blob: 263ec6e5bca817b4baeed3d8433dfca6ccf0cbfe [file] [log] [blame]
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();
Peter Xub60ec762019-03-06 19:55:31 +080056 /*
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);
Paolo Bonzinie4370162016-10-27 12:48:59 +020061 my_iothread = iothread;
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +010062 iothread->thread_id = qemu_get_thread_id();
Peter Xu21c4d152019-03-06 19:55:28 +080063 qemu_sem_post(&iothread->init_done_sem);
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +010064
Stefan Hajnoczi2362a282017-12-07 20:13:19 +000065 while (iothread->running) {
Peter Xu6ca20622019-03-06 19:55:32 +080066 /*
67 * Note: from functional-wise the g_main_loop_run() below can
68 * already cover the aio_poll() events, but we can't run the
69 * main loop unconditionally because explicit aio_poll() here
70 * is faster than g_main_loop_run() when we do not need the
71 * gcontext at all (e.g., pure block layer iothreads). In
72 * other words, when we want to run the gcontext with the
73 * iothread we need to pay some performance for functionality.
74 */
Paolo Bonzini65c1b5b2016-10-27 12:49:06 +020075 aio_poll(iothread->ctx, true);
Wang Yong329163c2017-08-29 15:22:37 +080076
Peter Xu6c953632019-01-29 13:14:32 +080077 /*
78 * We must check the running state again in case it was
79 * changed in previous aio_poll()
80 */
Peter Xub506e0f2019-03-06 19:55:29 +080081 if (iothread->running && atomic_read(&iothread->run_gcontext)) {
Wang Yong329163c2017-08-29 15:22:37 +080082 g_main_loop_run(iothread->main_loop);
Wang Yong329163c2017-08-29 15:22:37 +080083 }
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010084 }
Paolo Bonziniab28bd22015-07-09 08:55:38 +020085
Peter Xub60ec762019-03-06 19:55:31 +080086 g_main_context_pop_thread_default(iothread->worker_context);
Paolo Bonziniab28bd22015-07-09 08:55:38 +020087 rcu_unregister_thread();
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +010088 return NULL;
89}
90
Stefan Hajnoczi2362a282017-12-07 20:13:19 +000091/* Runs in iothread_run() thread */
92static void iothread_stop_bh(void *opaque)
93{
94 IOThread *iothread = opaque;
95
96 iothread->running = false; /* stop iothread_run() */
97
98 if (iothread->main_loop) {
99 g_main_loop_quit(iothread->main_loop);
100 }
101}
102
Peter Xu82d90702017-09-28 10:59:56 +0800103void iothread_stop(IOThread *iothread)
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100104{
Peter Xu82d90702017-09-28 10:59:56 +0800105 if (!iothread->ctx || iothread->stopping) {
106 return;
Chrysostomos Nanakos2f78e492014-09-18 14:30:49 +0300107 }
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100108 iothread->stopping = true;
Stefan Hajnoczi2362a282017-12-07 20:13:19 +0000109 aio_bh_schedule_oneshot(iothread->ctx, iothread_stop_bh, iothread);
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100110 qemu_thread_join(&iothread->thread);
Peter Xu82d90702017-09-28 10:59:56 +0800111}
112
Stefan Hajnoczicdd7abf2017-01-26 17:01:19 +0000113static void iothread_instance_init(Object *obj)
114{
115 IOThread *iothread = IOTHREAD(obj);
116
117 iothread->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT;
Marc-André Lureau14a2d112018-08-21 12:07:16 +0200118 iothread->thread_id = -1;
Peter Xu21c4d152019-03-06 19:55:28 +0800119 qemu_sem_init(&iothread->init_done_sem, 0);
Peter Xub506e0f2019-03-06 19:55:29 +0800120 /* By default, we don't run gcontext */
121 atomic_set(&iothread->run_gcontext, 0);
Stefan Hajnoczicdd7abf2017-01-26 17:01:19 +0000122}
123
Fam Zhengdce89212016-09-08 17:28:51 +0800124static void iothread_instance_finalize(Object *obj)
125{
126 IOThread *iothread = IOTHREAD(obj);
127
Peter Xu82d90702017-09-28 10:59:56 +0800128 iothread_stop(iothread);
Marc-André Lureau14a2d112018-08-21 12:07:16 +0200129
Peter Xu15544342018-04-09 16:39:56 +0800130 /*
131 * Before glib2 2.33.10, there is a glib2 bug that GSource context
132 * pointer may not be cleared even if the context has already been
133 * destroyed (while it should). Here let's free the AIO context
134 * earlier to bypass that glib bug.
