工作队列实现

优点：最短时间调度
缺点：工作队列执行完后，需要重新创建.

添加工作对象

static int work_qqueue(FAR struct usr_wqueue_s *wqueue,
FAR struct work_s *work, worker_t worker,
FAR void *arg, systime_t delay)
-> dq_addlast((FAR dq_entry_t *)work, &wqueue->q);

工作队列执行进程

void work_process(FAR struct kwork_wqueue_s *wqueue, systime_t period, int wndx)
{

work = (FAR struct work_s *)wqueue->q.head;
while (work)

ctick   = clock_systimer();
elapsed = ctick - work->qtime;
if (elapsed >= work->delay)
{

//时间到了，就执行这个节点， 执行完后，立即删除这个节点，
		(void)dq_rem((struct dq_entry_s *)work, &wqueue->q);
		work  = (FAR struct work_s *)wqueue->q.head;
		worker(arg); //执行函数

 else /* elapsed < work->delay */
    {
//找到需要等待最短时间的那个节点。
      elapsed += (ctick - stick);
      if (elapsed > work->delay)
        {
          elapsed = work->delay;
        
      remaining = work->delay - elapsed;
      if (remaining < next)
        {
          next = remaining;
        }
      work = (FAR struct work_s *)work->dq.flink;

//工作队列的对象的时间小于hpwork队列时间，则使用任务调用的时间period: 100ms
elapsed = clock_systimer() - stick;
if (elapsed < period && next > 0)
{
remaining = period - elapsed;
next = MIN(next, remaining);
wqueue->worker[wndx].busy = false;
usleep(next * USEC_PER_TICK);
wqueue->worker[wndx].busy = true;
}