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 */
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 <sys/disp.h> */
43 #define maxclsyspri 99
44
45 /* avoid <unistd.h> */
46 extern long sysconf(int);
47
48 /* avoiding <thread.h> */
49 typedef unsigned int thread_t;
50 typedef unsigned int thread_key_t;
51
52 extern int thr_create(void *, size_t, void *(*)(void *), void *, long,
53 thread_t *);
54 extern int thr_join(thread_t, thread_t *, void **);
55
56 /*
57 * POSIX.1c Note:
58 * THR_BOUND is defined same as PTHREAD_SCOPE_SYSTEM in <pthread.h>
59 * THR_DETACHED is defined same as PTHREAD_CREATE_DETACHED in <pthread.h>
60 * Any changes in these definitions should be reflected in <pthread.h>
61 */
62 #define THR_BOUND 0x00000001 /* = PTHREAD_SCOPE_SYSTEM */
63 #define THR_NEW_LWP 0x00000002
64 #define THR_DETACHED 0x00000040 /* = PTHREAD_CREATE_DETACHED */
65 #define THR_SUSPENDED 0x00000080
66 #define THR_DAEMON 0x00000100
67
68
69 int taskq_now;
70 taskq_t *system_taskq;
71
72 #define TASKQ_ACTIVE 0x00010000
73
74 struct taskq {
75 kmutex_t tq_lock;
76 krwlock_t tq_threadlock;
77 kcondvar_t tq_dispatch_cv;
78 kcondvar_t tq_wait_cv;
79 thread_t *tq_threadlist;
80 int tq_flags;
81 int tq_active;
82 int tq_nthreads;
83 int tq_nalloc;
84 int tq_minalloc;
85 int tq_maxalloc;
86 kcondvar_t tq_maxalloc_cv;
87 int tq_maxalloc_wait;
88 taskq_ent_t *tq_freelist;
89 taskq_ent_t tq_task;
90 };
91
92 static taskq_ent_t *
93 task_alloc(taskq_t *tq, int tqflags)
94 {
95 taskq_ent_t *t;
96 int rv;
97
98 again: if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) {
99 tq->tq_freelist = t->tqent_next;
100 } else {
101 if (tq->tq_nalloc >= tq->tq_maxalloc) {
102 if (!(tqflags & KM_SLEEP))
103 return (NULL);
104
105 /*
106 * We don't want to exceed tq_maxalloc, but we can't
107 * wait for other tasks to complete (and thus free up
108 * task structures) without risking deadlock with
109 * the caller. So, we just delay for one second
110 * to throttle the allocation rate. If we have tasks
111 * complete before one second timeout expires then
112 * taskq_ent_free will signal us and we will
113 * immediately retry the allocation.
114 */
115 tq->tq_maxalloc_wait++;
116 rv = cv_timedwait(&tq->tq_maxalloc_cv,
117 &tq->tq_lock, ddi_get_lbolt() + hz);
118 tq->tq_maxalloc_wait--;
119 if (rv > 0)
120 goto again; /* signaled */
121 }
122 mutex_exit(&tq->tq_lock);
123
124 t = kmem_alloc(sizeof (taskq_ent_t), tqflags);
125
126 mutex_enter(&tq->tq_lock);
127 if (t != NULL)
128 tq->tq_nalloc++;
129 }
130 return (t);
131 }
132
133 static void
134 task_free(taskq_t *tq, taskq_ent_t *t)
135 {
136 if (tq->tq_nalloc <= tq->tq_minalloc) {
137 t->tqent_next = tq->tq_freelist;
138 tq->tq_freelist = t;
139 } else {
140 tq->tq_nalloc--;
141 mutex_exit(&tq->tq_lock);
142 kmem_free(t, sizeof (taskq_ent_t));
143 mutex_enter(&tq->tq_lock);
144 }
145
146 if (tq->tq_maxalloc_wait)
147 cv_signal(&tq->tq_maxalloc_cv);
148 }
149
150 taskqid_t
151 taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags)
152 {
153 taskq_ent_t *t;
154
155 if (taskq_now) {
156 func(arg);
157 return (1);
158 }
159
160 mutex_enter(&tq->tq_lock);
161 ASSERT(tq->tq_flags & TASKQ_ACTIVE);
162 if ((t = task_alloc(tq, tqflags)) == NULL) {
163 mutex_exit(&tq->tq_lock);
164 return (0);
165 }
166 if (tqflags & TQ_FRONT) {
167 t->tqent_next = tq->tq_task.tqent_next;
168 t->tqent_prev = &tq->tq_task;
169 } else {
170 t->tqent_next = &tq->tq_task;
171 t->tqent_prev = tq->tq_task.tqent_prev;
172 }
173 t->tqent_next->tqent_prev = t;
174 t->tqent_prev->tqent_next = t;
175 t->tqent_func = func;
176 t->tqent_arg = arg;
177 t->tqent_flags = 0;
178 cv_signal(&tq->tq_dispatch_cv);
179 mutex_exit(&tq->tq_lock);
180 return (1);
181 }
182
183 void
184 taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
185 taskq_ent_t *t)
186 {
187 ASSERT(func != NULL);
188 ASSERT(!(tq->tq_flags & TASKQ_DYNAMIC));
189
190 /*
191 * Mark it as a prealloc'd task. This is important
192 * to ensure that we don't free it later.
