Initial import from FreeBSD RELENG_4:
[dragonfly.git] / sys / kern / subr_taskqueue.c
CommitLineData
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MD
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 1.1.2.2 2001/03/31 03:33:44 hsu 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/malloc.h>
36#include <machine/ipl.h>
37
38MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
39
40static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
41
42struct taskqueue {
43 STAILQ_ENTRY(taskqueue) tq_link;
44 STAILQ_HEAD(, task) tq_queue;
45 const char *tq_name;
46 taskqueue_enqueue_fn tq_enqueue;
47 void *tq_context;
48 int tq_draining;
49};
50
51struct taskqueue *
52taskqueue_create(const char *name, int mflags,
53 taskqueue_enqueue_fn enqueue, void *context)
54{
55 struct taskqueue *queue;
56 static int once = 1;
57 int s;
58
59 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags);
60 if (!queue)
61 return 0;
62 STAILQ_INIT(&queue->tq_queue);
63 queue->tq_name = name;
64 queue->tq_enqueue = enqueue;
65 queue->tq_context = context;
66 queue->tq_draining = 0;
67
68 s = splhigh();
69 if (once) {
70 STAILQ_INIT(&taskqueue_queues);
71 once = 0;
72 }
73 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
74 splx(s);
75
76 return queue;
77}
78
79void
80taskqueue_free(struct taskqueue *queue)
81{
82 int s = splhigh();
83 queue->tq_draining = 1;
84 splx(s);
85
86 taskqueue_run(queue);
87
88 s = splhigh();
89 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
90 splx(s);
91
92 free(queue, M_TASKQUEUE);
93}
94
95struct taskqueue *
96taskqueue_find(const char *name)
97{
98 struct taskqueue *queue;
99 int s;
100
101 s = splhigh();
102 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link)
103 if (!strcmp(queue->tq_name, name)) {
104 splx(s);
105 return queue;
106 }
107 splx(s);
108 return 0;
109}
110
111int
112taskqueue_enqueue(struct taskqueue *queue, struct task *task)
113{
114 struct task *ins;
115 struct task *prev;
116
117 int s = splhigh();
118
119 /*
120 * Don't allow new tasks on a queue which is being freed.
121 */
122 if (queue->tq_draining) {
123 splx(s);
124 return EPIPE;
125 }
126
127 /*
128 * Count multiple enqueues.
129 */
130 if (task->ta_pending) {
131 task->ta_pending++;
132 splx(s);
133 return 0;
134 }
135
136 /*
137 * Optimise the case when all tasks have the same priority.
138 */
139 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
140 if (!prev || prev->ta_priority >= task->ta_priority) {
141 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
142 } else {
143 prev = 0;
144 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
145 prev = ins, ins = STAILQ_NEXT(ins, ta_link))
146 if (ins->ta_priority < task->ta_priority)
147 break;
148
149 if (prev)
150 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
151 else
152 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
153 }
154
155 task->ta_pending = 1;
156 if (queue->tq_enqueue)
157 queue->tq_enqueue(queue->tq_context);
158
159 splx(s);
160
161 return 0;
162}
163
164void
165taskqueue_run(struct taskqueue *queue)
166{
167 int s;
168 struct task *task;
169 int pending;
170
171 s = splhigh();
172 while (STAILQ_FIRST(&queue->tq_queue)) {
173 /*
174 * Carefully remove the first task from the queue and
175 * zero its pending count.
176 */
177 task = STAILQ_FIRST(&queue->tq_queue);
178 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
179 pending = task->ta_pending;
180 task->ta_pending = 0;
181 splx(s);
182
183 task->ta_func(task->ta_context, pending);
184
185 s = splhigh();
186 }
187 splx(s);
188}
189
190static void
191taskqueue_swi_enqueue(void *context)
192{
193 setsofttq();
194}
195
196static void
197taskqueue_swi_run(void)
198{
199 taskqueue_run(taskqueue_swi);
200}
201
202TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
203 register_swi(SWI_TQ, taskqueue_swi_run));