e160730f02ef7581b10a8644811fe0ef17e6fb6e
[dragonfly.git] / sys / kern / subr_taskqueue.c
1 /*-
2  * Copyright (c) 2000 Doug Rabson
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  *       $FreeBSD: src/sys/kern/subr_taskqueue.c,v 1.1.2.3 2003/09/10 00:40:39 ken Exp $
27  *      $DragonFly: src/sys/kern/subr_taskqueue.c,v 1.13 2008/06/07 11:44:04 mneumann Exp $
28  */
29
30 #include <sys/param.h>
31 #include <sys/queue.h>
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/taskqueue.h>
35 #include <sys/interrupt.h>
36 #include <sys/lock.h>
37 #include <sys/malloc.h>
38 #include <sys/kthread.h>
39 #include <sys/thread2.h>
40 #include <sys/spinlock.h>
41 #include <sys/spinlock2.h>
42 #include <sys/serialize.h>
43 #include <sys/proc.h>
44 #include <machine/varargs.h>
45
46 MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
47
48 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
49 static struct lock      taskqueue_queues_lock;
50
51 struct taskqueue {
52         STAILQ_ENTRY(taskqueue) tq_link;
53         STAILQ_HEAD(, task)     tq_queue;
54         const char              *tq_name;
55         taskqueue_enqueue_fn    tq_enqueue;
56         void                    *tq_context;
57
58         struct task             *tq_running;
59         struct spinlock         tq_lock;
60         struct thread           **tq_threads;
61         int                     tq_tcount;
62         int                     tq_flags;
63 };
64
65 #define TQ_FLAGS_ACTIVE         (1 << 0)
66 #define TQ_FLAGS_BLOCKED        (1 << 1)
67 #define TQ_FLAGS_PENDING        (1 << 2)
68
69 static __inline void
70 TQ_LOCK_INIT(struct taskqueue *tq)
71 {
72         spin_init(&tq->tq_lock);
73 }
74
75 static __inline void
76 TQ_LOCK_UNINIT(struct taskqueue *tq)
77 {
78         spin_uninit(&tq->tq_lock);
79 }
80
81 static __inline void
82 TQ_LOCK(struct taskqueue *tq)
83 {
84         spin_lock_wr(&tq->tq_lock);
85 }
86
87 static __inline void
88 TQ_UNLOCK(struct taskqueue *tq)
89 {
90         spin_unlock_wr(&tq->tq_lock);
91 }
92
93 static __inline void
94 TQ_SLEEP(struct taskqueue *tq, void *ident, const char *wmesg)
95 {
96         ssleep(ident, &tq->tq_lock, 0, wmesg, 0);
97 }
98
99 struct taskqueue *
100 taskqueue_create(const char *name, int mflags,
101                  taskqueue_enqueue_fn enqueue, void *context)
102 {
103         struct taskqueue *queue;
104
105         queue = kmalloc(sizeof(*queue), M_TASKQUEUE, mflags | M_ZERO);
106         if (!queue)
107                 return NULL;
108         STAILQ_INIT(&queue->tq_queue);
109         queue->tq_name = name;
110         queue->tq_enqueue = enqueue;
111         queue->tq_context = context;
112         queue->tq_flags |= TQ_FLAGS_ACTIVE;
113         TQ_LOCK_INIT(queue);
114
115         lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
116         STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
117         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
118
119         return queue;
120 }
121
122 static void
123 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
124 {
125         while(tq->tq_tcount > 0) {
126                 wakeup(tq);
127                 TQ_SLEEP(tq, pp, "taskqueue_terminate");
128         }
129 }
130
131 void
132 taskqueue_free(struct taskqueue *queue)
133 {
134         TQ_LOCK(queue);
135         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
136         TQ_UNLOCK(queue);
137
138         taskqueue_run(queue);
139
140         TQ_LOCK(queue);
141         taskqueue_terminate(queue->tq_threads, queue);
142         TQ_UNLOCK(queue);
143
144         lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
145         STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
146         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
147
148         TQ_LOCK_UNINIT(queue);
149
150         kfree(queue, M_TASKQUEUE);
151 }
152
153 struct taskqueue *
154 taskqueue_find(const char *name)
155 {
156         struct taskqueue *queue;
157
158         lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
159         STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) {
160                 if (!strcmp(queue->tq_name, name)) {
161                         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
162                         return queue;
163                 }
164         }
165         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
166         return NULL;
167 }
168
169 /*
170  * NOTE!  If using the per-cpu taskqueues ``taskqueue_thread[mycpuid]'',
171  * be sure NOT TO SHARE the ``task'' between CPUs.  TASKS ARE NOT LOCKED.
