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Stefan Hajnoczibe8d8532014-03-03 11:30:05 +01001/*
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
Peter Maydelld38ea872016-01-29 17:50:05 +000014#include "qemu/osdep.h"
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010015#include "qom/object.h"
16#include "qom/object_interfaces.h"
17#include "qemu/module.h"
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010018#include "block/aio.h"
Paolo Bonzinid16341f2016-10-27 12:49:00 +020019#include "block/block.h"
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010020#include "sysemu/iothread.h"
Markus Armbrustere688df62018-02-01 12:18:31 +010021#include "qapi/error.h"
Markus Armbruster112ed242018-02-26 17:13:27 -060022#include "qapi/qapi-commands-misc.h"
Chrysostomos Nanakos2f78e492014-09-18 14:30:49 +030023#include "qemu/error-report.h"
Paolo Bonziniab28bd22015-07-09 08:55:38 +020024#include "qemu/rcu.h"
Paolo Bonzinie4370162016-10-27 12:48:59 +020025#include "qemu/main-loop.h"
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010026
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010027typedef ObjectClass IOThreadClass;
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010028
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
Peter Xu90c558b2018-03-22 16:56:30 +080034#ifdef CONFIG_POSIX
Stefan Hajnoczicdd7abf2017-01-26 17:01:19 +000035/* 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
Peter Xu90c558b2018-03-22 16:56:30 +080040#else
41#define IOTHREAD_POLL_MAX_NS_DEFAULT 0ULL
42#endif
Stefan Hajnoczicdd7abf2017-01-26 17:01:19 +000043
Paolo Bonzinie4370162016-10-27 12:48:59 +020044static __thread IOThread *my_iothread;
45
46AioContext *qemu_get_current_aio_context(void)
47{
48 return my_iothread ? my_iothread->ctx : qemu_get_aio_context();
49}
50
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010051static void *iothread_run(void *opaque)
52{
53 IOThread *iothread = opaque;
54
Paolo Bonziniab28bd22015-07-09 08:55:38 +020055 rcu_register_thread();
56
Paolo Bonzinie4370162016-10-27 12:48:59 +020057 my_iothread = iothread;
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +010058 qemu_mutex_lock(&iothread->init_done_lock);
59 iothread->thread_id = qemu_get_thread_id();
60 qemu_cond_signal(&iothread->init_done_cond);
61 qemu_mutex_unlock(&iothread->init_done_lock);
62
Stefan Hajnoczi2362a282017-12-07 20:13:19 +000063 while (iothread->running) {
Paolo Bonzini65c1b5b2016-10-27 12:49:06 +020064 aio_poll(iothread->ctx, true);
Wang Yong329163c2017-08-29 15:22:37 +080065
66 if (atomic_read(&iothread->worker_context)) {
67 GMainLoop *loop;
68
69 g_main_context_push_thread_default(iothread->worker_context);
70 iothread->main_loop =
71 g_main_loop_new(iothread->worker_context, TRUE);
72 loop = iothread->main_loop;
73
74 g_main_loop_run(iothread->main_loop);
75 iothread->main_loop = NULL;
76 g_main_loop_unref(loop);
77
78 g_main_context_pop_thread_default(iothread->worker_context);
Wang Yong329163c2017-08-29 15:22:37 +080079 }
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010080 }
Paolo Bonziniab28bd22015-07-09 08:55:38 +020081
82 rcu_unregister_thread();
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010083 return NULL;
84}
85
Stefan Hajnoczi2362a282017-12-07 20:13:19 +000086/* Runs in iothread_run() thread */
87static void iothread_stop_bh(void *opaque)
88{
89 IOThread *iothread = opaque;
90
91 iothread->running = false; /* stop iothread_run() */
92
93 if (iothread->main_loop) {
94 g_main_loop_quit(iothread->main_loop);
95 }
96}
97
Peter Xu82d90702017-09-28 10:59:56 +080098void iothread_stop(IOThread *iothread)
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010099{
Peter Xu82d90702017-09-28 10:59:56 +0800100 if (!iothread->ctx || iothread->stopping) {
101 return;
Chrysostomos Nanakos2f78e492014-09-18 14:30:49 +0300102 }
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100103 iothread->stopping = true;
Stefan Hajnoczi2362a282017-12-07 20:13:19 +0000104 aio_bh_schedule_oneshot(iothread->ctx, iothread_stop_bh, iothread);
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100105 qemu_thread_join(&iothread->thread);
Peter Xu82d90702017-09-28 10:59:56 +0800106}
107
Stefan Hajnoczicdd7abf2017-01-26 17:01:19 +0000108static void iothread_instance_init(Object *obj)
109{
110 IOThread *iothread = IOTHREAD(obj);
111
112 iothread->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT;
113}
114
Fam Zhengdce89212016-09-08 17:28:51 +0800115static void iothread_instance_finalize(Object *obj)
116{
117 IOThread *iothread = IOTHREAD(obj);
118
Peter Xu82d90702017-09-28 10:59:56 +0800119 iothread_stop(iothread);
Peter Xu15544342018-04-09 16:39:56 +0800120 /*
121 * Before glib2 2.33.10, there is a glib2 bug that GSource context
122 * pointer may not be cleared even if the context has already been
123 * destroyed (while it should). Here let's free the AIO context
124 * earlier to bypass that glib bug.
