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Commit | Line | Data |
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be8d8537 SH |
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 | ||
d38ea87a | 14 | #include "qemu/osdep.h" |
be8d8537 SH |
15 | #include "qom/object.h" |
16 | #include "qom/object_interfaces.h" | |
17 | #include "qemu/module.h" | |
be8d8537 | 18 | #include "block/aio.h" |
d16341fa | 19 | #include "block/block.h" |
be8d8537 | 20 | #include "sysemu/iothread.h" |
e688df6b | 21 | #include "qapi/error.h" |
112ed241 | 22 | #include "qapi/qapi-commands-misc.h" |
2f78e491 | 23 | #include "qemu/error-report.h" |
ab28bd23 | 24 | #include "qemu/rcu.h" |
e4370165 | 25 | #include "qemu/main-loop.h" |
be8d8537 | 26 | |
be8d8537 | 27 | typedef ObjectClass IOThreadClass; |
be8d8537 SH |
28 | |
29 | #define IOTHREAD_GET_CLASS(obj) \ | |
30 | OBJECT_GET_CLASS(IOThreadClass, obj, TYPE_IOTHREAD) | |
31 | #define IOTHREAD_CLASS(klass) \ | |
32 | OBJECT_CLASS_CHECK(IOThreadClass, klass, TYPE_IOTHREAD) | |
33 | ||
90c558be | 34 | #ifdef CONFIG_POSIX |
cdd7abfd SH |
35 | /* Benchmark results from 2016 on NVMe SSD drives show max polling times around |
36 | * 16-32 microseconds yield IOPS improvements for both iodepth=1 and iodepth=32 | |
37 | * workloads. | |
38 | */ | |
39 | #define IOTHREAD_POLL_MAX_NS_DEFAULT 32768ULL | |
90c558be PX |
40 | #else |
41 | #define IOTHREAD_POLL_MAX_NS_DEFAULT 0ULL | |
42 | #endif | |
cdd7abfd | 43 | |
e4370165 PB |
44 | static __thread IOThread *my_iothread; |
45 | ||
46 | AioContext *qemu_get_current_aio_context(void) | |
47 | { | |
48 | return my_iothread ? my_iothread->ctx : qemu_get_aio_context(); | |
49 | } | |
50 | ||
be8d8537 SH |
51 | static void *iothread_run(void *opaque) |
52 | { | |
53 | IOThread *iothread = opaque; | |
54 | ||
ab28bd23 | 55 | rcu_register_thread(); |
b60ec76a PX |
56 | /* |
57 | * g_main_context_push_thread_default() must be called before anything | |
58 | * in this new thread uses glib. | |
59 | */ | |
60 | g_main_context_push_thread_default(iothread->worker_context); | |
e4370165 | 61 | my_iothread = iothread; |
88eb7c29 | 62 | iothread->thread_id = qemu_get_thread_id(); |
21c4d15b | 63 | qemu_sem_post(&iothread->init_done_sem); |
88eb7c29 | 64 | |
2362a28e | 65 | while (iothread->running) { |
65c1b5b6 | 66 | aio_poll(iothread->ctx, true); |
329163cb | 67 | |
6c95363d PX |
68 | /* |
69 | * We must check the running state again in case it was | |
70 | * changed in previous aio_poll() | |
71 | */ | |
b506e0f1 | 72 | if (iothread->running && atomic_read(&iothread->run_gcontext)) { |
329163cb | 73 | g_main_loop_run(iothread->main_loop); |
329163cb | 74 | } |
be8d8537 | 75 | } |
ab28bd23 | 76 | |
b60ec76a | 77 | g_main_context_pop_thread_default(iothread->worker_context); |
ab28bd23 | 78 | rcu_unregister_thread(); |
be8d8537 SH |
79 | return NULL; |
80 | } | |
81 | ||
2362a28e SH |
82 | /* Runs in iothread_run() thread */ |
83 | static void iothread_stop_bh(void *opaque) | |
84 | { | |
85 | IOThread *iothread = opaque; | |
86 | ||
87 | iothread->running = false; /* stop iothread_run() */ | |
88 | ||
89 | if (iothread->main_loop) { | |
90 | g_main_loop_quit(iothread->main_loop); | |
91 | } | |
92 | } | |
93 | ||
82d90705 | 94 | void iothread_stop(IOThread *iothread) |
be8d8537 | 95 | { |
82d90705 PX |
96 | if (!iothread->ctx || iothread->stopping) { |
97 | return; | |
2f78e491 | 98 | } |
be8d8537 | 99 | iothread->stopping = true; |
