Liangxu Linux

Apr 7, 2025 · Fundamentals

Why Do Interrupts Have a Top Half and Bottom Half? Exploring Linux’s Split ISR Design

This article explains the concept of interrupt top‑half and bottom‑half processing, why splitting an ISR improves system efficiency, and introduces common Linux mechanisms such as soft interrupts, tasklets, workqueues, timers, and delayed work for handling deferred tasks.