| 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 "qemu/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 | GMainContext *worker_context; |
| 25 | GMainLoop *main_loop; |
| 26 | |
| 27 | QemuThread thread; |
| 28 | QemuMutex init_done_lock; |
| 29 | QemuCond init_done_cond; /* is thread initialization done? */ |
| 30 | bool stopping; |
| 31 | }; |
| 32 | |
| 33 | static void iothread_init_gcontext(IOThread *iothread) |
| 34 | { |
| 35 | GSource *source; |
| 36 | |
| 37 | iothread->worker_context = g_main_context_new(); |
| 38 | source = aio_get_g_source(iothread_get_aio_context(iothread)); |
| 39 | g_source_attach(source, iothread->worker_context); |
| 40 | g_source_unref(source); |
| 41 | iothread->main_loop = g_main_loop_new(iothread->worker_context, TRUE); |
| 42 | } |
| 43 | |
| 44 | static void *iothread_run(void *opaque) |
| 45 | { |
| 46 | IOThread *iothread = opaque; |
| 47 | |
| 48 | rcu_register_thread(); |
| 49 | |
| 50 | qemu_mutex_lock(&iothread->init_done_lock); |
| 51 | iothread->ctx = aio_context_new(&error_abort); |
| 52 | qemu_set_current_aio_context(iothread->ctx); |
| 53 | |
| 54 | /* |
| 55 | * We must connect the ctx to a GMainContext, because in older versions |
| 56 | * of glib the g_source_ref()/unref() functions are not threadsafe |
| 57 | * on sources without a context. |
| 58 | */ |
| 59 | iothread_init_gcontext(iothread); |
| 60 | |
| 61 | /* |
| 62 | * g_main_context_push_thread_default() must be called before anything |
| 63 | * in this new thread uses glib. |
| 64 | */ |
| 65 | g_main_context_push_thread_default(iothread->worker_context); |
| 66 | |
| 67 | qemu_cond_signal(&iothread->init_done_cond); |
| 68 | qemu_mutex_unlock(&iothread->init_done_lock); |
| 69 | |
| 70 | while (!qatomic_read(&iothread->stopping)) { |
| 71 | aio_poll(iothread->ctx, true); |
| 72 | } |
| 73 | |
| 74 | g_main_context_pop_thread_default(iothread->worker_context); |
| 75 | rcu_unregister_thread(); |
| 76 | return NULL; |
| 77 | } |
| 78 | |
| 79 | static void iothread_stop_bh(void *opaque) |
| 80 | { |
| 81 | IOThread *iothread = opaque; |
| 82 | |
| 83 | iothread->stopping = true; |
| 84 | } |
| 85 | |
| 86 | void iothread_join(IOThread *iothread) |
| 87 | { |
| 88 | aio_bh_schedule_oneshot(iothread->ctx, iothread_stop_bh, iothread); |
| 89 | qemu_thread_join(&iothread->thread); |
| 90 | g_main_context_unref(iothread->worker_context); |
| 91 | g_main_loop_unref(iothread->main_loop); |
| 92 | qemu_cond_destroy(&iothread->init_done_cond); |
| 93 | qemu_mutex_destroy(&iothread->init_done_lock); |
| 94 | aio_context_unref(iothread->ctx); |
| 95 | g_free(iothread); |
| 96 | } |
| 97 | |
| 98 | IOThread *iothread_new(void) |
| 99 | { |
| 100 | IOThread *iothread = g_new0(IOThread, 1); |
| 101 | |
| 102 | qemu_mutex_init(&iothread->init_done_lock); |
| 103 | qemu_cond_init(&iothread->init_done_cond); |
| 104 | qemu_thread_create(&iothread->thread, NULL, iothread_run, |
| 105 | iothread, QEMU_THREAD_JOINABLE); |
| 106 | |
| 107 | /* Wait for initialization to complete */ |
| 108 | qemu_mutex_lock(&iothread->init_done_lock); |
| 109 | while (iothread->ctx == NULL) { |
| 110 | qemu_cond_wait(&iothread->init_done_cond, |
| 111 | &iothread->init_done_lock); |
| 112 | } |
| 113 | qemu_mutex_unlock(&iothread->init_done_lock); |
| 114 | return iothread; |
| 115 | } |
| 116 | |
| 117 | AioContext *iothread_get_aio_context(IOThread *iothread) |
| 118 | { |
| 119 | return iothread->ctx; |
| 120 | } |