135 *
136 * We can remove this comment after the minimum supported glib2
137 * version boosts to 2.33.10. Before that, let's free the
138 * GSources first before destroying any GMainContext.
139 */
140 if (iothread->ctx) {
141 aio_context_unref(iothread->ctx);
142 iothread->ctx = NULL;
143 }
Peter Xu5b3ac232017-09-28 10:59:57 +0800144 if (iothread->worker_context) {
145 g_main_context_unref(iothread->worker_context);
146 iothread->worker_context = NULL;
Peter Xu0bd2d232019-03-06 19:55:30 +0800147 g_main_loop_unref(iothread->main_loop);
148 iothread->main_loop = NULL;
Peter Xu5b3ac232017-09-28 10:59:57 +0800149 }
Peter Xu21c4d152019-03-06 19:55:28 +0800150 qemu_sem_destroy(&iothread->init_done_sem);
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100151}
152
Peter Xub506e0f2019-03-06 19:55:29 +0800153static void iothread_init_gcontext(IOThread *iothread)
154{
155 GSource *source;
156
157 iothread->worker_context = g_main_context_new();
158 source = aio_get_g_source(iothread_get_aio_context(iothread));
159 g_source_attach(source, iothread->worker_context);
160 g_source_unref(source);
Peter Xu0bd2d232019-03-06 19:55:30 +0800161 iothread->main_loop = g_main_loop_new(iothread->worker_context, TRUE);
Peter Xub506e0f2019-03-06 19:55:29 +0800162}
163
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100164static void iothread_complete(UserCreatable *obj, Error **errp)
165{
Chrysostomos Nanakos2f78e492014-09-18 14:30:49 +0300166 Error *local_error = NULL;
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100167 IOThread *iothread = IOTHREAD(obj);
Markus Armbruster7a309cc2020-07-14 18:02:00 +0200168 char *thread_name;
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100169
170 iothread->stopping = false;
Stefan Hajnoczi2362a282017-12-07 20:13:19 +0000171 iothread->running = true;
Markus Armbruster668f62e2020-07-07 18:06:02 +0200172 iothread->ctx = aio_context_new(errp);
Chrysostomos Nanakos2f78e492014-09-18 14:30:49 +0300173 if (!iothread->ctx) {
Chrysostomos Nanakos2f78e492014-09-18 14:30:49 +0300174 return;
175 }
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +0100176
Peter Xub506e0f2019-03-06 19:55:29 +0800177 /*
178 * Init one GMainContext for the iothread unconditionally, even if
179 * it's not used
180 */
181 iothread_init_gcontext(iothread);
182
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000183 aio_context_set_poll_params(iothread->ctx,
184 iothread->poll_max_ns,
185 iothread->poll_grow,
186 iothread->poll_shrink,
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000187 &local_error);
188 if (local_error) {
189 error_propagate(errp, local_error);
190 aio_context_unref(iothread->ctx);
191 iothread->ctx = NULL;
192 return;
193 }
194
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100195 /* This assumes we are called from a thread with useful CPU affinity for us
196 * to inherit.
