33a30f2db876842ae68a13fd56eb5db67084be55
[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  */
28
29 #include <sys/param.h>
30 #include <sys/queue.h>
31 #include <sys/systm.h>
32 #include <sys/kernel.h>
33 #include <sys/taskqueue.h>
34 #include <sys/interrupt.h>
35 #include <sys/lock.h>
36 #include <sys/malloc.h>
37 #include <sys/kthread.h>
38 #include <sys/thread2.h>
39 #include <sys/spinlock.h>
40 #include <sys/spinlock2.h>
41 #include <sys/serialize.h>
42 #include <sys/proc.h>
43 #include <machine/varargs.h>
44
45 MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
46
47 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
48 static struct lock      taskqueue_queues_lock;
49
50 struct taskqueue {
51         STAILQ_ENTRY(taskqueue) tq_link;
52         STAILQ_HEAD(, task)     tq_queue;
53         const char              *tq_name;
54         taskqueue_enqueue_fn    tq_enqueue;
55         void                    *tq_context;
56
57         struct task             *tq_running;
58         struct spinlock         tq_lock;
59         struct thread           **tq_threads;
60         int                     tq_tcount;
61         int                     tq_flags;
62 };
63
64 #define TQ_FLAGS_ACTIVE         (1 << 0)
65 #define TQ_FLAGS_BLOCKED        (1 << 1)
66 #define TQ_FLAGS_PENDING        (1 << 2)
67
68 static void taskqueue_run(struct taskqueue *queue, int lock_held);
69
70 static __inline void
71 TQ_LOCK_INIT(struct taskqueue *tq)
72 {
73         spin_init(&tq->tq_lock);
74 }
75
76 static __inline void
77 TQ_LOCK_UNINIT(struct taskqueue *tq)
78 {
79         spin_uninit(&tq->tq_lock);
80 }
81
82 static __inline void
83 TQ_LOCK(struct taskqueue *tq)
84 {
85         spin_lock(&tq->tq_lock);
86 }
87
88 static __inline void
89 TQ_UNLOCK(struct taskqueue *tq)
90 {
91         spin_unlock(&tq->tq_lock);
92 }
93
94 static __inline void
95 TQ_SLEEP(struct taskqueue *tq, void *ident, const char *wmesg)
96 {
97         ssleep(ident, &tq->tq_lock, 0, wmesg, 0);
98 }
99
100 struct taskqueue *
101 taskqueue_create(const char *name, int mflags,
102                  taskqueue_enqueue_fn enqueue, void *context)
103 {
104         struct taskqueue *queue;
105
106         queue = kmalloc(sizeof(*queue), M_TASKQUEUE, mflags | M_ZERO);
107         if (!queue)
108                 return NULL;
109         STAILQ_INIT(&queue->tq_queue);
110         queue->tq_name = name;
111         queue->tq_enqueue = enqueue;
112         queue->tq_context = context;
113         queue->tq_flags |= TQ_FLAGS_ACTIVE;
114         TQ_LOCK_INIT(queue);
115
116         lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
117         STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
118         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
119
120         return queue;
121 }
122
123 static void
124 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
125 {
126         while(tq->tq_tcount > 0) {
127                 wakeup(tq);
128                 TQ_SLEEP(tq, pp, "taskqueue_terminate");
129         }
130 }
131
132 void
133 taskqueue_free(struct taskqueue *queue)
134 {
135         TQ_LOCK(queue);
136         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
137         taskqueue_run(queue, 1);
138         taskqueue_terminate(queue->tq_threads, queue);
139         TQ_UNLOCK(queue);
140
141         lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
142         STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
143         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
144
145         TQ_LOCK_UNINIT(queue);
146
147         kfree(queue, M_TASKQUEUE);
148 }
149
150 struct taskqueue *
151 taskqueue_find(const char *name)
152 {
153         struct taskqueue *queue;
154
155         lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
156         STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) {
157                 if (!strcmp(queue->tq_name, name)) {
158                         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
159                         return queue;
160                 }
161         }
162         lockmgr(&taskqueue_queues_lock, LK_RELEASE);
163         return NULL;
164 }
165
166 /*
167  * NOTE!  If using the per-cpu taskqueues ``taskqueue_thread[mycpuid]'',
168  * be sure NOT TO SHARE the ``task'' between CPUs.  TASKS ARE NOT LOCKED.
