__ipi_send_single(9)

🌸 __ipi_send_single (9) — from the Kernel API Manual 💅

okay bestie, so this is a kernel API page, section 9, and the star of the show is __ipi_send_single — the little function that sends an IPI to a target Linux SMP CPU. that's it, that's the whole vibe. ✨

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🎀 NAME 🎀

__ipi_send_single — send an IPI to a target Linux SMP CPU

like, it literally does what it says on the tin, no cap. 🔥

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🦋 SYNOPSIS 🦋

int __ipi_send_single (struct irq_desc *desc , unsigned int cpu );

she's giving "small signature, big responsibility" energy fr fr 😭

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💖 ARGUMENTS 💖

• desc — pointer to the irq_desc of the IRQ. that's your irq descriptor bestie, hand her over 🫶
• cpu — the destination CPU. and listen, it must be in the destination mask that you passed to irq_reserve_ipi — no freelancing, no rogue CPUs, we don't do that here 💀

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🌈 DESCRIPTION 🌈

so the way this works is — this function is for architecture or core code to speed up IPI sending. it's the fast lane, the VIP entrance, the main character shortcut ⭐

🚨 but the big caveat: it is not usable from driver code. drivers, this is not for you, please step away from the velvet rope 🙈

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💜 RETURN 💜

• 0 on success — slay, we love a clean win 💅
• a negative error number on failure — not the vibe, but at least she tells you 😭

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🧚 SEE ALSO 🧚

kernel file ./kernel/irq/ipi.c plus the whole friend group:

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

iykyk 👑

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and that's the page babes 🍓 this one's living in ./kernel/irq, dated October 2026, and it's called __ipi_send_single(9) — goodbye, go send some IPIs responsibly, periodt 💖✨