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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 | aio_context_set_poll_params(iothread->ctx, | |
102 | iothread->poll_max_ns, | |
103 | iothread->poll_grow, | |
104 | iothread->poll_shrink, | |
105 | &local_error); | |
106 | if (local_error) { | |
107 | error_propagate(errp, local_error); | |
108 | aio_context_unref(iothread->ctx); | |
109 | iothread->ctx = NULL; | |
110 | return; | |
111 | } | |
112 | ||
113 | qemu_mutex_init(&iothread->init_done_lock); | |
114 | qemu_cond_init(&iothread->init_done_cond); | |
115 | ||
116 | /* This assumes we are called from a thread with useful CPU affinity for us | |
117 | * to inherit. | |
118 | */ | |
119 | name = object_get_canonical_path_component(OBJECT(obj)); | |
120 | thread_name = g_strdup_printf("IO %s", name); | |
121 | qemu_thread_create(&iothread->thread, thread_name, iothread_run, | |
122 | iothread, QEMU_THREAD_JOINABLE); | |
123 | g_free(thread_name); | |
124 | g_free(name); | |
125 | ||
126 | /* Wait for initialization to complete */ | |
127 | qemu_mutex_lock(&iothread->init_done_lock); | |
128 | while (iothread->thread_id == -1) { | |
129 | qemu_cond_wait(&iothread->init_done_cond, | |
130 | &iothread->init_done_lock); | |
131 | } | |
132 | qemu_mutex_unlock(&iothread->init_done_lock); | |
133 | } | |
134 | ||
135 | typedef struct { | |
136 | const char *name; | |
137 | ptrdiff_t offset; /* field's byte offset in IOThread struct */ | |
138 | } PollParamInfo; | |
139 | ||
140 | static PollParamInfo poll_max_ns_info = { | |
141 | "poll-max-ns", offsetof(IOThread, poll_max_ns), | |
142 | }; | |
143 | static PollParamInfo poll_grow_info = { | |
144 | "poll-grow", offsetof(IOThread, poll_grow), | |
145 | }; | |
146 | static PollParamInfo poll_shrink_info = { | |
147 | "poll-shrink", offsetof(IOThread, poll_shrink), | |
148 | }; | |
149 | ||
150 | static void iothread_get_poll_param(Object *obj, Visitor *v, | |
151 | const char *name, void *opaque, Error **errp) | |
152 | { | |
153 | IOThread *iothread = IOTHREAD(obj); | |
154 | PollParamInfo *info = opaque; | |
155 | int64_t *field = (void *)iothread + info->offset; | |
156 | ||
157 | visit_type_int64(v, name, field, errp); | |
158 | } | |
159 | ||
160 | static void iothread_set_poll_param(Object *obj, Visitor *v, | |
161 | const char *name, void *opaque, Error **errp) | |
162 | { | |
163 | IOThread *iothread = IOTHREAD(obj); | |
164 | PollParamInfo *info = opaque; | |
165 | int64_t *field = (void *)iothread + info->offset; | |
166 | Error *local_err = NULL; | |
167 | int64_t value; | |
168 | ||
169 | visit_type_int64(v, name, &value, &local_err); | |
170 | if (local_err) { | |
171 | goto out; | |
172 | } | |
173 | ||
174 | if (value < 0) { | |
175 | error_setg(&local_err, "%s value must be in range [0, %"PRId64"]", | |
176 | info->name, INT64_MAX); | |
177 | goto out; | |
178 | } | |
179 | ||
180 | *field = value; | |
181 | ||
182 | if (iothread->ctx) { | |
183 | aio_context_set_poll_params(iothread->ctx, | |
184 | iothread->poll_max_ns, | |
185 | iothread->poll_grow, | |
186 | iothread->poll_shrink, | |
187 | &local_err); | |
188 | } | |
189 | ||
190 | out: | |
191 | error_propagate(errp, local_err); | |
192 | } | |
193 | ||
194 | static void iothread_class_init(ObjectClass *klass, void *class_data) | |