125 *
126 * We can remove this comment after the minimum supported glib2
127 * version boosts to 2.33.10. Before that, let's free the
128 * GSources first before destroying any GMainContext.
129 */
130 if (iothread->ctx) {
131 aio_context_unref(iothread->ctx);
132 iothread->ctx = NULL;
133 }
Peter Xu5b3ac232017-09-28 10:59:57 +0800134 if (iothread->worker_context) {
135 g_main_context_unref(iothread->worker_context);
136 iothread->worker_context = NULL;
137 }
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +0100138 qemu_cond_destroy(&iothread->init_done_cond);
139 qemu_mutex_destroy(&iothread->init_done_lock);
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100140}
141
142static void iothread_complete(UserCreatable *obj, Error **errp)
143{
Chrysostomos Nanakos2f78e492014-09-18 14:30:49 +0300144 Error *local_error = NULL;
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100145 IOThread *iothread = IOTHREAD(obj);
Paolo Bonzinid21e8772015-11-24 14:46:44 +0100146 char *name, *thread_name;
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100147
148 iothread->stopping = false;
Stefan Hajnoczi2362a282017-12-07 20:13:19 +0000149 iothread->running = true;
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +0100150 iothread->thread_id = -1;
Chrysostomos Nanakos2f78e492014-09-18 14:30:49 +0300151 iothread->ctx = aio_context_new(&local_error);
152 if (!iothread->ctx) {
153 error_propagate(errp, local_error);
154 return;
155 }
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +0100156
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000157 aio_context_set_poll_params(iothread->ctx,
158 iothread->poll_max_ns,
159 iothread->poll_grow,
160 iothread->poll_shrink,
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000161 &local_error);
162 if (local_error) {
163 error_propagate(errp, local_error);
164 aio_context_unref(iothread->ctx);
165 iothread->ctx = NULL;
166 return;
167 }
168
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +0100169 qemu_mutex_init(&iothread->init_done_lock);
170 qemu_cond_init(&iothread->init_done_cond);
Wang Yong329163c2017-08-29 15:22:37 +0800171 iothread->once = (GOnce) G_ONCE_INIT;
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100172
173 /* This assumes we are called from a thread with useful CPU affinity for us
174 * to inherit.
175 */
Paolo Bonzinid21e8772015-11-24 14:46:44 +0100176 name = object_get_canonical_path_component(OBJECT(obj));
177 thread_name = g_strdup_printf("IO %s", name);
178 qemu_thread_create(&iothread->thread, thread_name, iothread_run,
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100179 iothread, QEMU_THREAD_JOINABLE);
Paolo Bonzinid21e8772015-11-24 14:46:44 +0100180 g_free(thread_name);
181 g_free(name);
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +0100182
183 /* Wait for initialization to complete */
184 qemu_mutex_lock(&iothread->init_done_lock);
185 while (iothread->thread_id == -1) {
186 qemu_cond_wait(&iothread->init_done_cond,
187 &iothread->init_done_lock);
188 }
189 qemu_mutex_unlock(&iothread->init_done_lock);
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100190}
191
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000192typedef struct {
193 const char *name;
194 ptrdiff_t offset; /* field's byte offset in IOThread struct */
195} PollParamInfo;
196
197static PollParamInfo poll_max_ns_info = {
198 "poll-max-ns", offsetof(IOThread, poll_max_ns),
199};
200static PollParamInfo poll_grow_info = {
201 "poll-grow", offsetof(IOThread, poll_grow),
202};
203static PollParamInfo poll_shrink_info = {
204 "poll-shrink", offsetof(IOThread, poll_shrink),
205};
206
207static void iothread_get_poll_param(Object *obj, Visitor *v,
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000208 const char *name, void *opaque, Error **errp)
209{
210 IOThread *iothread = IOTHREAD(obj);
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000211 PollParamInfo *info = opaque;
212 int64_t *field = (void *)iothread + info->offset;
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000213
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000214 visit_type_int64(v, name, field, errp);
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000215}
216
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000217static void iothread_set_poll_param(Object *obj, Visitor *v,
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000218 const char *name, void *opaque, Error **errp)
219{
220 IOThread *iothread = IOTHREAD(obj);
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000221 PollParamInfo *info = opaque;
222 int64_t *field = (void *)iothread + info->offset;
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000223 Error *local_err = NULL;
224 int64_t value;
225
226 visit_type_int64(v, name, &value, &local_err);
227 if (local_err) {
228 goto out;
229 }
230
231 if (value < 0) {
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000232 error_setg(&local_err, "%s value must be in range [0, %"PRId64"]",
