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 *
task_alloc(taskq_t * tq,int tqflags)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_NOSLEEP)
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
task_free(taskq_t * tq,taskq_ent_t * t)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
taskq_dispatch(taskq_t * tq,task_func_t func,void * arg,uint_t tqflags)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 (TASKQID_INVALID);
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
taskq_dispatch_ent(taskq_t * tq,task_func_t func,void * arg,uint_t flags,taskq_ent_t * t)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
taskq_empty(taskq_t * tq)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
taskq_wait(taskq_t * tq)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 void
taskq_wait_id(taskq_t * tq,taskqid_t id __unused)238 taskq_wait_id(taskq_t *tq, taskqid_t id __unused)
239 {
240 taskq_wait(tq);
241 }
242
243 static void *
taskq_thread(void * arg)244 taskq_thread(void *arg)
245 {
246 taskq_t *tq = arg;
247 taskq_ent_t *t;
248 boolean_t prealloc;
249
250 mutex_enter(&tq->tq_lock);
251 while (tq->tq_flags & TASKQ_ACTIVE) {
252 if ((t = tq->tq_task.tqent_next) == &tq->tq_task) {
253 if (--tq->tq_active == 0)
254 cv_broadcast(&tq->tq_wait_cv);
255 cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock);
256 tq->tq_active++;
257 continue;
258 }
259 t->tqent_prev->tqent_next = t->tqent_next;
260 t->tqent_next->tqent_prev = t->tqent_prev;
261 t->tqent_next = NULL;
262 t->tqent_prev = NULL;
263 prealloc = t->tqent_flags & TQENT_FLAG_PREALLOC;
264 mutex_exit(&tq->tq_lock);
265
266 rw_enter(&tq->tq_threadlock, RW_READER);
267 t->tqent_func(t->tqent_arg);
268 rw_exit(&tq->tq_threadlock);
269
270 mutex_enter(&tq->tq_lock);
271 if (!prealloc)
272 task_free(tq, t);
273 }
274 tq->tq_nthreads--;
275 cv_broadcast(&tq->tq_wait_cv);
276 mutex_exit(&tq->tq_lock);
277 return (NULL);
278 }
279
280 /*ARGSUSED*/
281 taskq_t *
taskq_create(const char * name,int nthr,pri_t pri,int minalloc,int maxalloc,uint_t flags)282 taskq_create(const char *name, int nthr, pri_t pri, int minalloc,
283 int maxalloc, uint_t flags)
284 {
285 return (taskq_create_proc(name, nthr, pri,
286 minalloc, maxalloc, NULL, flags));
287 }
288
289 /*ARGSUSED*/
290 taskq_t *
taskq_create_sysdc(const char * name,int nthr,int minalloc,int maxalloc,proc_t * proc,uint_t dc,uint_t flags)291 taskq_create_sysdc(const char *name, int nthr, int minalloc,
292 int maxalloc, proc_t *proc, uint_t dc, uint_t flags)
293 {
294 return (taskq_create_proc(name, nthr, maxclsyspri,
295 minalloc, maxalloc, proc, flags));
296 }
297
298 /*ARGSUSED*/
299 taskq_t *
taskq_create_proc(const char * name,int nthreads,pri_t pri,int minalloc,int maxalloc,proc_t * proc,uint_t flags)300 taskq_create_proc(const char *name, int nthreads, pri_t pri,
301 int minalloc, int maxalloc, proc_t *proc, uint_t flags)
302 {
303 taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP);
304 int t;
305
306 if (flags & TASKQ_THREADS_CPU_PCT) {
307 int pct;
308 ASSERT3S(nthreads, >=, 0);
309 ASSERT3S(nthreads, <=, 100);
310 pct = MIN(nthreads, 100);
311 pct = MAX(pct, 0);
312
313 nthreads = (sysconf(_SC_NPROCESSORS_ONLN) * pct) / 100;
314 nthreads = MAX(nthreads, 1); /* need at least 1 thread */
315 } else {
316 ASSERT3S(nthreads, >=, 1);
317 }
318
319 rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL);
320 mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL);
321 cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL);
322 cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL);
323 cv_init(&tq->tq_maxalloc_cv, NULL, CV_DEFAULT, NULL);
324 tq->tq_flags = flags | TASKQ_ACTIVE;
325 tq->tq_active = nthreads;
326 tq->tq_nthreads = nthreads;
327 tq->tq_minalloc = minalloc;
328 tq->tq_maxalloc = maxalloc;
329 tq->tq_task.tqent_next = &tq->tq_task;
330 tq->tq_task.tqent_prev = &tq->tq_task;
331 tq->tq_threadlist = kmem_alloc(nthreads * sizeof (thread_t), KM_SLEEP);
332
333 if (flags & TASKQ_PREPOPULATE) {
334 mutex_enter(&tq->tq_lock);
335 while (minalloc-- > 0)
336 task_free(tq, task_alloc(tq, KM_SLEEP));
337 mutex_exit(&tq->tq_lock);
338 }
339
340 for (t = 0; t < nthreads; t++)
341 (void) thr_create(0, 0, taskq_thread,
342 tq, THR_BOUND, &tq->tq_threadlist[t]);
343
344 return (tq);
345 }
346
347 void
taskq_destroy(taskq_t * tq)348 taskq_destroy(taskq_t *tq)
349 {
350 int t;
351 int nthreads = tq->tq_nthreads;
352
353 taskq_wait(tq);
354
355 mutex_enter(&tq->tq_lock);
356
357 tq->tq_flags &= ~TASKQ_ACTIVE;
358 cv_broadcast(&tq->tq_dispatch_cv);
359
360 while (tq->tq_nthreads != 0)
361 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
362
363 tq->tq_minalloc = 0;
364 while (tq->tq_nalloc != 0) {
365 ASSERT(tq->tq_freelist != NULL);
366 task_free(tq, task_alloc(tq, KM_SLEEP));
367 }
368
369 mutex_exit(&tq->tq_lock);
370
371 for (t = 0; t < nthreads; t++)
372 (void) thr_join(tq->tq_threadlist[t], NULL, NULL);
373
374 kmem_free(tq->tq_threadlist, nthreads * sizeof (thread_t));
375
376 rw_destroy(&tq->tq_threadlock);
377 mutex_destroy(&tq->tq_lock);
378 cv_destroy(&tq->tq_dispatch_cv);
379 cv_destroy(&tq->tq_wait_cv);
380 cv_destroy(&tq->tq_maxalloc_cv);
381
382 kmem_free(tq, sizeof (taskq_t));
383 }
384
385 int
taskq_member(taskq_t * tq,struct _kthread * t)386 taskq_member(taskq_t *tq, struct _kthread *t)
387 {
388 int i;
389
390 if (taskq_now)
391 return (1);
392
393 for (i = 0; i < tq->tq_nthreads; i++)
394 if (tq->tq_threadlist[i] == (thread_t)(uintptr_t)t)
395 return (1);
396
397 return (0);
398 }
399
400 void
system_taskq_init(void)401 system_taskq_init(void)
402 {
403 system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512,
404 TASKQ_DYNAMIC | TASKQ_PREPOPULATE);
405 }
406
407 void
system_taskq_fini(void)408 system_taskq_fini(void)
409 {
410 taskq_destroy(system_taskq);
411 system_taskq = NULL; /* defensive */
412 }
413