spice之red worker工作流程浅析

redworker笔记

1）redworker由dispatcher（Red_dispatcher.c）以线程的形式启动
2）red_worker_main流程

SPICE_GNUC_NORETURN void *red_worker_main(void *arg)
{
    RedWorker *worker = spice_malloc(sizeof(RedWorker));

    spice_info("begin");
    spice_assert(MAX_PIPE_SIZE > WIDE_CLIENT_ACK_WINDOW &&
           MAX_PIPE_SIZE > NARROW_CLIENT_ACK_WINDOW); //ensure wakeup by ack message

#if defined(RED_WORKER_STAT) || defined(COMPRESS_STAT)
    if (pthread_getcpuclockid(pthread_self(), &clock_id)) {
        spice_error("pthread_getcpuclockid failed");
    }
#endif

//初始化worker,设置回调，内存池初始化，cache初始化等
    red_init(worker, (WorkerInitData *)arg);
//初始化解压器
    red_init_quic(worker);
    red_init_lz(worker);
    red_init_jpeg(worker);
    red_init_zlib(worker);
    worker->event_timeout = INF_EVENT_WAIT;
//进入循环，POLL处理事件
    for (;;) {
        int i, num_events;

        worker->event_timeout = MIN(red_get_streams_timout(worker), worker->event_timeout);
        num_events = poll(worker->poll_fds, MAX_EVENT_SOURCES, worker->event_timeout);
        red_handle_streams_timout(worker);

        if (worker->display_channel) {
            /* during migration, in the dest, the display channel can be initialized
               while the global lz data not since migrate data msg hasn't been
               received yet */
            red_channel_apply_clients(&worker->display_channel->common.base,
                                      red_display_cc_free_glz_drawables);
        }

        worker->event_timeout = INF_EVENT_WAIT;
        if (num_events == -1) {
            if (errno != EINTR) {
                spice_error("poll failed, %s", strerror(errno));
            }
        }

        for (i = 0; i < MAX_EVENT_SOURCES; i++) {
            /* The watch may have been removed by the watch-func from
               another fd (ie a disconnect through the dispatcher),
               in this case watch_func is NULL. */
            if (worker->poll_fds[i].revents && worker->watches[i].watch_func) {
                int events = 0;
                if (worker->poll_fds[i].revents & POLLIN) {
                    events |= SPICE_WATCH_EVENT_READ;
                }
                if (worker->poll_fds[i].revents & POLLOUT) {
                    events |= SPICE_WATCH_EVENT_WRITE;
                }
//dispatcher 交互
                worker->watches[i].watch_func(worker->poll_fds[i].fd, events,
                                        worker->watches[i].watch_func_opaque);
            }
        }

        /* Clear the poll_fd for any removed watches, see the comment in
           watch_remove for why we don't do this there. */
        for (i = 0; i < MAX_EVENT_SOURCES; i++) {
            if (!worker->watches[i].watch_func) {
                worker->poll_fds[i].fd = -1;
            }
        }

//QXL Device 交互
        if (worker->running) {
            int ring_is_empty;
            red_process_cursor(worker, MAX_PIPE_SIZE, &ring_is_empty);
            red_process_commands(worker, MAX_PIPE_SIZE, &ring_is_empty);
        }
        red_push(worker);
    }
    abort();
}

参考：spice_for_newbies.pdf