基于linux2.6.12.1的进程睡眠原理是什么

unsigned int sleep(unsigned int seconds);

On Linux, sleep() is implemented via nanosleep(2).  See the nanosleep(2) man page for a discussion of the clock used.

asmlinkage long sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp){  struct timespec t;  unsigned long expire;  long ret;

  expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);  current->state = TASK_INTERRUPTIBLE;  expire = schedule_timeout(expire);

}

fastcall signed long __sched schedule_timeout(signed long timeout){  struct timer_list timer;  unsigned long expire;  // 算出超时时间  expire = timeout + jiffies;

  init_timer(&timer);  // 超时时间  timer.expires = expire;  timer.data = (unsigned long) current;  // 超时回调  timer.function = process_timeout;  // 添加定时器  add_timer(&timer);  // 进程调度  schedule();  // 删除定时器  del_singleshot_timer_sync(&timer);    // 超时或者被信号唤醒，被信号唤醒的话，可能还没有超时  timeout = expire - jiffies;

 out:  return timeout < 0 ? 0 : timeout;}

static void process_timeout(unsigned long __data){  wake_up_process((task_t *)__data);}

timer.data = (unsigned long) current;