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 "qom/object.h" 15 #include "qom/object_interfaces.h" 16 #include "qemu/module.h" 17 #include "block/aio.h" 18 #include "sysemu/iothread.h" 19 #include "qmp-commands.h" 20 #include "qemu/error-report.h" 21 #include "qemu/rcu.h" 22 23 typedef ObjectClass IOThreadClass; 24 25 #define IOTHREAD_GET_CLASS(obj) \ 26 OBJECT_GET_CLASS(IOThreadClass, obj, TYPE_IOTHREAD) 27 #define IOTHREAD_CLASS(klass) \ 28 OBJECT_CLASS_CHECK(IOThreadClass, klass, TYPE_IOTHREAD) 29 30 static void *iothread_run(void *opaque) 31 { 32 IOThread *iothread = opaque; 33 bool blocking; 34 35 rcu_register_thread(); 36 37 qemu_mutex_lock(&iothread->init_done_lock); 38 iothread->thread_id = qemu_get_thread_id(); 39 qemu_cond_signal(&iothread->init_done_cond); 40 qemu_mutex_unlock(&iothread->init_done_lock); 41 42 while (!iothread->stopping) { 43 aio_context_acquire(iothread->ctx); 44 blocking = true; 45 while (!iothread->stopping && aio_poll(iothread->ctx, blocking)) { 46 /* Progress was made, keep going */ 47 blocking = false; 48 } 49 aio_context_release(iothread->ctx); 50 } 51 52 rcu_unregister_thread(); 53 return NULL; 54 } 55 56 static void iothread_instance_finalize(Object *obj) 57 { 58 IOThread *iothread = IOTHREAD(obj); 59 60 if (!iothread->ctx) { 61 return; 62 } 63 iothread->stopping = true; 64 aio_notify(iothread->ctx); 65 qemu_thread_join(&iothread->thread); 66 qemu_cond_destroy(&iothread->init_done_cond); 67 qemu_mutex_destroy(&iothread->init_done_lock); 68 aio_context_unref(iothread->ctx); 69 } 70 71 static void iothread_complete(UserCreatable *obj, Error **errp) 72 { 73 Error *local_error = NULL; 74 IOThread *iothread = IOTHREAD(obj); 75 char *name, *thread_name; 76 77 iothread->stopping = false; 78 iothread->thread_id = -1; 79 iothread->ctx = aio_context_new(&local_error); 80 if (!iothread->ctx) { 81 error_propagate(errp, local_error); 82 return; 83 } 84 85 qemu_mutex_init(&iothread->init_done_lock); 86 qemu_cond_init(&iothread->init_done_cond); 87 88 /* This assumes we are called from a thread with useful CPU affinity for us 89 * to inherit. 90 */ 91 name = object_get_canonical_path_component(OBJECT(obj)); 92 thread_name = g_strdup_printf("IO %s", name); 93 qemu_thread_create(&iothread->thread, thread_name, iothread_run, 94 iothread, QEMU_THREAD_JOINABLE); 95 g_free(thread_name); 96 g_free(name); 97 98 /* Wait for initialization to complete */ 99 qemu_mutex_lock(&iothread->init_done_lock); 100 while (iothread->thread_id == -1) { 101 qemu_cond_wait(&iothread->init_done_cond, 102 &iothread->init_done_lock); 103 } 104 qemu_mutex_unlock(&iothread->init_done_lock); 105 } 106 107 static void iothread_class_init(ObjectClass *klass, void *class_data) 108 { 109 UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass); 110 ucc->complete = iothread_complete; 111 } 112 113 static const TypeInfo iothread_info = { 114 .name = TYPE_IOTHREAD, 115 .parent = TYPE_OBJECT, 116 .class_init = iothread_class_init, 117 .instance_size = sizeof(IOThread), 118 .instance_finalize = iothread_instance_finalize, 119 .interfaces = (InterfaceInfo[]) { 120 {TYPE_USER_CREATABLE}, 121 {} 122 }, 123 }; 124 125 static void iothread_register_types(void) 126 { 127 type_register_static(&iothread_info); 128 } 129 130 type_init(iothread_register_types) 131 132 char *iothread_get_id(IOThread *iothread) 133 { 134 return object_get_canonical_path_component(OBJECT(iothread)); 135 } 136 137 AioContext *iothread_get_aio_context(IOThread *iothread) 138 { 139 return iothread->ctx; 140 } 141 142 static int query_one_iothread(Object *object, void *opaque) 143 { 144 IOThreadInfoList ***prev = opaque; 145 IOThreadInfoList *elem; 146 IOThreadInfo *info; 147 IOThread *iothread; 148 149 iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD); 150 if (!iothread) { 151 return 0; 152 } 153 154 info = g_new0(IOThreadInfo, 1); 155 info->id = iothread_get_id(iothread); 156 info->thread_id = iothread->thread_id; 157 158 elem = g_new0(IOThreadInfoList, 1); 159 elem->value = info; 160 elem->next = NULL; 161 162 **prev = elem; 163 *prev = &elem->next; 164 return 0; 165 } 166 167 IOThreadInfoList *qmp_query_iothreads(Error **errp) 168 { 169 IOThreadInfoList *head = NULL; 170 IOThreadInfoList **prev = &head; 171 Object *container = object_get_objects_root(); 172 173 object_child_foreach(container, query_one_iothread, &prev); 174 return head; 175 } 176