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 void iothread_instance_finalize(Object *obj) 58 { 59 IOThread *iothread = IOTHREAD(obj); 60 61 if (!iothread->ctx) { 62 return; 63 } 64 iothread->stopping = true; 65 aio_notify(iothread->ctx); 66 qemu_thread_join(&iothread->thread); 67 qemu_cond_destroy(&iothread->init_done_cond); 68 qemu_mutex_destroy(&iothread->init_done_lock); 69 aio_context_unref(iothread->ctx); 70 } 71 72 static void iothread_complete(UserCreatable *obj, Error **errp) 73 { 74 Error *local_error = NULL; 75 IOThread *iothread = IOTHREAD(obj); 76 char *name, *thread_name; 77 78 iothread->stopping = false; 79 iothread->thread_id = -1; 80 iothread->ctx = aio_context_new(&local_error); 81 if (!iothread->ctx) { 82 error_propagate(errp, local_error); 83 return; 84 } 85 86 qemu_mutex_init(&iothread->init_done_lock); 87 qemu_cond_init(&iothread->init_done_cond); 88 89 /* This assumes we are called from a thread with useful CPU affinity for us 90 * to inherit. 91 */ 92 name = object_get_canonical_path_component(OBJECT(obj)); 93 thread_name = g_strdup_printf("IO %s", name); 94 qemu_thread_create(&iothread->thread, thread_name, iothread_run, 95 iothread, QEMU_THREAD_JOINABLE); 96 g_free(thread_name); 97 g_free(name); 98 99 /* Wait for initialization to complete */ 100 qemu_mutex_lock(&iothread->init_done_lock); 101 while (iothread->thread_id == -1) { 102 qemu_cond_wait(&iothread->init_done_cond, 103 &iothread->init_done_lock); 104 } 105 qemu_mutex_unlock(&iothread->init_done_lock); 106 } 107 108 static void iothread_class_init(ObjectClass *klass, void *class_data) 109 { 110 UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass); 111 ucc->complete = iothread_complete; 112 } 113 114 static const TypeInfo iothread_info = { 115 .name = TYPE_IOTHREAD, 116 .parent = TYPE_OBJECT, 117 .class_init = iothread_class_init, 118 .instance_size = sizeof(IOThread), 119 .instance_finalize = iothread_instance_finalize, 120 .interfaces = (InterfaceInfo[]) { 121 {TYPE_USER_CREATABLE}, 122 {} 123 }, 124 }; 125 126 static void iothread_register_types(void) 127 { 128 type_register_static(&iothread_info); 129 } 130 131 type_init(iothread_register_types) 132 133 char *iothread_get_id(IOThread *iothread) 134 { 135 return object_get_canonical_path_component(OBJECT(iothread)); 136 } 137 138 AioContext *iothread_get_aio_context(IOThread *iothread) 139 { 140 return iothread->ctx; 141 } 142 143 static int query_one_iothread(Object *object, void *opaque) 144 { 145 IOThreadInfoList ***prev = opaque; 146 IOThreadInfoList *elem; 147 IOThreadInfo *info; 148 IOThread *iothread; 149 150 iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD); 151 if (!iothread) { 152 return 0; 153 } 154 155 info = g_new0(IOThreadInfo, 1); 156 info->id = iothread_get_id(iothread); 157 info->thread_id = iothread->thread_id; 158 159 elem = g_new0(IOThreadInfoList, 1); 160 elem->value = info; 161 elem->next = NULL; 162 163 **prev = elem; 164 *prev = &elem->next; 165 return 0; 166 } 167 168 IOThreadInfoList *qmp_query_iothreads(Error **errp) 169 { 170 IOThreadInfoList *head = NULL; 171 IOThreadInfoList **prev = &head; 172 Object *container = object_get_objects_root(); 173 174 object_child_foreach(container, query_one_iothread, &prev); 175 return head; 176 } 177