tests: virtio-9p: code refactoring
[qemu.git] / iothread.c
1 /*
2 * Event loop thread
3 *
4 * Copyright Red Hat Inc., 2013
5 *
6 * Authors:
7 * Stefan Hajnoczi <stefanha@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
11 *
12 */
13
14 #include "qemu/osdep.h"
15 #include "qom/object.h"
16 #include "qom/object_interfaces.h"
17 #include "qemu/module.h"
18 #include "block/aio.h"
19 #include "block/block.h"
20 #include "sysemu/iothread.h"
21 #include "qmp-commands.h"
22 #include "qemu/error-report.h"
23 #include "qemu/rcu.h"
24 #include "qemu/main-loop.h"
25
26 typedef ObjectClass IOThreadClass;
27
28 #define IOTHREAD_GET_CLASS(obj) \
29 OBJECT_GET_CLASS(IOThreadClass, obj, TYPE_IOTHREAD)
30 #define IOTHREAD_CLASS(klass) \
31 OBJECT_CLASS_CHECK(IOThreadClass, klass, TYPE_IOTHREAD)
32
33 static __thread IOThread *my_iothread;
34
35 AioContext *qemu_get_current_aio_context(void)
36 {
37 return my_iothread ? my_iothread->ctx : qemu_get_aio_context();
38 }
39
40 static void *iothread_run(void *opaque)
41 {
42 IOThread *iothread = opaque;
43
44 rcu_register_thread();
45
46 my_iothread = iothread;
47 qemu_mutex_lock(&iothread->init_done_lock);
48 iothread->thread_id = qemu_get_thread_id();
49 qemu_cond_signal(&iothread->init_done_cond);
50 qemu_mutex_unlock(&iothread->init_done_lock);
51
52 while (!atomic_read(&iothread->stopping)) {
53 aio_poll(iothread->ctx, true);
54 }
55
56 rcu_unregister_thread();
57 return NULL;
58 }
59
60 static int iothread_stop(Object *object, void *opaque)
61 {
62 IOThread *iothread;
63
64 iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
65 if (!iothread || !iothread->ctx) {
66 return 0;
67 }
68 iothread->stopping = true;
69 aio_notify(iothread->ctx);
70 qemu_thread_join(&iothread->thread);
71 return 0;
72 }
73
74 static void iothread_instance_finalize(Object *obj)
75 {
76 IOThread *iothread = IOTHREAD(obj);
77
78 iothread_stop(obj, NULL);
79 qemu_cond_destroy(&iothread->init_done_cond);
80 qemu_mutex_destroy(&iothread->init_done_lock);
81 if (!iothread->ctx) {
82 return;
83 }
84 aio_context_unref(iothread->ctx);
85 }
86
87 static void iothread_complete(UserCreatable *obj, Error **errp)
88 {
89 Error *local_error = NULL;
90 IOThread *iothread = IOTHREAD(obj);
91 char *name, *thread_name;
92
93 iothread->stopping = false;
94 iothread->thread_id = -1;
95 iothread->ctx = aio_context_new(&local_error);
96 if (!iothread->ctx) {
97 error_propagate(errp, local_error);
98 return;
99 }
100
101 qemu_mutex_init(&iothread->init_done_lock);
102 qemu_cond_init(&iothread->init_done_cond);
103
104 /* This assumes we are called from a thread with useful CPU affinity for us
105 * to inherit.
106 */
107 name = object_get_canonical_path_component(OBJECT(obj));
108 thread_name = g_strdup_printf("IO %s", name);
109 qemu_thread_create(&iothread->thread, thread_name, iothread_run,
110 iothread, QEMU_THREAD_JOINABLE);
111 g_free(thread_name);
112 g_free(name);
113
114 /* Wait for initialization to complete */
115 qemu_mutex_lock(&iothread->init_done_lock);
116 while (iothread->thread_id == -1) {
117 qemu_cond_wait(&iothread->init_done_cond,
118 &iothread->init_done_lock);
119 }
120 qemu_mutex_unlock(&iothread->init_done_lock);
121 }
122
123 static void iothread_class_init(ObjectClass *klass, void *class_data)
124 {
125 UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
126 ucc->complete = iothread_complete;
127 }
128
129 static const TypeInfo iothread_info = {
130 .name = TYPE_IOTHREAD,
131 .parent = TYPE_OBJECT,
132 .class_init = iothread_class_init,
133 .instance_size = sizeof(IOThread),
134 .instance_finalize = iothread_instance_finalize,
135 .interfaces = (InterfaceInfo[]) {
136 {TYPE_USER_CREATABLE},
137 {}
138 },
139 };
140
141 static void iothread_register_types(void)
142 {
143 type_register_static(&iothread_info);
144 }
145
146 type_init(iothread_register_types)
147
148 char *iothread_get_id(IOThread *iothread)
149 {
150 return object_get_canonical_path_component(OBJECT(iothread));
151 }
152
153 AioContext *iothread_get_aio_context(IOThread *iothread)
154 {
155 return iothread->ctx;
156 }
157
158 static int query_one_iothread(Object *object, void *opaque)
159 {
160 IOThreadInfoList ***prev = opaque;
161 IOThreadInfoList *elem;
162 IOThreadInfo *info;
163 IOThread *iothread;
164
165 iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
166 if (!iothread) {
167 return 0;
168 }
169
170 info = g_new0(IOThreadInfo, 1);
171 info->id = iothread_get_id(iothread);
172 info->thread_id = iothread->thread_id;
173
174 elem = g_new0(IOThreadInfoList, 1);
175 elem->value = info;
176 elem->next = NULL;
177
178 **prev = elem;
179 *prev = &elem->next;
180 return 0;
181 }
182
183 IOThreadInfoList *qmp_query_iothreads(Error **errp)
184 {
185 IOThreadInfoList *head = NULL;
186 IOThreadInfoList **prev = &head;
187 Object *container = object_get_objects_root();
188
189 object_child_foreach(container, query_one_iothread, &prev);
190 return head;
191 }
192
193 void iothread_stop_all(void)
194 {
195 Object *container = object_get_objects_root();
196 BlockDriverState *bs;
197 BdrvNextIterator it;
198
199 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
200 AioContext *ctx = bdrv_get_aio_context(bs);
201 if (ctx == qemu_get_aio_context()) {
202 continue;
203 }
204 aio_context_acquire(ctx);
205 bdrv_set_aio_context(bs, qemu_get_aio_context());
206 aio_context_release(ctx);
207 }
208
209 object_child_foreach(container, iothread_stop, NULL);
210 }