这行代码定义了一个等待函数wait,使用woken_wake_function作为回调函数。当等待的条件满足时,woken_wake_function会被调用,唤醒等待的进程。 (2)等待是靠sk_wait_event函数实现,他的原理如下 至于上下文的计数器,是写等待计数。这个先忽略。 检查指定条件是否满足(这里是检查sk->sk_err和sk->sk_state)。 如果条件...
8. * the waitqueue @wq is woken up. 9. * 10. * wake_up() has to be called after changing any variable that could 11. * change the result of the wait condition. 12. */ 13. #define wait_event(wq, condition) \ 14. do 15. if 16. break; \ 17. __wait_event(wq, condition...
// file:net/core/sock.c int sk_wait_data(struct sock *sk, long *timeo, const struct sk_buff *skb) { DEFINE_WAIT_FUNC(wait, woken_wake_function); int rc; // 向sock等待队列添加等待项 add_wait_queue(sk_sleep(sk), &wait); sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); // 等待条件为...
1. 通过add_wait_queue()函数将一个进程添加到等待队列,首先获得自旋锁,然后调用__add_wait_queue()实现将新的等待进程添加等待队列(添加到等待队列的头部),然后解锁;代码如下: static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new) { list_add(&new->task_list, &head-...
void (*task_woken) (struct rq *this_rq, struct task_struct *task); void (*set_cpus_allowed)(struct task_struct *p, const struct cpumask *newmask); void (*rq_online)(struct rq *rq); void (*rq_offline)(struct rq *rq);
/** Preempt the current task with a newly woken task if needed:*/staticvoidcheck_preempt_wakeup(structrq *rq,structtask_struct *p,intwake_flags) { (1)//获取当前处理器运行队列正在运行的进程:rq->currstructtask_struct *curr = rq->curr; ...
幸运的是实时Linux具有一种可在时间上减弱实时与非实时操作的机制,这种机制表现为一种称为实时FIFO的驱动程序。当insmod将rtl_fifo.o驱动程序插入Linux内核时,该驱动程序将自己注册为RTLinux的一部分,并成为Linux驱动程序。一旦插入Linux内核,用户空间进程和实时任务都可使用实时Linux FIFO。 在深入探讨实时FIFO的细节之...
pthread_wait_np(); // wait to be woken up.。. // process interrupt now in realtime kernel context 。.. } } // interrupt handler unsigned int irq_handler(unsigned int irq, struct pt_regs *regs) { pthread_wakeup_np(pp_thread); // wake up thread to do IRQ post-processing ...
In computer operating systems terminology, a sleeping process can either be interruptible (woken via signals) or uninterruptible (woken explicitly). An uninterruptible sleep state is a sleep state that cannot handle a signal (such as waiting for disk or network IO (input/output)). ...
* the waitqueue @wq is woken up. * * wake_up() has to be called after changing any variable that could * change the result of the wait condition. */#definewait_event(wq, condition) \ do { \ if (condition) \ break; \ __wait_event(wq, condition); \ ...