LXR qemu/iothread.c

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