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