169  * So either use a throwaway task which will only be enqueued once, or
170  * use one task per CPU!
171  */
172 int
173 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
174 {
175         struct task *ins;
176         struct task *prev;
177
178         TQ_LOCK(queue);
179
180         /*
181          * Don't allow new tasks on a queue which is being freed.
182          */
183         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0) {
184                 TQ_UNLOCK(queue);
185                 return EPIPE;
186         }
187
188         /*
189          * Count multiple enqueues.
190          */
191         if (task->ta_pending) {
192                 task->ta_pending++;
193                 TQ_UNLOCK(queue);
194                 return 0;
195         }
196
197         /*
198          * Optimise the case when all tasks have the same priority.
199          */
200         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
201         if (!prev || prev->ta_priority >= task->ta_priority) {
202                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
203         } else {
204                 prev = NULL;
205                 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
206                      prev = ins, ins = STAILQ_NEXT(ins, ta_link))
207                         if (ins->ta_priority < task->ta_priority)
208                                 break;
209
210                 if (prev)
211                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
212                 else
213                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
214         }
215
216         task->ta_pending = 1;
217         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) {
218                 if (queue->tq_enqueue)
219                         queue->tq_enqueue(queue->tq_context);
220         } else {
221                 queue->tq_flags |= TQ_FLAGS_PENDING;
222         }
223
224         TQ_UNLOCK(queue);
225
226         return 0;
227 }
228
229 void
230 taskqueue_block(struct taskqueue *queue)
231 {
232         TQ_LOCK(queue);
233         queue->tq_flags |= TQ_FLAGS_BLOCKED;
234         TQ_UNLOCK(queue);
235 }
236
237 void
238 taskqueue_unblock(struct taskqueue *queue)
239 {
240         TQ_LOCK(queue);
241         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
242         if (queue->tq_flags & TQ_FLAGS_PENDING) {
243                 queue->tq_flags &= ~TQ_FLAGS_PENDING;
244                 if (queue->tq_enqueue)
245                         queue->tq_enqueue(queue->tq_context);
246         }
247         TQ_UNLOCK(queue);
248 }
249
250 void
251 taskqueue_run(struct taskqueue *queue, int lock_held)
252 {
253         struct task *task;
254         int pending;
255
256         if (lock_held == 0)
257                 TQ_LOCK(queue);
258         while (STAILQ_FIRST(&queue->tq_queue)) {
259                 /*
260                  * Carefully remove the first task from the queue and
261                  * zero its pending count.
262                  */
263                 task = STAILQ_FIRST(&queue->tq_queue);
264                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
265                 pending = task->ta_pending;
266                 task->ta_pending = 0;
267                 queue->tq_running = task;
268                 TQ_UNLOCK(queue);
269
270                 task->ta_func(task->ta_context, pending);
271
272                 TQ_LOCK(queue);
273                 queue->tq_running = NULL;
274                 wakeup(task);
275         }
276         if (lock_held == 0)
277                 TQ_UNLOCK(queue);
278 }
279
280 void
281 taskqueue_drain(struct taskqueue *queue, struct task *task)
282 {
283         TQ_LOCK(queue);
284         while (task->ta_pending != 0 || task == queue->tq_running)
285                 TQ_SLEEP(queue, task, "-");
286         TQ_UNLOCK(queue);
287 }
288
289 static void
290 taskqueue_swi_enqueue(void *context)
291 {
292         setsofttq();
293 }
294
295 static void
296 taskqueue_swi_run(void *arg, void *frame)
297 {
298         taskqueue_run(taskqueue_swi, 0);
299 }
300
301 static void
302 taskqueue_swi_mp_run(void *arg, void *frame)
303 {
304         taskqueue_run(taskqueue_swi_mp, 0);
305 }
306
307 int
308 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, int ncpu,
309                         const char *fmt, ...)