2362a28e | 100 | aio_bh_schedule_oneshot(iothread->ctx, iothread_stop_bh, iothread); |
be8d8537 | 101 | qemu_thread_join(&iothread->thread); |
82d90705 PX |
102 | } |
103 | ||
cdd7abfd SH |
104 | static void iothread_instance_init(Object *obj) |
105 | { | |
106 | IOThread *iothread = IOTHREAD(obj); | |
107 | ||
108 | iothread->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT; | |
14a2d118 | 109 | iothread->thread_id = -1; |
21c4d15b | 110 | qemu_sem_init(&iothread->init_done_sem, 0); |
b506e0f1 PX |
111 | /* By default, we don't run gcontext */ |
112 | atomic_set(&iothread->run_gcontext, 0); | |
cdd7abfd SH |
113 | } |
114 | ||
dce8921b FZ |
115 | static void iothread_instance_finalize(Object *obj) |
116 | { | |
117 | IOThread *iothread = IOTHREAD(obj); | |
118 | ||
82d90705 | 119 | iothread_stop(iothread); |
14a2d118 | 120 | |
15544349 PX |
121 | /* |
122 | * Before glib2 2.33.10, there is a glib2 bug that GSource context | |
123 | * pointer may not be cleared even if the context has already been | |
124 | * destroyed (while it should). Here let's free the AIO context | |
125 | * earlier to bypass that glib bug. | |
126 | * | |
127 | * We can remove this comment after the minimum supported glib2 | |
128 | * version boosts to 2.33.10. Before that, let's free the | |
129 | * GSources first before destroying any GMainContext. | |
130 | */ | |
131 | if (iothread->ctx) { | |
132 | aio_context_unref(iothread->ctx); | |
133 | iothread->ctx = NULL; | |
134 | } | |
5b3ac23f PX |
135 | if (iothread->worker_context) { |
136 | g_main_context_unref(iothread->worker_context); | |
137 | iothread->worker_context = NULL; | |
0bd2d233 PX |
138 | g_main_loop_unref(iothread->main_loop); |
139 | iothread->main_loop = NULL; | |
5b3ac23f | 140 | } |
21c4d15b | 141 | qemu_sem_destroy(&iothread->init_done_sem); |
be8d8537 SH |
142 | } |
143 | ||
b506e0f1 PX |
144 | static void iothread_init_gcontext(IOThread *iothread) |
145 | { | |
146 | GSource *source; | |
147 | ||
148 | iothread->worker_context = g_main_context_new(); | |
149 | source = aio_get_g_source(iothread_get_aio_context(iothread)); | |
150 | g_source_attach(source, iothread->worker_context); | |
151 | g_source_unref(source); | |
0bd2d233 | 152 | iothread->main_loop = g_main_loop_new(iothread->worker_context, TRUE); |
b506e0f1 PX |
153 | } |
154 | ||
be8d8537 SH |
155 | static void iothread_complete(UserCreatable *obj, Error **errp) |
156 | { | |
2f78e491 | 157 | Error *local_error = NULL; |
be8d8537 | 158 | IOThread *iothread = IOTHREAD(obj); |
d21e8776 | 159 | char *name, *thread_name; |
be8d8537 SH |
160 | |
161 | iothread->stopping = false; | |
2362a28e | 162 | iothread->running = true; |
2f78e491 CN |
163 | iothread->ctx = aio_context_new(&local_error); |
164 | if (!iothread->ctx) { | |
165 | error_propagate(errp, local_error); | |
166 | return; | |
167 | } | |
88eb7c29 | 168 | |
b506e0f1 PX |
169 | /* |
170 | * Init one GMainContext for the iothread unconditionally, even if | |
171 | * it's not used | |
172 | */ | |
173 | iothread_init_gcontext(iothread); | |
174 | ||
5e5db499 SH |
175 | aio_context_set_poll_params(iothread->ctx, |
176 | iothread->poll_max_ns, | |
177 | iothread->poll_grow, | |
178 | iothread->poll_shrink, | |
0d9d86fb SH |
179 | &local_error); |
180 | if (local_error) { | |
181 | error_propagate(errp, local_error); | |
182 | aio_context_unref(iothread->ctx); | |
183 | iothread->ctx = NULL; | |
