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Commit | Line | Data |
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be8d8537 SH |
1 | /* |
2 | * Event loop thread | |
3 | * | |
c3033fd3 | 4 | * Copyright Red Hat Inc., 2013, 2020 |
be8d8537 SH |
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 | 28 | |
8110fa1d EH |
29 | DECLARE_CLASS_CHECKERS(IOThreadClass, IOTHREAD, |
30 | TYPE_IOTHREAD) | |
be8d8537 | 31 | |
90c558be | 32 | #ifdef CONFIG_POSIX |
cdd7abfd SH |
33 | /* Benchmark results from 2016 on NVMe SSD drives show max polling times around |
34 | * 16-32 microseconds yield IOPS improvements for both iodepth=1 and iodepth=32 | |
35 | * workloads. | |
36 | */ | |
37 | #define IOTHREAD_POLL_MAX_NS_DEFAULT 32768ULL | |
90c558be PX |
38 | #else |
39 | #define IOTHREAD_POLL_MAX_NS_DEFAULT 0ULL | |
40 | #endif | |
cdd7abfd | 41 | |
be8d8537 SH |
42 | static void *iothread_run(void *opaque) |
43 | { | |
44 | IOThread *iothread = opaque; | |
45 | ||
ab28bd23 | 46 | rcu_register_thread(); |
b60ec76a PX |
47 | /* |
48 | * g_main_context_push_thread_default() must be called before anything | |
49 | * in this new thread uses glib. | |
50 | */ | |
51 | g_main_context_push_thread_default(iothread->worker_context); | |
5f50be9b | 52 | qemu_set_current_aio_context(iothread->ctx); |
88eb7c29 | 53 | iothread->thread_id = qemu_get_thread_id(); |
21c4d15b | 54 | qemu_sem_post(&iothread->init_done_sem); |
88eb7c29 | 55 | |
2362a28e | 56 | while (iothread->running) { |
6ca20620 PX |
57 | /* |
58 | * Note: from functional-wise the g_main_loop_run() below can | |
59 | * already cover the aio_poll() events, but we can't run the | |
60 | * main loop unconditionally because explicit aio_poll() here | |
61 | * is faster than g_main_loop_run() when we do not need the | |
62 | * gcontext at all (e.g., pure block layer iothreads). In | |
63 | * other words, when we want to run the gcontext with the | |
64 | * iothread we need to pay some performance for functionality. | |
65 | */ | |
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 | */ | |
d73415a3 | 72 | if (iothread->running && qatomic_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 | 111 | /* By default, we don't run gcontext */ |
d73415a3 | 112 | qatomic_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 | ||
1793ad02 SG |
155 | static void iothread_set_aio_context_params(IOThread *iothread, Error **errp) |
156 | { | |
157 | ERRP_GUARD(); | |
158 | ||
159 | aio_context_set_poll_params(iothread->ctx, | |
160 | iothread->poll_max_ns, | |
161 | iothread->poll_grow, | |
162 | iothread->poll_shrink, | |
163 | errp); | |
164 | if (*errp) { | |
165 | return; | |
166 | } | |
167 | ||
168 | aio_context_set_aio_params(iothread->ctx, | |
169 | iothread->aio_max_batch, | |
170 | errp); | |
171 | } | |
172 | ||
be8d8537 SH |
173 | static void iothread_complete(UserCreatable *obj, Error **errp) |
174 | { | |
2f78e491 | 175 | Error *local_error = NULL; |
be8d8537 | 176 | IOThread *iothread = IOTHREAD(obj); |
7a309cc9 | 177 | char *thread_name; |
be8d8537 SH |
178 | |