310 {
311         __va_list ap;
312         struct thread *td;
313         struct taskqueue *tq;
314         int i, error, cpu;
315         char ktname[MAXCOMLEN];
316
317         if (count <= 0)
318                 return EINVAL;
319
320         tq = *tqp;
321         cpu = ncpu;
322
323         __va_start(ap, fmt);
324         kvsnprintf(ktname, MAXCOMLEN, fmt, ap);
325         __va_end(ap);
326
327         tq->tq_threads = kmalloc(sizeof(struct thread *) * count, M_TASKQUEUE,
328             M_WAITOK | M_ZERO);
329
330         for (i = 0; i < count; i++) {
331                 /*
332                  * If no specific cpu was specified and more than one thread
333                  * is to be created, we distribute the threads amongst all
334                  * cpus.
335                  */
336                 if ((ncpu <= -1) && (count > 1))
337                         cpu = i%ncpus;
338
339                 if (count == 1) {
340                         error = lwkt_create(taskqueue_thread_loop, tqp,
341                                             &tq->tq_threads[i], NULL,
342                                             TDF_STOPREQ, cpu,
343                                             "%s", ktname);
344                 } else {
345                         error = lwkt_create(taskqueue_thread_loop, tqp,
346                                             &tq->tq_threads[i], NULL,
347                                             TDF_STOPREQ, cpu,
348                                             "%s_%d", ktname, i);
349                 }
350                 if (error) {
351                         kprintf("%s: lwkt_create(%s): error %d", __func__,
352                             ktname, error);
353                         tq->tq_threads[i] = NULL;
354                 } else {
355                         td = tq->tq_threads[i];
356                         lwkt_setpri_initial(td, pri);
357                         lwkt_schedule(td);
358                         tq->tq_tcount++;
359                 }
360         }
361
362         return 0;
363 }
364
365 void
366 taskqueue_thread_loop(void *arg)
367 {
368         struct taskqueue **tqp, *tq;
369
370         tqp = arg;
371         tq = *tqp;
372         TQ_LOCK(tq);
373         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
374                 taskqueue_run(tq, 1);
375                 TQ_SLEEP(tq, tq, "tqthr");
376         }
377
378         /* rendezvous with thread that asked us to terminate */
379         tq->tq_tcount--;
380         wakeup_one(tq->tq_threads);
381         TQ_UNLOCK(tq);
382         lwkt_exit();
383 }
384
385 void
386 taskqueue_thread_enqueue(void *context)
387 {
388         struct taskqueue **tqp, *tq;
389
390         tqp = context;
391         tq = *tqp;
392
393         wakeup_one(tq);
394 }
395
396 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
397          register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL, -1));
398 /*
399  * XXX: possibly use a different SWI_TQ_MP or so.
400  * related: sys/interrupt.h
401  * related: platform/XXX/isa/ipl_funcs.c
402  */
403 TASKQUEUE_DEFINE(swi_mp, taskqueue_swi_enqueue, 0,
404     register_swi(SWI_TQ, taskqueue_swi_mp_run, NULL, "swi_mp_taskq", NULL, -1));
405
406 struct taskqueue *taskqueue_thread[MAXCPU];
407
408 static void
409 taskqueue_init(void)
410 {
411         int cpu;
412
413         lockinit(&taskqueue_queues_lock, "tqqueues", 0, 0);
414         STAILQ_INIT(&taskqueue_queues);
415
416         for (cpu = 0; cpu < ncpus; cpu++) {
417                 taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT,
418                     taskqueue_thread_enqueue, &taskqueue_thread[cpu]);
419                 taskqueue_start_threads(&taskqueue_thread[cpu], 1,
420                     TDPRI_KERN_DAEMON, cpu, "taskq_cpu %d", cpu);
421         }
422 }
423
424 SYSINIT(taskqueueinit, SI_SUB_PRE_DRIVERS, SI_ORDER_ANY, taskqueue_init, NULL);