233 info->name, INT64_MAX);
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000234 goto out;
235 }
236
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000237 *field = value;
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000238
239 if (iothread->ctx) {
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000240 aio_context_set_poll_params(iothread->ctx,
241 iothread->poll_max_ns,
242 iothread->poll_grow,
243 iothread->poll_shrink,
244 &local_err);
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000245 }
246
247out:
248 error_propagate(errp, local_err);
249}
250
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100251static void iothread_class_init(ObjectClass *klass, void *class_data)
252{
253 UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
254 ucc->complete = iothread_complete;
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000255
256 object_class_property_add(klass, "poll-max-ns", "int",
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000257 iothread_get_poll_param,
258 iothread_set_poll_param,
259 NULL, &poll_max_ns_info, &error_abort);
260 object_class_property_add(klass, "poll-grow", "int",
261 iothread_get_poll_param,
262 iothread_set_poll_param,
263 NULL, &poll_grow_info, &error_abort);
264 object_class_property_add(klass, "poll-shrink", "int",
265 iothread_get_poll_param,
266 iothread_set_poll_param,
267 NULL, &poll_shrink_info, &error_abort);
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100268}
269
270static const TypeInfo iothread_info = {
271 .name = TYPE_IOTHREAD,
272 .parent = TYPE_OBJECT,
273 .class_init = iothread_class_init,
274 .instance_size = sizeof(IOThread),
Stefan Hajnoczicdd7abf2017-01-26 17:01:19 +0000275 .instance_init = iothread_instance_init,
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100276 .instance_finalize = iothread_instance_finalize,
277 .interfaces = (InterfaceInfo[]) {
278 {TYPE_USER_CREATABLE},
279 {}
280 },
281};
282
283static void iothread_register_types(void)
284{
285 type_register_static(&iothread_info);
286}
287
288type_init(iothread_register_types)
289
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100290char *iothread_get_id(IOThread *iothread)
291{
292 return object_get_canonical_path_component(OBJECT(iothread));
293}
294
295AioContext *iothread_get_aio_context(IOThread *iothread)
296{
297 return iothread->ctx;
298}
Stefan Hajnoczidc3dd0d2014-02-27 11:48:42 +0100299
300static int query_one_iothread(Object *object, void *opaque)
301{
302 IOThreadInfoList ***prev = opaque;
303 IOThreadInfoList *elem;
304 IOThreadInfo *info;
305 IOThread *iothread;
306
307 iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
308 if (!iothread) {
309 return 0;
310 }
311
312 info = g_new0(IOThreadInfo, 1);
313 info->id = iothread_get_id(iothread);
314 info->thread_id = iothread->thread_id;
Pavel Hrdina5fc00482017-02-10 10:41:17 +0100315 info->poll_max_ns = iothread->poll_max_ns;
316 info->poll_grow = iothread->poll_grow;
317 info->poll_shrink = iothread->poll_shrink;
Stefan Hajnoczidc3dd0d2014-02-27 11:48:42 +0100318
319 elem = g_new0(IOThreadInfoList, 1);
320 elem->value = info;
321 elem->next = NULL;
322
323 **prev = elem;
324 *prev = &elem->next;
325 return 0;
326}
327
328IOThreadInfoList *qmp_query_iothreads(Error **errp)
329{
330 IOThreadInfoList *head = NULL;
331 IOThreadInfoList **prev = &head;
Daniel P. Berrangebc2256c2015-05-13 17:14:05 +0100332 Object *container = object_get_objects_root();
Stefan Hajnoczidc3dd0d2014-02-27 11:48:42 +0100333
334 object_child_foreach(container, query_one_iothread, &prev);
335 return head;
336}
Fam Zhengdce89212016-09-08 17:28:51 +0800337
Wang Yong329163c2017-08-29 15:22:37 +0800338static gpointer iothread_g_main_context_init(gpointer opaque)
339{
340 AioContext *ctx;
341 IOThread *iothread = opaque;
342 GSource *source;
343
344 iothread->worker_context = g_main_context_new();
345
346 ctx = iothread_get_aio_context(iothread);
347 source = aio_get_g_source(ctx);
348 g_source_attach(source, iothread->worker_context);
349 g_source_unref(source);
350
351 aio_notify(iothread->ctx);
352 return NULL;
353}
354
355GMainContext *iothread_get_g_main_context(IOThread *iothread)
356{
357 g_once(&iothread->once, iothread_g_main_context_init, iothread);
358
359 return iothread->worker_context;
360}
Peter Xu0173e212017-09-28 10:59:55 +0800361
362IOThread *iothread_create(const char *id, Error **errp)
363{
364 Object *obj;
365
366 obj = object_new_with_props(TYPE_IOTHREAD,
367 object_get_internal_root(),
368 id, errp, NULL);
369
370 return IOTHREAD(obj);
371}
372
373void iothread_destroy(IOThread *iothread)
374{
375 object_unparent(OBJECT(iothread));
376}
Stefan Hajnoczifbcc6922017-12-06 14:45:48 +0000377
378/* Lookup IOThread by its id. Only finds user-created objects, not internal
379 * iothread_create() objects. */
380IOThread *iothread_by_id(const char *id)
381{
382 return IOTHREAD(object_resolve_path_type(id, TYPE_IOTHREAD, NULL));
383}