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 qemu_mutex_init(&iothread->init_done_lock); 102 qemu_cond_init(&iothread->init_done_cond); 103 104 /* This assumes we are called from a thread with useful CPU affinity for us 105 * to inherit. 106 */ 107 name = object_get_canonical_path_component(OBJECT(obj)); 108 thread_name = g_strdup_printf("IO %s", name); 109 qemu_thread_create(&iothread->thread, thread_name, iothread_run, 110 iothread, QEMU_THREAD_JOINABLE); 111 g_free(thread_name); 112 g_free(name); 113 114 /* Wait for initialization to complete */ 115 qemu_mutex_lock(&iothread->init_done_lock); 116 while (iothread->thread_id == -1) { 117 qemu_cond_wait(&iothread->init_done_cond, 118 &iothread->init_done_lock); 119 } 120 qemu_mutex_unlock(&iothread->init_done_lock); 121 } 122 123 static void iothread_class_init(ObjectClass *klass, void *class_data) 124 { 125 UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass); 126 ucc->complete = iothread_complete; 127 } 128 129 static const TypeInfo iothread_info = { 130 .name = TYPE_IOTHREAD, 131 .parent = TYPE_OBJECT, 132 .class_init = iothread_class_init, 133 .instance_size = sizeof(IOThread), 134 .instance_finalize = iothread_instance_finalize, 135 .interfaces = (InterfaceInfo[]) { 136 {TYPE_USER_CREATABLE}, 137 {} 138 }, 139 }; 140 141 static void iothread_register_types(void) 142 { 143 type_register_static(&iothread_info); 144 } 145 146 type_init(iothread_register_types) 147 148 char *iothread_get_id(IOThread *iothread) 149 { 150 return object_get_canonical_path_component(OBJECT(iothread)); 151 } 152 153 AioContext *iothread_get_aio_context(IOThread *iothread) 154 { 155 return iothread->ctx; 156 } 157 158 static int query_one_iothread(Object *object, void *opaque) 159 { 160 IOThreadInfoList ***prev = opaque; 161 IOThreadInfoList *elem; 162 IOThreadInfo *info; 163 IOThread *iothread; 164 165 iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD); 166 if (!iothread) { 167 return 0; 168 } 169 170 info = g_new0(IOThreadInfo, 1); 171 info->id = iothread_get_id(iothread); 172 info->thread_id = iothread->thread_id; 173 174 elem = g_new0(IOThreadInfoList, 1); 175 elem->value = info; 176 elem->next = NULL; 177 178 **prev = elem; 179 *prev = &elem->next; 180 return 0; 181 } 182 183 IOThreadInfoList *qmp_query_iothreads(Error **errp) 184 { 185 IOThreadInfoList *head = NULL; 186 IOThreadInfoList **prev = &head; 187 Object *container = object_get_objects_root(); 188 189 object_child_foreach(container, query_one_iothread, &prev); 190 return head; 191 } 192 193 void iothread_stop_all(void) 194 { 195 Object *container = object_get_objects_root(); 196 BlockDriverState *bs; 197 BdrvNextIterator it; 198 199 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 200 AioContext *ctx = bdrv_get_aio_context(bs); 201 if (ctx == qemu_get_aio_context()) { 202 continue; 203 } 204 aio_context_acquire(ctx); 205 bdrv_set_aio_context(bs, qemu_get_aio_context()); 206 aio_context_release(ctx); 207 } 208 209 object_child_foreach(container, iothread_stop, NULL); 210 } 211