172  * So either use a throwaway task which will only be enqueued once, or
173  * use one task per CPU!
174  */
175 int
176 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
177 {
178         struct task *ins;
179         struct task *prev;
180
181         TQ_LOCK(queue);
182
183         /*
184          * Don't allow new tasks on a queue which is being freed.
185          */
186         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0) {
187                 TQ_UNLOCK(queue);
188                 return EPIPE;
189         }
190
191         /*
192          * Count multiple enqueues.
193          */
194         if (task->ta_pending) {
195                 task->ta_pending++;
196                 TQ_UNLOCK(queue);
197                 return 0;
198         }
199
200         /*
201          * Optimise the case when all tasks have the same priority.
202          */
203         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
204         if (!prev || prev->ta_priority >= task->ta_priority) {
205                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
206         } else {
207                 prev = NULL;
208                 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
209                      prev = ins, ins = STAILQ_NEXT(ins, ta_link))
210                         if (ins->ta_priority < task->ta_priority)
211                                 break;
212
213                 if (prev)
214                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
215                 else
216                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
217         }
218
219         task->ta_pending = 1;
220         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) {
221                 if (queue->tq_enqueue)
222                         queue->tq_enqueue(queue->tq_context);
223         } else {
224                 queue->tq_flags |= TQ_FLAGS_PENDING;
225         }
226
227         TQ_UNLOCK(queue);
228
229         return 0;
230 }
231
232 void
233 taskqueue_block(struct taskqueue *queue)
234 {
235         TQ_LOCK(queue);
236         queue->tq_flags |= TQ_FLAGS_BLOCKED;
237         TQ_UNLOCK(queue);
238 }
239
240 void
241 taskqueue_unblock(struct taskqueue *queue)
242 {
243         TQ_LOCK(queue);
244         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
245         if (queue->tq_flags & TQ_FLAGS_PENDING) {
246                 queue->tq_flags &= ~TQ_FLAGS_PENDING;
247                 if (queue->tq_enqueue)
248                         queue->tq_enqueue(queue->tq_context);
249         }
250         TQ_UNLOCK(queue);
251 }
252
253 void
254 taskqueue_run(struct taskqueue *queue)
255 {
256         struct task *task;
257         int pending;
258
259         TQ_LOCK(queue);
260         while (STAILQ_FIRST(&queue->tq_queue)) {
261                 /*
262                  * Carefully remove the first task from the queue and
263                  * zero its pending count.
264                  */
265                 task = STAILQ_FIRST(&queue->tq_queue);
266                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
267                 pending = task->ta_pending;
268                 task->ta_pending = 0;
269                 queue->tq_running = task;
270                 TQ_UNLOCK(queue);
271
272                 task->ta_func(task->ta_context, pending);
273
274                 TQ_LOCK(queue);
275                 queue->tq_running = NULL;
276                 wakeup(task);
277         }
278         TQ_UNLOCK(queue);
279 }
280
281 void
282 taskqueue_drain(struct taskqueue *queue, struct task *task)
283 {
284         TQ_LOCK(queue);
285         while (task->ta_pending != 0 || task == queue->tq_running)
286                 TQ_SLEEP(queue, task, "-");
287         TQ_UNLOCK(queue);
288 }
289
290 static void
291 taskqueue_swi_enqueue(void *context)
292 {
293         setsofttq();
294 }
295
296 static void
297 taskqueue_swi_run(void *arg, void *frame)
298 {
299         taskqueue_run(taskqueue_swi);
300 }
301
302 static void
303 taskqueue_swi_mp_run(void *arg, void *frame)
304 {
305         taskqueue_run(taskqueue_swi_mp);
306 }
307
308 int
309 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, int ncpu,
310                         const char *fmt, ...)
