__remove_pages(9)

💅 __remove_pages — Kernel API Manual, bestie edition

okay so picture this: you're deep in the kernel, you're doing memory hotplug things, and you need to yeet a whole chunk of pages out of existence (well, out of the mapping). That's this function. It's the manual's main character, and the manual name is literally "Kernel API Manual" — we love a title. 🎀

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✨ NAME ✨

__remove_pages — removes sections of pages, no cap 🫶

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🌸 SYNOPSIS 🌸

void __remove_pages (unsigned long pfn , unsigned long nr_pages , struct
       vmem_altmap *altmap , struct dev_pagemap *pgmap );

like literally that's the whole signature, copy it exactly bestie, it's giving C function realness 💅

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🦋 ARGUMENTS 🦋

• pfn — the starting pageframe. ⚠️ it must be aligned to the start of a section, okay? not "roughly near", not "close enough" — aligned. the vibes must be immaculate.
• nr_pages — how many pages you're removing. and it must be a multiple of section size. yes, the whole section size. don't come at me with a random number 🙈
• altmap — alternative device page map, or NULL if you're using the default memmap. pick one, it's not that deep 💜
• pgmap — device page map, or NULL if it's not ZONE_DEVICE. if it's not a device zone, just pass NULL and move on ✨

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🔥 DESCRIPTION 🔥

so this is a generic helper function, and its whole job is to remove section mappings and sysfs entries for the section of memory we're removing. two things at once, multitasking icon behavior 👑

BUT — and this is the important part, i'm being so serious right now — the caller needs to make sure that pages are marked reserved and that zones are adjusted properly by calling offline_pages. the function does not do that for you. that's on you. that's your moment. don't skip it 😭

tl;dr: __remove_pages is the cleanup crew, offline_pages is the bouncer. you need both. periodt. 💀

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⭐ SEE ALSO ⭐

• Kernel file ./mm/memory_hotplug.c — the source, the mothership, the origin story 🧚
• __add_memory_driver_managed(9)
• add_memory_driver_managed(9)
• try_offline_node(9)
• __remove_memory(9)
• offline_and_remove_memory_ranges(9)

bestie go read those too, iykyk 🌈

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and that's the page! brought to you by ./mm, dated October 2026 — mwah, love u, go mark those pages reserved 💖✨🎀