197 */
Markus Armbruster7a309cc2020-07-14 18:02:00 +0200198 thread_name = g_strdup_printf("IO %s",
199 object_get_canonical_path_component(OBJECT(obj)));
Paolo Bonzinid21e8772015-11-24 14:46:44 +0100200 qemu_thread_create(&iothread->thread, thread_name, iothread_run,
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100201 iothread, QEMU_THREAD_JOINABLE);
Paolo Bonzinid21e8772015-11-24 14:46:44 +0100202 g_free(thread_name);
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +0100203
204 /* Wait for initialization to complete */
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +0100205 while (iothread->thread_id == -1) {
Peter Xu21c4d152019-03-06 19:55:28 +0800206 qemu_sem_wait(&iothread->init_done_sem);
Stefan Hajnoczi88eb7c22014-02-27 11:48:41 +0100207 }
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100208}
209
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000210typedef struct {
211 const char *name;
212 ptrdiff_t offset; /* field's byte offset in IOThread struct */
213} PollParamInfo;
214
215static PollParamInfo poll_max_ns_info = {
216 "poll-max-ns", offsetof(IOThread, poll_max_ns),
217};
218static PollParamInfo poll_grow_info = {
219 "poll-grow", offsetof(IOThread, poll_grow),
220};
221static PollParamInfo poll_shrink_info = {
222 "poll-shrink", offsetof(IOThread, poll_shrink),
223};
224
225static void iothread_get_poll_param(Object *obj, Visitor *v,
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000226 const char *name, void *opaque, Error **errp)
227{
228 IOThread *iothread = IOTHREAD(obj);
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000229 PollParamInfo *info = opaque;
230 int64_t *field = (void *)iothread + info->offset;
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000231
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000232 visit_type_int64(v, name, field, errp);
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000233}
234
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000235static void iothread_set_poll_param(Object *obj, Visitor *v,
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000236 const char *name, void *opaque, Error **errp)
237{
238 IOThread *iothread = IOTHREAD(obj);
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000239 PollParamInfo *info = opaque;
240 int64_t *field = (void *)iothread + info->offset;
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000241 int64_t value;
242
Markus Armbruster668f62e2020-07-07 18:06:02 +0200243 if (!visit_type_int64(v, name, &value, errp)) {
Markus Armbrusterdcfe4802020-07-07 18:06:01 +0200244 return;
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000245 }
246
247 if (value < 0) {
Markus Armbrusterdcfe4802020-07-07 18:06:01 +0200248 error_setg(errp, "%s value must be in range [0, %" PRId64 "]",
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000249 info->name, INT64_MAX);
Markus Armbrusterdcfe4802020-07-07 18:06:01 +0200250 return;
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000251 }
252
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000253 *field = value;
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000254
255 if (iothread->ctx) {
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000256 aio_context_set_poll_params(iothread->ctx,
257 iothread->poll_max_ns,
258 iothread->poll_grow,
259 iothread->poll_shrink,
Markus Armbrusterdcfe4802020-07-07 18:06:01 +0200260 errp);
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000261 }
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000262}
263
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100264static void iothread_class_init(ObjectClass *klass, void *class_data)
265{
266 UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
267 ucc->complete = iothread_complete;
Stefan Hajnoczi0d9d86f2016-12-01 19:26:45 +0000268
269 object_class_property_add(klass, "poll-max-ns", "int",
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000270 iothread_get_poll_param,