184 | return; | |
185 | } | |
186 | ||
be8d8537 SH |
187 | /* This assumes we are called from a thread with useful CPU affinity for us |
188 | * to inherit. | |
189 | */ | |
d21e8776 PB |
190 | name = object_get_canonical_path_component(OBJECT(obj)); |
191 | thread_name = g_strdup_printf("IO %s", name); | |
192 | qemu_thread_create(&iothread->thread, thread_name, iothread_run, | |
be8d8537 | 193 | iothread, QEMU_THREAD_JOINABLE); |
d21e8776 PB |
194 | g_free(thread_name); |
195 | g_free(name); | |
88eb7c29 SH |
196 | |
197 | /* Wait for initialization to complete */ | |
88eb7c29 | 198 | while (iothread->thread_id == -1) { |
21c4d15b | 199 | qemu_sem_wait(&iothread->init_done_sem); |
88eb7c29 | 200 | } |
be8d8537 SH |
201 | } |
202 | ||
5e5db499 SH |
203 | typedef struct { |
204 | const char *name; | |
205 | ptrdiff_t offset; /* field's byte offset in IOThread struct */ | |
206 | } PollParamInfo; | |
207 | ||
208 | static PollParamInfo poll_max_ns_info = { | |
209 | "poll-max-ns", offsetof(IOThread, poll_max_ns), | |
210 | }; | |
211 | static PollParamInfo poll_grow_info = { | |
212 | "poll-grow", offsetof(IOThread, poll_grow), | |
213 | }; | |
214 | static PollParamInfo poll_shrink_info = { | |
215 | "poll-shrink", offsetof(IOThread, poll_shrink), | |
216 | }; | |
217 | ||
218 | static void iothread_get_poll_param(Object *obj, Visitor *v, | |
0d9d86fb SH |
219 | const char *name, void *opaque, Error **errp) |
220 | { | |
221 | IOThread *iothread = IOTHREAD(obj); | |
5e5db499 SH |
222 | PollParamInfo *info = opaque; |
223 | int64_t *field = (void *)iothread + info->offset; | |
0d9d86fb | 224 | |
5e5db499 | 225 | visit_type_int64(v, name, field, errp); |
0d9d86fb SH |
226 | } |
227 | ||
5e5db499 | 228 | static void iothread_set_poll_param(Object *obj, Visitor *v, |
0d9d86fb SH |
229 | const char *name, void *opaque, Error **errp) |
230 | { | |
231 | IOThread *iothread = IOTHREAD(obj); | |
5e5db499 SH |
232 | PollParamInfo *info = opaque; |
233 | int64_t *field = (void *)iothread + info->offset; | |
0d9d86fb SH |
234 | Error *local_err = NULL; |
235 | int64_t value; | |
236 | ||
237 | visit_type_int64(v, name, &value, &local_err); | |
238 | if (local_err) { | |
239 | goto out; | |
240 | } | |
241 | ||
242 | if (value < 0) { | |
5e5db499 SH |
243 | error_setg(&local_err, "%s value must be in range [0, %"PRId64"]", |
244 | info->name, INT64_MAX); | |
0d9d86fb SH |
245 | goto out; |
246 | } | |
247 | ||
5e5db499 | 248 | *field = value; |
0d9d86fb SH |
249 | |
250 | if (iothread->ctx) { | |
5e5db499 SH |
251 | aio_context_set_poll_params(iothread->ctx, |
252 | iothread->poll_max_ns, | |
253 | iothread->poll_grow, | |
254 | iothread->poll_shrink, | |
255 | &local_err); | |
0d9d86fb SH |
256 | } |
257 | ||
258 | out: | |
259 | error_propagate(errp, local_err); | |
260 | } | |
261 | ||
be8d8537 SH |
262 | static void iothread_class_init(ObjectClass *klass, void *class_data) |
263 | { | |
264 | UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass); | |
265 | ucc->complete = iothread_complete; | |
0d9d86fb SH |
266 | |
267 | object_class_property_add(klass, "poll-max-ns", "int", | |
5e5db499 SH |
268 | iothread_get_poll_param, |
269 | iothread_set_poll_param, | |
270 | NULL, &poll_max_ns_info, &error_abort); | |
271 | object_class_property_add(klass, "poll-grow", "int", | |
272 | iothread_get_poll_param, | |
273 | iothread_set_poll_param, | |
274 | NULL, &poll_grow_info, &error_abort); | |
