static void *migration_thread(void *opaque) { MigrationState *s = opaque; /* Used by the bandwidth calcs, updated later */ int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST); int64_t initial_bytes = 0; int64_t max_size = 0; int64_t start_time = initial_time; int64_t end_time; bool old_vm_running = false; bool entered_postcopy = false; /* The active state we expect to be in; ACTIVE or POSTCOPY_ACTIVE */ enum MigrationStatus current_active_state = MIGRATION_STATUS_ACTIVE; rcu_register_thread(); qemu_savevm_state_header(s->to_dst_file); if (migrate_postcopy_ram()) { /* Now tell the dest that it should open its end so it can reply */ qemu_savevm_send_open_return_path(s->to_dst_file); /* And do a ping that will make stuff easier to debug */ qemu_savevm_send_ping(s->to_dst_file, 1); /* * Tell the destination that we *might* want to do postcopy later; * if the other end can't do postcopy it should fail now, nice and * early. */ qemu_savevm_send_postcopy_advise(s->to_dst_file); } qemu_savevm_state_begin(s->to_dst_file, &s->params); s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start; current_active_state = MIGRATION_STATUS_ACTIVE; migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, MIGRATION_STATUS_ACTIVE); trace_migration_thread_setup_complete(); while (s->state == MIGRATION_STATUS_ACTIVE || s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { int64_t current_time; uint64_t pending_size; if (!qemu_file_rate_limit(s->to_dst_file)) { uint64_t pend_post, pend_nonpost; qemu_savevm_state_pending(s->to_dst_file, max_size, &pend_nonpost, &pend_post); pending_size = pend_nonpost + pend_post; trace_migrate_pending(pending_size, max_size, pend_post, pend_nonpost); if (pending_size && pending_size >= max_size) { /* Still a significant amount to transfer */ if (migrate_postcopy_ram() && s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE && pend_nonpost <= max_size && atomic_read(&s->start_postcopy)) { if (!postcopy_start(s, &old_vm_running)) { current_active_state = MIGRATION_STATUS_POSTCOPY_ACTIVE; entered_postcopy = true; } continue; } /* Just another iteration step */ qemu_savevm_state_iterate(s->to_dst_file, entered_postcopy); } else { trace_migration_thread_low_pending(pending_size); migration_completion(s, current_active_state, &old_vm_running, &start_time); break; } } if (qemu_file_get_error(s->to_dst_file)) { migrate_set_state(&s->state, current_active_state, MIGRATION_STATUS_FAILED); trace_migration_thread_file_err(); break; } current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); if (current_time >= initial_time + BUFFER_DELAY) { uint64_t transferred_bytes = qemu_ftell(s->to_dst_file) - initial_bytes; uint64_t time_spent = current_time - initial_time; double bandwidth = (double)transferred_bytes / time_spent; max_size = bandwidth * migrate_max_downtime() / 1000000; s->mbps = (((double) transferred_bytes * 8.0) / ((double) time_spent / 1000.0)) / 1000.0 / 1000.0; trace_migrate_transferred(transferred_bytes, time_spent, bandwidth, max_size); /* if we haven't sent anything, we don't want to recalculate 10000 is a small enough number for our purposes */ if (s->dirty_bytes_rate && transferred_bytes > 10000) { s->expected_downtime = s->dirty_bytes_rate / bandwidth; } qemu_file_reset_rate_limit(s->to_dst_file); initial_time = current_time; initial_bytes = qemu_ftell(s->to_dst_file); } if (qemu_file_rate_limit(s->to_dst_file)) { /* usleep expects microseconds */ g_usleep((initial_time + BUFFER_DELAY - current_time)*1000); } } trace_migration_thread_after_loop(); /* If we enabled cpu throttling for auto-converge, turn it off. */ cpu_throttle_stop(); end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); qemu_mutex_lock_iothread(); qemu_savevm_state_cleanup(); if (s->state == MIGRATION_STATUS_COMPLETED) { uint64_t transferred_bytes = qemu_ftell(s->to_dst_file); s->total_time = end_time - s->total_time; if (!entered_postcopy) { s->downtime = end_time - start_time; } if (s->total_time) { s->mbps = (((double) transferred_bytes * 8.0) / ((double) s->total_time)) / 1000; } runstate_set(RUN_STATE_POSTMIGRATE); } else { if (old_vm_running && !entered_postcopy) { vm_start(); } else { if (runstate_check(RUN_STATE_FINISH_MIGRATE)) { runstate_set(RUN_STATE_POSTMIGRATE); } } } qemu_bh_schedule(s->cleanup_bh); qemu_mutex_unlock_iothread(); rcu_unregister_thread(); return NULL; }