alloc_pages_exact_nid(9)

✨ alloc_pages_exact_nid(9) ✨

okay bestie, welcome to the Kernel API Manual 💖 this one's a little kernel function that's lowkey obsessed with one specific node. let's get into it 🎀

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🌸 NAME 🌸

alloc_pages_exact_nid — allocate an exact number of physically-contiguous pages on a node. no cap, that's literally the whole vibe ✨

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🦋 SYNOPSIS 🦋

void * alloc_pages_exact_nid (int nid , size_t size , gfp_t gfp_mask );

like... it takes three things and gives you a pointer, slay 💅

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🎀 ARGUMENTS 🎀

• nid — the preferred node ID where memory should be allocated 👑 it's giving "i have a favourite and it's this node"
• size — the number of bytes to allocate 📏 exact bytes, we don't do vibes-based sizing here
• gfp_mask — GFP flags for the allocation, and bestie listen to me: must not contain __GFP_COMP 🚫 like, hard no, do not pass that

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💜 DESCRIPTION 💜

so it's like alloc_pages_exact, but it tries to allocate on node nid first before falling back. that's it, that's the whole plot 🫶 highkey simple, highkey iconic.

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🌈 RETURN 🌈

pointer to the allocated area, or NULL in case of error 😭 so yeah, always check your pointer, fr fr.

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⭐ SEE ALSO ⭐

the whole kernel crew, assembled 🧚 and yeah, kernel file ./mm/page_alloc.c is where the magic lives:

• __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)
• 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)

like... a whole friend group 😭 love that for them 💕

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💀 reminder bestie: gfp_mask must not contain __GFP_COMP. i'm not gonna say it a third time... okay maybe i will. don't do it 🙈

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🍓 sign-off 🍓

that's the page!! it lives in ./mm 💖 and this cutie was dated October 2026 ⭐ see you in the next manpage, mwah 🧚‍♀️💅✨