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> */
47extern long sysconf(int);
48
49/* avoiding <thread.h> */
50typedef unsigned int thread_t;
51typedef unsigned int thread_key_t;
52
53extern int thr_create(void *, size_t, void *(*)(void *), void *, long,
54			thread_t *);
55extern 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
70int taskq_now;
71taskq_t *system_taskq;
72
73#define	TASKQ_ACTIVE	0x00010000
74
75struct 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
93static taskq_ent_t *
94task_alloc(taskq_t *tq, int tqflags)
95{
96	taskq_ent_t *t;
97	int rv;
98
99again:	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
134static void
135task_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
151taskqid_t
152taskq_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
184void
185taskq_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
216boolean_t
217taskq_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
228void
229taskq_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
237void
238taskq_wait_id(taskq_t *tq, taskqid_t id __unused)
239{
240	taskq_wait(tq);
241}
242
243static void *
244taskq_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*/
281taskq_t *
282taskq_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*/
290taskq_t *
291taskq_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*/
299taskq_t *
300taskq_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
347void
348taskq_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
385int
386taskq_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
400void
401system_taskq_init(void)
402{
403	system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512,
404	    TASKQ_DYNAMIC | TASKQ_PREPOPULATE);
405}
406
407void
408system_taskq_fini(void)
409{
410	taskq_destroy(system_taskq);
411	system_taskq = NULL; /* defensive */
412}
413