179 | iothread->stopping = false; | |
2362a28e | 180 | iothread->running = true; |
668f62ec | 181 | iothread->ctx = aio_context_new(errp); |
2f78e491 | 182 | if (!iothread->ctx) { |
2f78e491 CN |
183 | return; |
184 | } | |
88eb7c29 | 185 | |
b506e0f1 PX |
186 | /* |
187 | * Init one GMainContext for the iothread unconditionally, even if | |
188 | * it's not used | |
189 | */ | |
190 | iothread_init_gcontext(iothread); | |
191 | ||
1793ad02 | 192 | iothread_set_aio_context_params(iothread, &local_error); |
0d9d86fb SH |
193 | if (local_error) { |
194 | error_propagate(errp, local_error); | |
195 | aio_context_unref(iothread->ctx); | |
196 | iothread->ctx = NULL; | |
197 | return; | |
198 | } | |
199 | ||
be8d8537 SH |
200 | /* This assumes we are called from a thread with useful CPU affinity for us |
201 | * to inherit. | |
202 | */ | |
7a309cc9 MA |
203 | thread_name = g_strdup_printf("IO %s", |
204 | object_get_canonical_path_component(OBJECT(obj))); | |
d21e8776 | 205 | qemu_thread_create(&iothread->thread, thread_name, iothread_run, |
be8d8537 | 206 | iothread, QEMU_THREAD_JOINABLE); |
d21e8776 | 207 | g_free(thread_name); |
88eb7c29 SH |
208 | |
209 | /* Wait for initialization to complete */ | |
88eb7c29 | 210 | while (iothread->thread_id == -1) { |
21c4d15b | 211 | qemu_sem_wait(&iothread->init_done_sem); |
88eb7c29 | 212 | } |
be8d8537 SH |
213 | } |
214 | ||
5e5db499 SH |
215 | typedef struct { |
216 | const char *name; | |
217 | ptrdiff_t offset; /* field's byte offset in IOThread struct */ | |
218 | } PollParamInfo; | |
219 | ||
220 | static PollParamInfo poll_max_ns_info = { | |
221 | "poll-max-ns", offsetof(IOThread, poll_max_ns), | |
222 | }; | |
223 | static PollParamInfo poll_grow_info = { | |
224 | "poll-grow", offsetof(IOThread, poll_grow), | |
225 | }; | |
226 | static PollParamInfo poll_shrink_info = { | |
227 | "poll-shrink", offsetof(IOThread, poll_shrink), | |
228 | }; | |
1793ad02 SG |
229 | static PollParamInfo aio_max_batch_info = { |
230 | "aio-max-batch", offsetof(IOThread, aio_max_batch), | |
231 | }; | |
5e5db499 | 232 | |
0445409d | 233 | static void iothread_get_param(Object *obj, Visitor *v, |
0d9d86fb SH |
234 | const char *name, void *opaque, Error **errp) |
235 | { | |
236 | IOThread *iothread = IOTHREAD(obj); | |
5e5db499 SH |
237 | PollParamInfo *info = opaque; |
238 | int64_t *field = (void *)iothread + info->offset; | |
0d9d86fb | 239 | |
5e5db499 | 240 | visit_type_int64(v, name, field, errp); |
0d9d86fb SH |
241 | } |
242 | ||
0445409d | 243 | static bool iothread_set_param(Object *obj, Visitor *v, |
0d9d86fb SH |
244 | const char *name, void *opaque, Error **errp) |
245 | { | |
246 | IOThread *iothread = IOTHREAD(obj); | |
5e5db499 SH |
247 | PollParamInfo *info = opaque; |
248 | int64_t *field = (void *)iothread + info->offset; | |
0d9d86fb SH |
249 | int64_t value; |
250 | ||
668f62ec | 251 | if (!visit_type_int64(v, name, &value, errp)) { |
0445409d | 252 | return false; |
0d9d86fb SH |
253 | } |
254 | ||
255 | if (value < 0) { | |
dcfe4805 | 256 | error_setg(errp, "%s value must be in range [0, %" PRId64 "]", |
