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Oct 20, 2016 · Fundamentals

Understanding Linux Hard IRQ vs Soft IRQ: A Deep Dive into Kernel Interrupt Handling

This article explains the distinction between hard IRQ and soft IRQ in the Linux x86 32‑bit kernel, detailing how preempt_count tracks interrupt context, how do_IRQ, irq_enter, and irq_exit manage the transition, and how __do_softirq processes pending softirqs with code examples and diagrams.