alloc_irq_cpu_rmap(9)

✨ alloc_irq_cpu_rmap 💅

okay so this is from the Kernel API Manual (that's the 9 section bestie, kernel dev territory 👑) and it's literally the page for alloc_irq_cpu_rmap — the function that allocates a CPU affinity reverse-map for IRQs. yes that's a whole mouthful, we'll get to it 🫶

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🌸 NAME 🌸

alloc_irq_cpu_rmap — allocate CPU affinity reverse-map for IRQs ✨

no cap, that's the whole vibe: you're building the reverse-map so you can go from an IRQ back to the CPUs that are down with it 💖

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🎀 SYNOPSIS 🎀

struct cpu_rmap * alloc_irq_cpu_rmap (unsigned int size );

it hands you back a struct cpu_rmap * pointer, and you feed it one unsigned int size. that's the whole signature, iconic and simple 🌟

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🦋 ARGUMENTS 🦋

• size — Number of objects to be mapped. literally that many things getting mapped, so like, pick your number wisely bestie 💅

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🔥 DESCRIPTION 🔥

so here's the thing — Must be called in process context. periodt. not interrupt context, not some random atomic corner, process context only. the way this is a hard requirement and not a suggestion 😭 take it seriously fr fr 🙈

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💜 SEE ALSO 💜

• Kernel file ./include/linux/cpu_rmap.h — the header where all this lives, go read it, it's giving source of truth 🎀
• struct cpu_rmap(9) — the struct itself, the main character of this whole story 👑

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🍓 lowkey reminder: size = number of objects to be mapped, and process context is non-negotiable. that's it, that's the page 💀✨

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and that's a wrap bestie!! 🌈 this lil page comes to you from ./include/linux, dated October 2026 — mwah, go map those IRQs, you're gonna slay 💖🧚‍♀️⭐