5e5db499 | 257 | info->name, INT64_MAX); |
0445409d | 258 | return false; |
0d9d86fb SH |
259 | } |
260 | ||
5e5db499 | 261 | *field = value; |
0d9d86fb | 262 | |
0445409d SG |
263 | return true; |
264 | } | |
265 | ||
266 | static void iothread_get_poll_param(Object *obj, Visitor *v, | |
267 | const char *name, void *opaque, Error **errp) | |
268 | { | |
269 | ||
270 | iothread_get_param(obj, v, name, opaque, errp); | |
271 | } | |
272 | ||
273 | static void iothread_set_poll_param(Object *obj, Visitor *v, | |
274 | const char *name, void *opaque, Error **errp) | |
275 | { | |
276 | IOThread *iothread = IOTHREAD(obj); | |
277 | ||
278 | if (!iothread_set_param(obj, v, name, opaque, errp)) { | |
279 | return; | |
280 | } | |
281 | ||
0d9d86fb | 282 | if (iothread->ctx) { |
5e5db499 SH |
283 | aio_context_set_poll_params(iothread->ctx, |
284 | iothread->poll_max_ns, | |
285 | iothread->poll_grow, | |
286 | iothread->poll_shrink, | |
dcfe4805 | 287 | errp); |
0d9d86fb | 288 | } |
0d9d86fb SH |
289 | } |
290 | ||
1793ad02 SG |
291 | static void iothread_get_aio_param(Object *obj, Visitor *v, |
292 | const char *name, void *opaque, Error **errp) | |
293 | { | |
294 | ||
295 | iothread_get_param(obj, v, name, opaque, errp); | |
296 | } | |
297 | ||
298 | static void iothread_set_aio_param(Object *obj, Visitor *v, | |
299 | const char *name, void *opaque, Error **errp) | |
300 | { | |
301 | IOThread *iothread = IOTHREAD(obj); | |
302 | ||
303 | if (!iothread_set_param(obj, v, name, opaque, errp)) { | |
304 | return; | |
305 | } | |
306 | ||
307 | if (iothread->ctx) { | |
308 | aio_context_set_aio_params(iothread->ctx, | |
309 | iothread->aio_max_batch, | |
310 | errp); | |
311 | } | |
312 | } | |
313 | ||
be8d8537 SH |
314 | static void iothread_class_init(ObjectClass *klass, void *class_data) |
315 | { | |
316 | UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass); | |
317 | ucc->complete = iothread_complete; | |
0d9d86fb SH |
318 | |
319 | object_class_property_add(klass, "poll-max-ns", "int", | |
5e5db499 SH |
320 | iothread_get_poll_param, |
321 | iothread_set_poll_param, | |
d2623129 | 322 | NULL, &poll_max_ns_info); |
5e5db499 SH |
323 | object_class_property_add(klass, "poll-grow", "int", |
324 | iothread_get_poll_param, | |
325 | iothread_set_poll_param, | |
d2623129 | 326 | NULL, &poll_grow_info); |
5e5db499 SH |
327 | object_class_property_add(klass, "poll-shrink", "int", |
328 | iothread_get_poll_param, | |
329 | iothread_set_poll_param, | |
d2623129 | 330 | NULL, &poll_shrink_info); |
1793ad02 SG |
331 | object_class_property_add(klass, "aio-max-batch", "int", |
332 | iothread_get_aio_param, | |
333 | iothread_set_aio_param, | |
334 | NULL, &aio_max_batch_info); | |
be8d8537 SH |
335 | } |
336 | ||
337 | static const TypeInfo iothread_info = { | |
338 | .name = TYPE_IOTHREAD, | |
339 | .parent = TYPE_OBJECT, | |
340 | .class_init = iothread_class_init, | |
341 | .instance_size = sizeof(IOThread), | |
cdd7abfd | 342 | .instance_init = iothread_instance_init, |
be8d8537 SH |
343 | .instance_finalize = iothread_instance_finalize, |
