The end of tasklets

Controlling Deferred Execution in the Kernel

内核中的延迟执行控制

A common problem in kernel development is controlling when a specific task should be done. Kernel code often executes in contexts where some actions (sleeping, for example, or calling into filesystems) are not possible.

内核开发中的一个常见问题是如何控制特定任务的执行时机。内核代码经常在一些受限的上下文中执行，在这些情况下，某些操作（例如休眠或调用文件系统）是不可行的。

Other actions, while possible, may prevent the kernel from taking care of a more important task in a timely manner.

此外，即使某些操作可以执行，它们也可能会阻碍内核及时处理更重要的任务。

The kernel community has developed a number of deferred-execution mechanisms designed to ensure that every task is handled at the right time.

为了解决这一问题，内核社区开发了多种延迟执行机制，以确保每项任务都能在适当的时机执行。

One of those mechanisms, tasklets, has been eyed for removal for years; that removal might just happen in the near future.

其中之一——tasklet 机制，多年来一直被认为应该移除；这种移除可能在不久的将来成为现实。

Deferred Execution in Interrupt Handlers

中断处理程序中的延迟执行

One context where deferred execution is often needed is interrupt handlers.

延迟执行最常见的应用场景之一是中断处理程序。

An interrupt diverts a CPU from whatever it was doing at the time and must be handled as quickly as possible; sleeping in an interrupt handler is not even remotely an option.

中断会打断 CPU 当前正在执行的任务，因此必须尽快处理；在中断处理程序中休眠是绝对不允许的。

So interrupt handlers typically just make a note of what needs to be done, then arrange for the actual work to be done in a more forgiving context.

因此，中断处理程序通常只是记录需要执行的任务，并安排在一个更宽松的上下文中执行实际工作。

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