migrate_device_pfns(9)

🦋 migrate_device_pfns(9) 🦋

okay bestie, welcome to the Kernel API Manual ✨ this one's a kernel function, so grab your lil drink and let's get into it 💅

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💖 NAME 💖

migrate_device_pfns — migrate device private pfns to normal memory.

like, it literally takes device private pfns and moves them back to normal memory, no cap 🫶

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🌸 SYNOPSIS 🌸

int migrate_device_pfns (unsigned long *src_pfns , unsigned long npages );

there she is 👑 returns an int, takes two args, iconic behaviour fr fr

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🎀 ARGUMENTS 🎀

• src_pfns — a pre-populated array of source device private pfns to migrate. yes bestie, pre-populated — you gotta fill it in yourself before you call, that's the whole vibe 💖
• npages — the number of pages to migrate. just a count, lowkey simple, and we love that for us ✨

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🔥 DESCRIPTION 🔥

so here's the tea ☕ — this function is similar to migrate_device_range, except it's got one extra trick: it supports a non-contiguous pre-populated array of device pages to migrate 🧚

the way that migrate_device_range handles things vs. the way this one just takes your whole array as-is… literally the main character energy of this page 💅 like, the pages don't have to be all lined up next to each other in the array — non-contiguous is the moment, and honestly? slay.

ngl bestie, the pre-populated part in the ARGUMENTS is doing a lot of heavy lifting here — the array has to be ready before you call, and the pages in it don't have to be contiguous. read that twice, iykyk 👑

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🌈 SEE ALSO 🌈

• Kernel file ./mm/migrate_device.c 🍓 (yes, the actual file, go peek)
• migrate_vma_split_folio(9)
• migrate_vma_setup(9)
• migrate_vma_insert_huge_pmd_page(9)
• migrate_device_pages(9)
• migrate_vma_pages(9)
• migrate_vma_finalize(9)
• migrate_device_range(9)

all the siblings in the migrate family, go say hi to them too 🫶💜

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and that's a wrap, bestie 🎀 this lil page lives in ./mm, stamped October 2026, and yeah — it's still called migrate_device_pfns(9), and it always will be 💅✨ periodt.