311 {
312         __va_list ap;
313         struct thread *td;
314         struct taskqueue *tq;
315         int i, error, cpu;
316         char ktname[MAXCOMLEN];
317
318         if (count <= 0)
319                 return EINVAL;
320
321         tq = *tqp;
322         cpu = ncpu;
323
324         __va_start(ap, fmt);
325         kvsnprintf(ktname, MAXCOMLEN, fmt, ap);
326         __va_end(ap);
327
328         tq->tq_threads = kmalloc(sizeof(struct thread *) * count, M_TASKQUEUE,
329             M_WAITOK | M_ZERO);
330
331         for (i = 0; i < count; i++) {
332                 /*
333                  * If no specific cpu was specified and more than one thread
334                  * is to be created, we distribute the threads amongst all
335                  * cpus.
336                  */
337                 if ((ncpu <= -1) && (count > 1))
338                         cpu = i%ncpus;
339
340                 error = lwkt_create(taskqueue_thread_loop, tqp,
341                     &tq->tq_threads[i], NULL, TDF_STOPREQ | TDF_MPSAFE, cpu,
342                     "%s_%d", ktname, i);
343                 if (error) {
344                         kprintf("%s: kthread_add(%s): error %d", __func__,
345                             ktname, error);
346                         tq->tq_threads[i] = NULL;
347                 } else {
348                         td = tq->tq_threads[i];
349                         lwkt_setpri(td, pri);
350                         lwkt_schedule(td);
351                         tq->tq_tcount++;
352                 }
353         }
354
355         return 0;
356 }
357
358 void
359 taskqueue_thread_loop(void *arg)
360 {
361         struct taskqueue **tqp, *tq;
362
363         tqp = arg;
364         tq = *tqp;
365         TQ_LOCK(tq);
366         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
367                 taskqueue_run(tq);
368                 TQ_SLEEP(tq, tq, "tqthr");
369         }
370
371         /* rendezvous with thread that asked us to terminate */
372         tq->tq_tcount--;
373         wakeup_one(tq->tq_threads);
374         TQ_UNLOCK(tq);
375         lwkt_exit();
376 }
377
378 void
379 taskqueue_thread_enqueue(void *context)
380 {
381         struct taskqueue **tqp, *tq;
382
383         tqp = context;
384         tq = *tqp;
385
386         wakeup_one(tq);
387 }
388
389 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
390          register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL));
391 /*
392  * XXX: possibly use a different SWI_TQ_MP or so.
393  * related: sys/interrupt.h
394  * related: platform/XXX/isa/ipl_funcs.c
395  */
396 TASKQUEUE_DEFINE(swi_mp, taskqueue_swi_enqueue, 0,
397          register_swi(SWI_TQ, taskqueue_swi_mp_run, NULL, "swi_mp_taskq", NULL));
398
399 struct taskqueue *taskqueue_thread[MAXCPU];
400 static struct thread *taskqueue_thread_td[MAXCPU];
401
402 static void
403 taskqueue_init(void)
404 {
405         int cpu;
406
407         lockinit(&taskqueue_queues_lock, "tqqueues", 0, 0);
408         STAILQ_INIT(&taskqueue_queues);
409
410         for (cpu = 0; cpu < ncpus; cpu++) {
411                 taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT,
412                     taskqueue_thread_enqueue, &taskqueue_thread[cpu]);
413                 taskqueue_start_threads(&taskqueue_thread[cpu], 1,
414                     TDPRI_KERN_DAEMON, cpu, "taskq_cpu");
415         }
416 }
417
418 SYSINIT(taskqueueinit, SI_SUB_PRE_DRIVERS, SI_ORDER_ANY, taskqueue_init, NULL);