get_pfnblock_migratetype(9)

💅 get_pfnblock_migratetype(9) — a Kernel API Manual moment

okay so bestie, welcome to the <pink>Kernel API Manual</pink> ✨ today's main character is get_pfnblock_migratetype and honestly she's lowkey iconic for how much work she saves you 🫶

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🌸 NAME 🌸

get_pfnblock_migratetype — returns the migratetype of a pageblock 💖 that's it, that's the vibe check

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✨ SYNOPSIS ✨

enum migratetype get_pfnblock_migratetype (const struct page *page ,
unsigned long pfn );

look at her signature, so clean, so demure 🎀

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🦋 ARGUMENTS 🦋

• page — the page that lives inside the block you're curious about 👀 she's your "where am I" coordinate
• pfn — the target page frame number 🎯 literally the number, the pfn in question

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⭐ RETURN ⭐

the migratetype of the pageblock 💫 that's what you get back, no cap

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💜 DESCRIPTION 💜

okay so here's the tea: use get_pfnblock_migratetype when you, the caller, already have both page and pfn sitting right there in your hands 🙌 because then you get to skip a whole page_to_pfn call — and honestly? saving a call like that is so satisfying, it's giving efficiency, it's giving "I already did the work" 😌🔥

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🔥 SEE ALSO 🔥

the friend group 🌈 all of these live in the Kernel file ./mm/page_alloc.c and honestly they're all worth a follow:

• __get_pfnblock_flags_mask(9)
• get_pfnblock_bit(9)
• __set_pfnblock_flags_mask(9)
• set_pfnblock_bit(9)
• clear_pfnblock_bit(9)
• set_pageblock_migratetype(9)
• __move_freepages_block_isolate(9)
• __putback_isolated_page(9)
• __free_pages(9)
• free_pages(9)
• alloc_pages_exact(9)
• alloc_pages_exact_nid(9)
• free_pages_exact(9)
• nr_free_zone_pages(9)
• nr_free_buffer_pages(9)
• find_next_best_node(9)
• free_reserved_pages(9)
• setup_per_zone_wmarks(9)
• __free_contig_range(9)
• alloc_contig_frozen_range(9)
• alloc_contig_range(9)
• alloc_contig_frozen_pages(9)
• alloc_contig_pages(9)
• free_contig_frozen_range(9)
• free_contig_range(9)
• alloc_pages_nolock(9)

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and that's the whole page, bestie, you ate that 🍓 source is ./mm, version date October 2026, and yes it's still called get_pfnblock_migratetype(9) because legends don't change their names 👑💅 bye mwah 🎀