271 iothread_set_poll_param,
Markus Armbrusterd2623122020-05-05 17:29:22 +0200272 NULL, &poll_max_ns_info);
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000273 object_class_property_add(klass, "poll-grow", "int",
274 iothread_get_poll_param,
275 iothread_set_poll_param,
Markus Armbrusterd2623122020-05-05 17:29:22 +0200276 NULL, &poll_grow_info);
Stefan Hajnoczi5e5db492016-12-01 19:26:52 +0000277 object_class_property_add(klass, "poll-shrink", "int",
278 iothread_get_poll_param,
279 iothread_set_poll_param,
Markus Armbrusterd2623122020-05-05 17:29:22 +0200280 NULL, &poll_shrink_info);
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100281}
282
283static const TypeInfo iothread_info = {
284 .name = TYPE_IOTHREAD,
285 .parent = TYPE_OBJECT,
286 .class_init = iothread_class_init,
287 .instance_size = sizeof(IOThread),
Stefan Hajnoczicdd7abf2017-01-26 17:01:19 +0000288 .instance_init = iothread_instance_init,
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100289 .instance_finalize = iothread_instance_finalize,
290 .interfaces = (InterfaceInfo[]) {
291 {TYPE_USER_CREATABLE},
292 {}
293 },
294};
295
296static void iothread_register_types(void)
297{
298 type_register_static(&iothread_info);
299}
300
301type_init(iothread_register_types)
302
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100303char *iothread_get_id(IOThread *iothread)
304{
Markus Armbruster7a309cc2020-07-14 18:02:00 +0200305 return g_strdup(object_get_canonical_path_component(OBJECT(iothread)));
Stefan Hajnoczibe8d8532014-03-03 11:30:05 +0100306}
307
308AioContext *iothread_get_aio_context(IOThread *iothread)
309{
310 return iothread->ctx;
311}
Stefan Hajnoczidc3dd0d2014-02-27 11:48:42 +0100312
313static int query_one_iothread(Object *object, void *opaque)
314{
315 IOThreadInfoList ***prev = opaque;
316 IOThreadInfoList *elem;
317 IOThreadInfo *info;
318 IOThread *iothread;
319
320 iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
321 if (!iothread) {
322 return 0;
323 }
324
325 info = g_new0(IOThreadInfo, 1);
326 info->id = iothread_get_id(iothread);
327 info->thread_id = iothread->thread_id;
Pavel Hrdina5fc00482017-02-10 10:41:17 +0100328 info->poll_max_ns = iothread->poll_max_ns;
329 info->poll_grow = iothread->poll_grow;
330 info->poll_shrink = iothread->poll_shrink;
Stefan Hajnoczidc3dd0d2014-02-27 11:48:42 +0100331
332 elem = g_new0(IOThreadInfoList, 1);
333 elem->value = info;
334 elem->next = NULL;
335
336 **prev = elem;
337 *prev = &elem->next;
338 return 0;
339}
340
341IOThreadInfoList *qmp_query_iothreads(Error **errp)
342{
343 IOThreadInfoList *head = NULL;
344 IOThreadInfoList **prev = &head;
Daniel P. Berrangebc2256c2015-05-13 17:14:05 +0100345 Object *container = object_get_objects_root();
Stefan Hajnoczidc3dd0d2014-02-27 11:48:42 +0100346
347 object_child_foreach(container, query_one_iothread, &prev);
348 return head;
349}
Fam Zhengdce89212016-09-08 17:28:51 +0800350
Wang Yong329163c2017-08-29 15:22:37 +0800351GMainContext *iothread_get_g_main_context(IOThread *iothread)
352{
Peter Xub506e0f2019-03-06 19:55:29 +0800353 atomic_set(&iothread->run_gcontext, 1);
354 aio_notify(iothread->ctx);
Wang Yong329163c2017-08-29 15:22:37 +0800355 return iothread->worker_context;
356}
Peter Xu0173e212017-09-28 10:59:55 +0800357
358IOThread *iothread_create(const char *id, Error **errp)
359{
360 Object *obj;
361
362 obj = object_new_with_props(TYPE_IOTHREAD,
363 object_get_internal_root(),
364 id, errp, NULL);
365
366 return IOTHREAD(obj);
367}
368
369void iothread_destroy(IOThread *iothread)
370{
371 object_unparent(OBJECT(iothread));
372}
Stefan Hajnoczifbcc6922017-12-06 14:45:48 +0000373
374/* Lookup IOThread by its id. Only finds user-created objects, not internal
375 * iothread_create() objects. */
376IOThread *iothread_by_id(const char *id)
377{
378 return IOTHREAD(object_resolve_path_type(id, TYPE_IOTHREAD, NULL));
379}