@@ -3063,6 +3063,12 @@ static int postcopy_start(MigrationState *ms)
int64_t bandwidth = migrate_max_postcopy_bandwidth();
bool restart_block = false;
int cur_state = MIGRATION_STATUS_ACTIVE;
+
+ if (postcopy_preempt_wait_channel(ms)) {
+ migrate_set_state(&ms->state, ms->state, MIGRATION_STATUS_FAILED);
+ return -1;
+ }
+
if (!migrate_pause_before_switchover()) {
migrate_set_state(&ms->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_POSTCOPY_ACTIVE);
@@ -3544,6 +3550,14 @@ static MigThrError postcopy_pause(MigrationState *s)
if (s->state == MIGRATION_STATUS_POSTCOPY_RECOVER) {
/* Woken up by a recover procedure. Give it a shot */
+ if (postcopy_preempt_wait_channel(s)) {
+ /*
+ * Preempt enabled, and new channel create failed; loop
+ * back to wait for another recovery.
+ */
+ continue;
+ }
+
/*
* Firstly, let's wake up the return path now, with a new
* return path channel.
@@ -4407,6 +4421,7 @@ static void migration_instance_finalize(Object *obj)
qemu_sem_destroy(&ms->postcopy_pause_sem);
qemu_sem_destroy(&ms->postcopy_pause_rp_sem);
qemu_sem_destroy(&ms->rp_state.rp_sem);
+ qemu_sem_destroy(&ms->postcopy_qemufile_src_sem);
error_free(ms->error);
}
@@ -4456,6 +4471,7 @@ static void migration_instance_init(Object *obj)
qemu_sem_init(&ms->rp_state.rp_sem, 0);
qemu_sem_init(&ms->rate_limit_sem, 0);
qemu_sem_init(&ms->wait_unplug_sem, 0);
+ qemu_sem_init(&ms->postcopy_qemufile_src_sem, 0);
qemu_mutex_init(&ms->qemu_file_lock);
}
@@ -219,6 +219,13 @@ struct MigrationState {
QEMUFile *to_dst_file;
/* Postcopy specific transfer channel */
QEMUFile *postcopy_qemufile_src;
+ /*
+ * It is posted when the preempt channel is established. Note: this is
+ * used for both the start or recover of a postcopy migration. We'll
+ * post to this sem every time a new preempt channel is created in the
+ * main thread, and we keep post() and wait() in pair.
+ */
+ QemuSemaphore postcopy_qemufile_src_sem;
QIOChannelBuffer *bioc;
/*
* Protects to_dst_file/from_dst_file pointers. We need to make sure we
@@ -1552,10 +1552,50 @@ bool postcopy_preempt_new_channel(MigrationIncomingState *mis, QEMUFile *file)
return true;
}
-int postcopy_preempt_setup(MigrationState *s, Error **errp)
+static void
+postcopy_preempt_send_channel_new(QIOTask *task, gpointer opaque)
{
- QIOChannel *ioc;
+ MigrationState *s = opaque;
+ QIOChannel *ioc = QIO_CHANNEL(qio_task_get_source(task));
+ Error *local_err = NULL;
+
+ if (qio_task_propagate_error(task, &local_err)) {
+ /* Something wrong happened.. */
+ migrate_set_error(s, local_err);
+ error_free(local_err);
+ } else {
+ migration_ioc_register_yank(ioc);
+ s->postcopy_qemufile_src = qemu_fopen_channel_output(ioc);
+ trace_postcopy_preempt_new_channel();
+ }
+
+ /*
+ * Kick the waiter in all cases. The waiter should check upon
+ * postcopy_qemufile_src to know whether it failed or not.
+ */
+ qemu_sem_post(&s->postcopy_qemufile_src_sem);
+ object_unref(OBJECT(ioc));
+}
+/* Returns 0 if channel established, -1 for error. */
+int postcopy_preempt_wait_channel(MigrationState *s)
+{
+ /* If preempt not enabled, no need to wait */
+ if (!migrate_postcopy_preempt()) {
+ return 0;
+ }
+
+ /*
+ * We need the postcopy preempt channel to be established before
+ * starting doing anything.
+ */
+ qemu_sem_wait(&s->postcopy_qemufile_src_sem);
+
+ return s->postcopy_qemufile_src ? 0 : -1;
+}
+
+int postcopy_preempt_setup(MigrationState *s, Error **errp)
+{
if (!migrate_postcopy_preempt()) {
return 0;
}
@@ -1566,16 +1606,8 @@ int postcopy_preempt_setup(MigrationState *s, Error **errp)
return -1;
}
- ioc = socket_send_channel_create_sync(errp);
-
- if (ioc == NULL) {
- return -1;
- }
-
- migration_ioc_register_yank(ioc);
- s->postcopy_qemufile_src = qemu_fopen_channel_output(ioc);
-
- trace_postcopy_preempt_new_channel();
+ /* Kick an async task to connect */
+ socket_send_channel_create(postcopy_preempt_send_channel_new, s);
return 0;
}
@@ -192,5 +192,6 @@ enum PostcopyChannels {
bool postcopy_preempt_new_channel(MigrationIncomingState *mis, QEMUFile *file);
int postcopy_preempt_setup(MigrationState *s, Error **errp);
+int postcopy_preempt_wait_channel(MigrationState *s);
#endif