344 | .interfaces = (InterfaceInfo[]) { | |
345 | {TYPE_USER_CREATABLE}, | |
346 | {} | |
347 | }, | |
348 | }; | |
349 | ||
350 | static void iothread_register_types(void) | |
351 | { | |
352 | type_register_static(&iothread_info); | |
353 | } | |
354 | ||
355 | type_init(iothread_register_types) | |
356 | ||
be8d8537 SH |
357 | char *iothread_get_id(IOThread *iothread) |
358 | { | |
7a309cc9 | 359 | return g_strdup(object_get_canonical_path_component(OBJECT(iothread))); |
be8d8537 SH |
360 | } |
361 | ||
362 | AioContext *iothread_get_aio_context(IOThread *iothread) | |
363 | { | |
364 | return iothread->ctx; | |
365 | } | |
dc3dd0d2 SH |
366 | |
367 | static int query_one_iothread(Object *object, void *opaque) | |
368 | { | |
c3033fd3 | 369 | IOThreadInfoList ***tail = opaque; |
dc3dd0d2 SH |
370 | IOThreadInfo *info; |
371 | IOThread *iothread; | |
372 | ||
373 | iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD); | |
374 | if (!iothread) { | |
375 | return 0; | |
376 | } | |
377 | ||
378 | info = g_new0(IOThreadInfo, 1); | |
379 | info->id = iothread_get_id(iothread); | |
380 | info->thread_id = iothread->thread_id; | |
5fc00480 PH |
381 | info->poll_max_ns = iothread->poll_max_ns; |
382 | info->poll_grow = iothread->poll_grow; | |
383 | info->poll_shrink = iothread->poll_shrink; | |
1793ad02 | 384 | info->aio_max_batch = iothread->aio_max_batch; |
dc3dd0d2 | 385 | |
c3033fd3 | 386 | QAPI_LIST_APPEND(*tail, info); |
dc3dd0d2 SH |
387 | return 0; |
388 | } | |
389 | ||
390 | IOThreadInfoList *qmp_query_iothreads(Error **errp) | |
391 | { | |
392 | IOThreadInfoList *head = NULL; | |
393 | IOThreadInfoList **prev = &head; | |
bc2256c4 | 394 | Object *container = object_get_objects_root(); |
dc3dd0d2 SH |
395 | |
396 | object_child_foreach(container, query_one_iothread, &prev); | |
397 | return head; | |
398 | } | |
dce8921b | 399 | |
329163cb WY |
400 | GMainContext *iothread_get_g_main_context(IOThread *iothread) |
401 | { | |
d73415a3 | 402 | qatomic_set(&iothread->run_gcontext, 1); |
b506e0f1 | 403 | aio_notify(iothread->ctx); |
329163cb WY |
404 | return iothread->worker_context; |
405 | } | |
0173e21b PX |
406 | |
407 | IOThread *iothread_create(const char *id, Error **errp) | |
408 | { | |
409 | Object *obj; | |
410 | ||
411 | obj = object_new_with_props(TYPE_IOTHREAD, | |
412 | object_get_internal_root(), | |
413 | id, errp, NULL); | |
414 | ||
415 | return IOTHREAD(obj); | |
416 | } | |
417 | ||
418 | void iothread_destroy(IOThread *iothread) | |
419 | { | |
420 | object_unparent(OBJECT(iothread)); | |
421 | } | |
fbcc6923 SH |
422 | |
423 | /* Lookup IOThread by its id. Only finds user-created objects, not internal | |
424 | * iothread_create() objects. */ | |
425 | IOThread *iothread_by_id(const char *id) | |
426 | { | |
427 | return IOTHREAD(object_resolve_path_type(id, TYPE_IOTHREAD, NULL)); | |
428 | } | |
ad22c308 EU |
429 | |
430 | bool qemu_in_iothread(void) | |
431 | { | |
432 | return qemu_get_current_aio_context() == qemu_get_aio_context() ? | |
433 | false : true; | |
434 | } |