq->tq_task.tqent_next) == &tq->tq_task) {
247 if (--tq->tq_active == 0)
248 cv_broadcast(&tq->tq_wait_cv);
249 cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock);
250 tq->tq_active++;
251 continue;
252 }
253 t->tqent_prev->tqent_next = t->tqent_next;
254 t->tqent_next->tqent_prev = t->tqent_prev;
255 t->tqent_next = NULL;
256 t->tqent_prev = NULL;
257 prealloc = t->tqent_flags & TQENT_FLAG_PREALLOC;
258 mutex_exit(&tq->tq_lock);
259
260 rw_enter(&tq->tq_threadlock, RW_READER);
261 t->tqent_func(t->tqent_arg);
262 rw_exit(&tq->tq_threadlock);
263
264 mutex_enter(&tq->tq_lock);
265 if (!prealloc)
266 task_free(tq, t);
267 }
268 tq->tq_nthreads--;
269 cv_broadcast(&tq->tq_wait_cv);
270 mutex_exit(&tq->tq_lock);
271 return (NULL);
272 }
273
274 /*ARGSUSED*/
275 taskq_t *
276 taskq_create(const char *name, int nthr, pri_t pri, int minalloc,
277 int maxalloc, uint_t flags)
278 {
279 return (taskq_create_proc(name, nthr, pri,
280 minalloc, maxalloc, NULL, flags));
281 }
282
283 /*ARGSUSED*/
284 taskq_t *
285 taskq_create_sysdc(const char *name, int nthr, int minalloc,
286 int maxalloc, proc_t *proc, uint_t dc, uint_t flags)
287 {
288 return (taskq_create_proc(name, nthr, maxclsyspri,
289 minalloc, maxalloc, proc, flags));
290 }
291
292 /*ARGSUSED*/
293 taskq_t *
294 taskq_create_proc(const char *name, int nthreads, pri_t pri,
295 int minalloc, int maxalloc, proc_t *proc, uint_t flags)
296 {
297 taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP);
298 int t;
299
300 if (flags & TASKQ_THREADS_CPU_PCT) {
301 int pct;
302 ASSERT3S(nthreads, >=, 0);
303 ASSERT3S(nthreads, <=, 100);
304 pct = MIN(nthreads, 100);
305 pct = MAX(pct, 0);
306
307 nthreads = (sysconf(_SC_NPROCESSORS_ONLN) * pct) / 100;
308 nthreads = MAX(nthreads, 1); /* need at least 1 thread */
309 } else {
310 ASSERT3S(nthreads, >=, 1);
311 }
312
313 rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL);
314 mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL);
315 cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL);
316 cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL);
317 cv_init(&tq->tq_maxalloc_cv, NULL, CV_DEFAULT, NULL);
318 tq->tq_flags = flags | TASKQ_ACTIVE;
319 tq->tq_active = nthreads;
320 tq->tq_nthreads = nthreads;
321 tq->tq_minalloc = minalloc;
322 tq->tq_maxalloc = maxalloc;
323 tq->tq_task.tqent_next = &tq->tq_task;
324 tq->tq_task.tqent_prev = &tq->tq_task;
325 tq->tq_threadlist = kmem_alloc(nthreads * sizeof (thread_t), KM_SLEEP);
326
327 if (flags & TASKQ_PREPOPULATE) {
328 mutex_enter(&tq->tq_lock);
329 while (minalloc-- > 0)
330 task_free(tq, task_alloc(tq, KM_SLEEP));
331 mutex_exit(&tq->tq_lock);
332 }
333
334 for (t = 0; t < nthreads; t++)
335 (void) thr_create(0, 0, taskq_thread,
336 tq, THR_BOUND, &tq->tq_threadlist[t]);
337
338 return (tq);
339 }
340
341 void
342 taskq_destroy(taskq_t *tq)
343 {
344 int t;
345 int nthreads = tq->tq_nthreads;
346
347 taskq_wait(tq);
348
349 mutex_enter(&tq->tq_lock);
350
351 tq->tq_flags &= ~TASKQ_ACTIVE;
352 cv_broadcast(&tq->tq_dispatch_cv);
353
354 while (tq->tq_nthreads != 0)
355 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
356
357 tq->tq_minalloc = 0;
358 while (tq->tq_nalloc != 0) {
359 ASSERT(tq->tq_freelist != NULL);
360 task_free(tq, task_alloc(tq, KM_SLEEP));
361 }
362
363 mutex_exit(&tq->tq_lock);
364
365 for (t = 0; t < nthreads; t++)
366 (void) thr_join(tq->tq_threadlist[t], NULL, NULL);
367
368 kmem_free(tq->tq_threadlist, nthreads * sizeof (thread_t));
369
370 rw_destroy(&tq->tq_threadlock);
371 mutex_destroy(&tq->tq_lock);
372 cv_destroy(&tq->tq_dispatch_cv);
373 cv_destroy(&tq->tq_wait_cv);
374 cv_destroy(&tq->tq_maxalloc_cv);
375
376 kmem_free(tq, sizeof (taskq_t));
377 }
378
379 int
380 taskq_member(taskq_t *tq, struct _kthread *t)
381 {
382 int i;
383
384 if (taskq_now)
385 return (1);
386
387 for (i = 0; i < tq->tq_nthreads; i++)
388 if (tq->tq_threadlist[i] == (thread_t)(uintptr_t)t)
389 return (1);
390
391 return (0);
392 }
393
394 void
395 system_taskq_init(void)
396 {
397 system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512,
398 TASKQ_DYNAMIC | TASKQ_PREPOPULATE);
399 }
400
401 void
402 system_taskq_fini(void)
403 {
404 taskq_destroy(system_taskq);
405 system_taskq = NULL; /* defensive */
406 }