193 */
194 t->tqent_flags |= TQENT_FLAG_PREALLOC;
195 /*
196 * Enqueue the task to the underlying queue.
197 */
198 mutex_enter(&tq->tq_lock);
199
200 if (flags & TQ_FRONT) {
201 t->tqent_next = tq->tq_task.tqent_next;
202 t->tqent_prev = &tq->tq_task;
203 } else {
204 t->tqent_next = &tq->tq_task;
205 t->tqent_prev = tq->tq_task.tqent_prev;
206 }
207 t->tqent_next->tqent_prev = t;
208 t->tqent_prev->tqent_next = t;
209 t->tqent_func = func;
210 t->tqent_arg = arg;
211 cv_signal(&tq->tq_dispatch_cv);
212 mutex_exit(&tq->tq_lock);
213 }
214
215 void
216 taskq_wait(taskq_t *tq)
217 {
218 mutex_enter(&tq->tq_lock);
219 while (tq->tq_task.tqent_next != &tq->tq_task || tq->tq_active != 0)
220 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
221 mutex_exit(&tq->tq_lock);
222 }
223
224 static void *
225 taskq_thread(void *arg)
226 {
227 taskq_t *tq = arg;
228 taskq_ent_t *t;
229 boolean_t prealloc;
230
231 mutex_enter(&tq->tq_lock);
232 while (tq->tq_flags & TASKQ_ACTIVE) {
233 if ((t = tq->tq_task.tqent_next) == &tq->tq_task) {
234 if (--tq->tq_active == 0)
235 cv_broadcast(&tq->tq_wait_cv);
236 cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock);
237 tq->tq_active++;
238 continue;
239 }
240 t->tqent_prev->tqent_next = t->tqent_next;
241 t->tqent_next->tqent_prev = t->tqent_prev;
242 t->tqent_next = NULL;
243 t->tqent_prev = NULL;
244 prealloc = t->tqent_flags & TQENT_FLAG_PREALLOC;
245 mutex_exit(&tq->tq_lock);
246
247 rw_enter(&tq->tq_threadlock, RW_READER);
248 t->tqent_func(t->tqent_arg);
249 rw_exit(&tq->tq_threadlock);
250
251 mutex_enter(&tq->tq_lock);
252 if (!prealloc)
253 task_free(tq, t);
254 }
255 tq->tq_nthreads--;
256 cv_broadcast(&tq->tq_wait_cv);
257 mutex_exit(&tq->tq_lock);
258 return (NULL);
259 }
260
261 /*ARGSUSED*/
262 taskq_t *
263 taskq_create(const char *name, int nthr, pri_t pri, int minalloc,
264 int maxalloc, uint_t flags)
265 {
266 return (taskq_create_proc(name, nthr, pri,
267 minalloc, maxalloc, NULL, flags));
268 }
269
270 /*ARGSUSED*/
271 taskq_t *
272 taskq_create_sysdc(const char *name, int nthr, int minalloc,
273 int maxalloc, proc_t *proc, uint_t dc, uint_t flags)
274 {
275 return (taskq_create_proc(name, nthr, maxclsyspri,
276 minalloc, maxalloc, proc, 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 }