275 | object_class_property_add(klass, "poll-shrink", "int", | |
276 | iothread_get_poll_param, | |
277 | iothread_set_poll_param, | |
278 | NULL, &poll_shrink_info, &error_abort); | |
be8d8537 SH |
279 | } |
280 | ||
281 | static const TypeInfo iothread_info = { | |
282 | .name = TYPE_IOTHREAD, | |
283 | .parent = TYPE_OBJECT, | |
284 | .class_init = iothread_class_init, | |
285 | .instance_size = sizeof(IOThread), | |
cdd7abfd | 286 | .instance_init = iothread_instance_init, |
be8d8537 SH |
287 | .instance_finalize = iothread_instance_finalize, |
288 | .interfaces = (InterfaceInfo[]) { | |
289 | {TYPE_USER_CREATABLE}, | |
290 | {} | |
291 | }, | |
292 | }; | |
293 | ||
294 | static void iothread_register_types(void) | |
295 | { | |
296 | type_register_static(&iothread_info); | |
297 | } | |
298 | ||
299 | type_init(iothread_register_types) | |
300 | ||
be8d8537 SH |
301 | char *iothread_get_id(IOThread *iothread) |
302 | { | |
303 | return object_get_canonical_path_component(OBJECT(iothread)); | |
304 | } | |
305 | ||
306 | AioContext *iothread_get_aio_context(IOThread *iothread) | |
307 | { | |
308 | return iothread->ctx; | |
309 | } | |
dc3dd0d2 SH |
310 | |
311 | static int query_one_iothread(Object *object, void *opaque) | |
312 | { | |
313 | IOThreadInfoList ***prev = opaque; | |
314 | IOThreadInfoList *elem; | |
315 | IOThreadInfo *info; | |
316 | IOThread *iothread; | |
317 | ||
318 | iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD); | |
319 | if (!iothread) { | |
320 | return 0; | |
321 | } | |
322 | ||
323 | info = g_new0(IOThreadInfo, 1); | |
324 | info->id = iothread_get_id(iothread); | |
325 | info->thread_id = iothread->thread_id; | |
5fc00480 PH |
326 | info->poll_max_ns = iothread->poll_max_ns; |
327 | info->poll_grow = iothread->poll_grow; | |
328 | info->poll_shrink = iothread->poll_shrink; | |
dc3dd0d2 SH |
329 | |
330 | elem = g_new0(IOThreadInfoList, 1); | |
331 | elem->value = info; | |
332 | elem->next = NULL; | |
333 | ||
334 | **prev = elem; | |
335 | *prev = &elem->next; | |
336 | return 0; | |
337 | } | |
338 | ||
339 | IOThreadInfoList *qmp_query_iothreads(Error **errp) | |
340 | { | |
341 | IOThreadInfoList *head = NULL; | |
342 | IOThreadInfoList **prev = &head; | |
bc2256c4 | 343 | Object *container = object_get_objects_root(); |
dc3dd0d2 SH |
344 | |
345 | object_child_foreach(container, query_one_iothread, &prev); | |
346 | return head; | |
347 | } | |
dce8921b | 348 | |
329163cb WY |
349 | GMainContext *iothread_get_g_main_context(IOThread *iothread) |
350 | { | |
b506e0f1 PX |
351 | atomic_set(&iothread->run_gcontext, 1); |
352 | aio_notify(iothread->ctx); | |
329163cb WY |
353 | return iothread->worker_context; |
354 | } | |
0173e21b PX |
355 | |
356 | IOThread *iothread_create(const char *id, Error **errp) | |
357 | { | |
358 | Object *obj; | |
359 | ||
360 | obj = object_new_with_props(TYPE_IOTHREAD, | |
361 | object_get_internal_root(), | |
362 | id, errp, NULL); | |
363 | ||
364 | return IOTHREAD(obj); | |
365 | } | |
366 | ||
367 | void iothread_destroy(IOThread *iothread) | |
368 | { | |
369 | object_unparent(OBJECT(iothread)); | |
370 | } | |
fbcc6923 SH |
371 | |
372 | /* Lookup IOThread by its id. Only finds user-created objects, not internal | |
373 | * iothread_create() objects. */ | |
374 | IOThread *iothread_by_id(const char *id) | |
375 | { | |
376 | return IOTHREAD(object_resolve_path_type(id, TYPE_IOTHREAD, NULL)); | |
377 | } |