STRUCT IRQACTION(9)

💖 struct irqaction(9) 💖

ok so this is the Kernel API Manual page for struct irqaction and bestie, it's literally the per-interrupt action descriptor, no cap. like every single thing you ever wanted to know about one interrupt action lives in this one struct. let's get into it ✨

🌸 SYNOPSIS 🌸

here's the whole vibe, copied exactly because i would NEVER mess with your code:

struct irqaction {
    irq_handler_t handler;
    union {
      void *dev_id;
      void __percpu   *percpu_dev_id;
    };
    const struct cpumask    *affinity;
    struct irqaction        *next;
    irq_handler_t thread_fn;
    struct task_struct      *thread;
    struct irqaction        *secondary;
    unsigned int            irq;
    unsigned int            flags;
    unsigned long           thread_flags;
    unsigned long           thread_mask;
    const char              *name;
    struct proc_dir_entry   *dir;
 };

🎀 Members 🎀

okay so here's the member-by-member breakdown, and yes i'm gonna hype each one up because they all matter 💅

• handler — the interrupt handler function. this is the main character, the one who actually does the thing 🔥
• {unnamed_union} — it's anonymous. no name. mysterious. iconic. it's giving mystery box energy 🎁
• dev_id — cookie to identify the device 🍪 (fr fr, the manpage calls it a cookie)
• percpu_dev_id — cookie to identify the device, but per-CPU this time 🍪✨
• affinity — CPUs this irqaction is allowed to run on. it's the VIP list, and the guest list is CPUs 🌈
• next — pointer to the next irqaction for shared interrupts. chain of besties 🫶
• thread_fn — interrupt handler function for threaded interrupts, the threaded sibling of handler 🧵
• thread — thread pointer for threaded interrupts. it points at the thread, that's the whole job 😭
• secondary — pointer to secondary irqaction (force threading). dramatic name, real purpose 💀
• irq — interrupt number 🔢
• flags — flags (see IRQF_* above). go look up top, i'm not making stuff up 👀
• thread_flags — flags related to thread 🏳️
• thread_mask — bitmask for keeping track of thread activity. lowkey the accountant of the struct 📊
• name — name of the device. everyone needs a name bestie 💖
• dir — pointer to the proc/irq/NN/name entry. yes, that exact path, don't @ me 📁

👑 SEE ALSO 👑

• Kernel file ./include/linux/interrupt.h
• request_irq(9)
• struct irq_affinity_notify(9)
• struct irq_affinity(9)
• struct irq_affinity_desc(9)
• irq_update_affinity_hint(9)
• irq_set_affinity_and_hint(9)

like, read those next, they're in the same friend group i promise 🦋

⭐ little sign-off star: this page lives in ./include/linux, it's dated October 2026, and it's part of the Kernel API Manual. now go forth and slay your interrupts 💜🎀