__ipi_send_mask(9)

💅 __ipi_send_mask — send an IPI to target Linux SMP CPU(s)

okay so bestie, we're in the Kernel API Manual today, and the star of the show is __ipi_send_mask from __ipi_send_mask(9). yes it has the double underscore, no you cannot skip it, she's built different 🎀

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✨ SYNOPSIS ✨

int __ipi_send_mask (struct irq_desc *desc , const struct cpumask *dest
);

like literally that's the whole signature. one int, two args, zero drama 💅

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🫶 ARGUMENTS 🫶

• desc — pointer to the irq_desc of the IRQ. that's her little info card, she needs it, don't lose it 🙈
• dest — the destination CPU(s), and this one comes with a vibe check: it must be a subset of the mask passed to irq_reserve_ipi. not a superset, not a "close enough", a subset. periodt 💀

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🌸 DESCRIPTION 🌸

okay so here's the tea — this function exists for architecture or core code to speed up IPI sending. she's the fast lane, the express checkout, the "don't talk to me I'm busy" of IPI delivery ⚡

and the big one, listen carefully:

NOT usable from driver code. like. at all. this is not for you, driver bestie, this is core-code-only, iykyk 😭

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⭐ RETURN ⭐

• 0 on success 🎉 (slay, everything worked)
• a negative error number on failure 😔 (it's giving "something went wrong", read the number and cope)

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🦋 SEE ALSO 🦋

the whole friend group lives in the kernel file ./kernel/irq/ipi.c, go say hi to:

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

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and that's the page, bestie 🌈 this lil cutie lives in ./kernel/irq, dated October 2026, and she goes by __ipi_send_mask(9) — go forth and send those IPIs responsibly, mwah 💖🎀