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 "sysemu/iothread.h" 20 #include "qmp-commands.h" 21 #include "qemu/error-report.h" 22 #include "qemu/rcu.h" 23 24 typedef ObjectClass IOThreadClass; 25 26 #define IOTHREAD_GET_CLASS(obj) \ 27 OBJECT_GET_CLASS(IOThreadClass, obj, TYPE_IOTHREAD) 28 #define IOTHREAD_CLASS(klass) \ 29 OBJECT_CLASS_CHECK(IOThreadClass, klass, TYPE_IOTHREAD) 30 31 static void *iothread_run(void *opaque) 32 { 33 IOThread *iothread = opaque; 34 bool blocking; 35 36 rcu_register_thread(); 37 38 qemu_mutex_lock(&iothread->init_done_lock); 39 iothread->thread_id = qemu_get_thread_id(); 40 qemu_cond_signal(&iothread->init_done_cond); 41 qemu_mutex_unlock(&iothread->init_done_lock); 42 43 while (!iothread->stopping) { 44 aio_context_acquire(iothread->ctx); 45 blocking = true; 46 while (!iothread->stopping && aio_poll(iothread->ctx, blocking)) { 47 /* Progress was made, keep going */ 48 blocking = false; 49 } 50 aio_context_release(iothread->ctx); 51 } 52 53 rcu_unregister_thread(); 54 return NULL; 55 } 56 57 static int iothread_stop(Object *object, void *opaque) 58 { 59 IOThread *iothread; 60 61 iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD); 62 if (!iothread || !iothread->ctx) { 63 return 0; 64 } 65 iothread->stopping = true; 66 aio_notify(iothread->ctx); 67 qemu_thread_join(&iothread->thread); 68 return 0; 69 } 70 71 static void iothread_instance_finalize(Object *obj) 72 { 73 IOThread *iothread = IOTHREAD(obj); 74 75 iothread_stop(obj, NULL); 76 qemu_cond_destroy(&iothread->init_done_cond); 77 qemu_mutex_destroy(&iothread->init_done_lock); 78 if (!iothread->ctx) { 79 return; 80 } 81 aio_context_unref(iothread->ctx); 82 } 83 84 static void iothread_complete(UserCreatable *obj, Error **errp) 85 { 86 Error *local_error = NULL; 87 IOThread *iothread = IOTHREAD(obj); 88 char *name, *thread_name; 89 90 iothread->stopping = false; 91 iothread->thread_id = -1; 92 iothread->ctx = aio_context_new(&local_error); 93 if (!iothread->ctx) { 94 error_propagate(errp, local_error); 95 return; 96 } 97 98 qemu_mutex_init(&iothread->init_done_lock); 99 qemu_cond_init(&iothread->init_done_cond); 100 101 /* This assumes we are called from a thread with useful CPU affinity for us 102 * to inherit. 103 */ 104 name = object_get_canonical_path_component(OBJECT(obj)); 105 thread_name = g_strdup_printf("IO %s", name); 106 qemu_thread_create(&iothread->thread, thread_name, iothread_run, 107 iothread, QEMU_THREAD_JOINABLE); 108 g_free(thread_name); 109 g_free(name); 110 111 /* Wait for initialization to complete */ 112 qemu_mutex_lock(&iothread->init_done_lock); 113 while (iothread->thread_id == -1) { 114 qemu_cond_wait(&iothread->init_done_cond, 115 &iothread->init_done_lock); 116 } 117 qemu_mutex_unlock(&iothread->init_done_lock); 118 } 119 120 static void iothread_class_init(ObjectClass *klass, void *class_data) 121 { 122 UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass); 123 ucc->complete = iothread_complete; 124 } 125 126 static const TypeInfo iothread_info = { 127 .name = TYPE_IOTHREAD, 128 .parent = TYPE_OBJECT, 129 .class_init = iothread_class_init, 130 .instance_size = sizeof(IOThread), 131 .instance_finalize = iothread_instance_finalize, 132 .interfaces = (InterfaceInfo[]) { 133 {TYPE_USER_CREATABLE}, 134 {} 135 }, 136 }; 137 138 static void iothread_register_types(void) 139 { 140 type_register_static(&iothread_info); 141 } 142 143 type_init(iothread_register_types) 144 145 char *iothread_get_id(IOThread *iothread) 146 { 147 return object_get_canonical_path_component(OBJECT(iothread)); 148 } 149 150 AioContext *iothread_get_aio_context(IOThread *iothread) 151 { 152 return iothread->ctx; 153 } 154 155 static int query_one_iothread(Object *object, void *opaque) 156 { 157 IOThreadInfoList ***prev = opaque; 158 IOThreadInfoList *elem; 159 IOThreadInfo *info; 160 IOThread *iothread; 161 162 iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD); 163 if (!iothread) { 164 return 0; 165 } 166 167 info = g_new0(IOThreadInfo, 1); 168 info->id = iothread_get_id(iothread); 169 info->thread_id = iothread->thread_id; 170 171 elem = g_new0(IOThreadInfoList, 1); 172 elem->value = info; 173 elem->next = NULL; 174 175 **prev = elem; 176 *prev = &elem->next; 177 return 0; 178 } 179 180 IOThreadInfoList *qmp_query_iothreads(Error **errp) 181 { 182 IOThreadInfoList *head = NULL; 183 IOThreadInfoList **prev = &head; 184 Object *container = object_get_objects_root(); 185 186 object_child_foreach(container, query_one_iothread, &prev); 187 return head; 188 } 189 190 void iothread_stop_all(void) 191 { 192 Object *container = object_get_objects_root(); 193 194 object_child_foreach(container, iothread_stop, NULL); 195 } 196