irq_reserve_ipi(9)

💅 irq_reserve_ipi(9) — Kernel API Manual

okay so bestie, welcome to irq_reserve_ipi, the function in the Kernel API Manual (section 9, we're doing kernel internals today 🎀) that sets up an IPI to a destination cpumask. yes it's giving low-level, yes it's iconic, let's get into it ✨

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✨ NAME ✨

irq_reserve_ipi — Setup an IPI to destination cpumask 🦋

🌸 SYNOPSIS 🌸

int irq_reserve_ipi (struct irq_domain *domain , const struct cpumask
*dest );

💖 ARGUMENTS 💖

• domain — the IPI domain, bestie 🫶
• dest — the cpumask of CPUs which can receive the IPI. like, the whole guest list of who's allowed to get this interrupt 💌

👑 DESCRIPTION 👑

So what it does is: it allocates a virq that can be used to send an IPI to any CPU in the dest mask. that's it, that's the whole vibe. one virq, and it's valid for every CPU hanging out in that mask 💅✨

🔥 RETURN 🔥

On success you get the Linux IRQ number back. on failure? you get an error code. no cap, that's the deal 💀

ngl bestie, always check the return value — success gives you an IRQ number, failure gives you an error code, and those are NOT the same thing 🙈

🌈 SEE ALSO 🌈

Kernel file ./kernel/irq/ipi.c — go read it, it's right there 💜

• irq_destroy_ipi(9)
• ipi_get_hwirq(9)
• __ipi_send_single(9)
• __ipi_send_mask(9)
• ipi_send_single(9)
• ipi_send_mask(9)

all the IPI besties, together, the way it should be 🧚🍓

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and that's the page fr fr 🎀 it lives in ./kernel/irq and this version is dated October 2026, page irq_reserve_ipi(9) — mwah, slay, periodt 💅💖