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