195 | { | |
196 | UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass); | |
197 | ucc->complete = iothread_complete; | |
198 | ||
199 | object_class_property_add(klass, "poll-max-ns", "int", | |
200 | iothread_get_poll_param, | |
201 | iothread_set_poll_param, | |
202 | NULL, &poll_max_ns_info, &error_abort); | |
203 | object_class_property_add(klass, "poll-grow", "int", | |
204 | iothread_get_poll_param, | |
205 | iothread_set_poll_param, | |
206 | NULL, &poll_grow_info, &error_abort); | |
207 | object_class_property_add(klass, "poll-shrink", "int", | |
208 | iothread_get_poll_param, | |
209 | iothread_set_poll_param, | |
210 | NULL, &poll_shrink_info, &error_abort); | |
211 | } | |
212 | ||
213 | static const TypeInfo iothread_info = { | |
214 | .name = TYPE_IOTHREAD, | |
215 | .parent = TYPE_OBJECT, | |
216 | .class_init = iothread_class_init, | |
217 | .instance_size = sizeof(IOThread), | |
218 | .instance_finalize = iothread_instance_finalize, | |
219 | .interfaces = (InterfaceInfo[]) { | |
220 | {TYPE_USER_CREATABLE}, | |
221 | {} | |
222 | }, | |
223 | }; | |
224 | ||
225 | static void iothread_register_types(void) | |
226 | { | |
227 | type_register_static(&iothread_info); | |
228 | } | |
229 | ||
230 | type_init(iothread_register_types) | |
231 | ||
232 | char *iothread_get_id(IOThread *iothread) | |
233 | { | |
234 | return object_get_canonical_path_component(OBJECT(iothread)); | |
235 | } | |
236 | ||
237 | AioContext *iothread_get_aio_context(IOThread *iothread) | |
238 | { | |
239 | return iothread->ctx; | |
240 | } | |
241 | ||
242 | static int query_one_iothread(Object *object, void *opaque) | |
243 | { | |
244 | IOThreadInfoList ***prev = opaque; | |
245 | IOThreadInfoList *elem; | |
246 | IOThreadInfo *info; | |
247 | IOThread *iothread; | |
248 | ||
249 | iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD); | |
250 | if (!iothread) { | |
251 | return 0; | |
252 | } | |
253 | ||
254 | info = g_new0(IOThreadInfo, 1); | |
255 | info->id = iothread_get_id(iothread); | |
256 | info->thread_id = iothread->thread_id; | |
257 | ||
258 | elem = g_new0(IOThreadInfoList, 1); | |
259 | elem->value = info; | |
260 | elem->next = NULL; | |
261 | ||
262 | **prev = elem; | |
263 | *prev = &elem->next; | |
264 | return 0; | |
265 | } | |
266 | ||
267 | IOThreadInfoList *qmp_query_iothreads(Error **errp) | |
268 | { | |
269 | IOThreadInfoList *head = NULL; | |
270 | IOThreadInfoList **prev = &head; | |
271 | Object *container = object_get_objects_root(); | |
272 | ||
273 | object_child_foreach(container, query_one_iothread, &prev); | |
274 | return head; | |
275 | } | |
276 | ||
277 | void iothread_stop_all(void) | |
278 | { | |
279 | Object *container = object_get_objects_root(); | |
280 | BlockDriverState *bs; | |
281 | BdrvNextIterator it; | |
282 | ||
283 | for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { | |
284 | AioContext *ctx = bdrv_get_aio_context(bs); | |
285 | if (ctx == qemu_get_aio_context()) { | |
286 | continue; | |
287 | } | |
288 | aio_context_acquire(ctx); | |
289 | bdrv_set_aio_context(bs, qemu_get_aio_context()); | |
290 | aio_context_release(ctx); | |
291 | } | |
292 | ||
293 | object_child_foreach(container, iothread_stop, NULL); | |
294 | } |