alloc_contig_pages(9)

💅 alloc_contig_pages(9)

okay so bestie, welcome to the Kernel API Manual ✨ this one's a little function called alloc_contig_pages and it's lowkey doing some heavy lifting in ./mm. let's get into it 🫶

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🌸 NAME 🌸

alloc_contig_pages — tries to find and allocate contiguous range of pages 🎀

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✨ SYNOPSIS ✨

struct page * alloc_contig_pages (unsigned long nr_pages , gfp_t
gfp_mask , int nid , nodemask_t *nodemask );

like, that's the whole vibe. four args, one struct page * coming back at you 💖

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🦋 ARGUMENTS 🦋

• nr_pages — how many contiguous pages you wanna allocate. like, no gaps, they gotta be besties and sit next to each other fr fr.
• gfp_mask — the GFP mask 💅 that's the allocation flavour, yk?
• nid — target node 🎯 the node you're actually aiming at.
• nodemask — mask for other possible nodes 🌈 so if nid doesn't work out there's a backup plan, iconic.

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👑 DESCRIPTION 👑

so here's the tea ☕ this routine is a wrapper around alloc_contig_frozen_pages. cute, right?

but bestie, listen — it can't be used to allocate compound pages. not a thing. 🙈 the refcount of each allocated page will be set to one.

and the way you free these bad boys? two options:

• free_contig_range — the easy way, ate 💅
• or by manually calling __free_page on each allocated page — the DIY way, main character energy 🔥

ngl, remember the refcount thing. every single page comes back with refcount one, no cap.

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⭐ RETURN ⭐

pointer to contiguous pages on success 🎉 or NULL if not successful 😭 that's it. that's the return. vibe check passed either way.

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🌈 SEE ALSO 🌈

Kernel file ./mm/page_alloc.c — go read up, iykyk 📖 and like, the whole friend group:

• __get_pfnblock_flags_mask(9)
• get_pfnblock_bit(9)
• get_pfnblock_migratetype(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)
• free_contig_frozen_range(9)
• free_contig_range(9)
• alloc_pages_nolock(9)

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aaaand that's the page, bestie 🧚 this lil slice of ./mm is dated October 2026 and lives under source/version ./mm in the alloc_contig_pages(9) era 💜 go forth and allocate contiguously, slay 💅✨