tests/iothread.c

   1 /*
   2  * Event loop thread implementation for unit tests
   3  *
   4  * Copyright Red Hat Inc., 2013, 2016
   5  *
   6  * Authors:
   7  *  Stefan Hajnoczi   <stefanha@redhat.com>
   8  *  Paolo Bonzini     <pbonzini@redhat.com>
   9  *
  10  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  11  * See the COPYING file in the top-level directory.
  12  *
  13  */
  14
  15 #include "qemu/osdep.h"
  16 #include "qapi/error.h"
  17 #include "block/aio.h"
  18 #include "qemu/main-loop.h"
  19 #include "qemu/rcu.h"
  20 #include "iothread.h"
  21
  22 struct IOThread {
  23     AioContext *ctx;
  24
  25     QemuThread thread;
  26     QemuMutex init_done_lock;
  27     QemuCond init_done_cond;    /* is thread initialization done? */
  28     bool stopping;
  29 };
  30
  31 static __thread IOThread *my_iothread;
  32
  33 AioContext *qemu_get_current_aio_context(void)
  34 {
  35     return my_iothread ? my_iothread->ctx : qemu_get_aio_context();
  36 }
  37
  38 static void *iothread_run(void *opaque)
  39 {
  40     IOThread *iothread = opaque;
  41
  42     rcu_register_thread();
  43
  44     my_iothread = iothread;
  45     qemu_mutex_lock(&iothread->init_done_lock);
  46     iothread->ctx = aio_context_new(&error_abort);
  47     qemu_cond_signal(&iothread->init_done_cond);
  48     qemu_mutex_unlock(&iothread->init_done_lock);
  49
  50     while (!atomic_read(&iothread->stopping)) {
  51         aio_poll(iothread->ctx, true);
  52     }
  53
  54     rcu_unregister_thread();
  55     return NULL;
  56 }
  57
  58 static void iothread_stop_bh(void *opaque)
  59 {
  60     IOThread *iothread = opaque;
  61
  62     iothread->stopping = true;
  63 }
  64
  65 void iothread_join(IOThread *iothread)
  66 {
  67     aio_bh_schedule_oneshot(iothread->ctx, iothread_stop_bh, iothread);
  68     qemu_thread_join(&iothread->thread);
  69     qemu_cond_destroy(&iothread->init_done_cond);
  70     qemu_mutex_destroy(&iothread->init_done_lock);
  71     aio_context_unref(iothread->ctx);
  72     g_free(iothread);
  73 }
  74
  75 IOThread *iothread_new(void)
  76 {
  77     IOThread *iothread = g_new0(IOThread, 1);
  78
  79     qemu_mutex_init(&iothread->init_done_lock);
  80     qemu_cond_init(&iothread->init_done_cond);
  81     qemu_thread_create(&iothread->thread, NULL, iothread_run,
  82                        iothread, QEMU_THREAD_JOINABLE);
  83
  84     /* Wait for initialization to complete */
  85     qemu_mutex_lock(&iothread->init_done_lock);
  86     while (iothread->ctx == NULL) {
  87         qemu_cond_wait(&iothread->init_done_cond,
  88                        &iothread->init_done_lock);
  89     }
  90     qemu_mutex_unlock(&iothread->init_done_lock);
  91     return iothread;
  92 }
  93
  94 AioContext *iothread_get_aio_context(IOThread *iothread)
  95 {
  96     return iothread->ctx;
  97 }