为什么中断处理程序(ISR)无法入睡? [英] Why interrupt handlers (ISRs) cannot sleep?

问题描述

我很困惑为什么中断处理程序无法入睡?对于相同的问题，我有2个意见:-

I am very confuse to get why interrupt handler can't sleep? i got 2 views for the same issue:-

1. 中断处理程序不是可调度的吗?因为它没有task_struct.

1. Interrupt Handler is not schedulable? Because it has no task_struct.

如果处理程序处于睡眠状态，则系统可能会挂起，因为系统时钟中断被屏蔽并且无法安排睡眠过程.

if the handler sleeps, then the system may hang because the system clock interrupt is masked and incapable of scheduling the sleeping process.

中断处理程序是否可调度，
但是较低优先级的系统时钟中断
被这些优先级较高的中断所掩盖，
他们无法安排时间?

Are interrupt handlers schedule-able,
but while the lower priority system clock interrupt
is masked by these higher priority interrupts,
they cannot be scheduled?

请给我一个很好的例子.

Please give me a good example for the same.

推荐答案

您无法在Linux的中断处理程序中入睡，因为它们没有执行线程的支持.换句话说，它们不是可调度的实体.

You can't sleep in interrupt handlers in Linux because they are not backed by a thread of execution. In other words, they aren't schedulable entities.

大多数系统将中断处理分为两半，通常称为上半部分和下半部分.上半部分运行非常快，中断发生时(实际上以运行方式)中断发生时正在执行的一切—上半部分本身没有线程.因此，上半部分无法入睡，因为没有什么事情可以安排在睡眠结束后重新安排.

Most systems break interrupt processing into two halves, commonly called a top half and a bottom half. The top half runs very quickly, interrupting (and in fact running as) whatever was executing when the interrupt occurred-the top half has no thread itself. Consequently, the top half is unable to sleep, as there isn't anything to schedule back into when the sleep completes.

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