memblock_alloc_hugetlb(9)

🦋 memblock_alloc_hugetlb — allocate boot memory for HugeTLB pages 🦋

okay so bestie, you're in the Kernel API Manual and this one's giving "early boot, big pages, no drama." it's memblock_alloc_hugetlb(9) and honestly she's iconic in a very specific way. let's get into it ✨

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✨ SYNOPSIS ✨

void * memblock_alloc_hugetlb (phys_addr_t size , int nid , bool
exact_nid );

three args, one pointer back, and yes the return type is void * — keep that in mind, it matters later 💅

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🎀 ARGUMENTS 🎀

• size — how big the memory block you want is, measured in bytes. that's it, that's the whole vibe.
• nid — the nid of the free memory to find. if you're like "idk, anywhere is fine," you pass NUMA_NO_NODE and she'll take any node. queen of flexibility 🫶
• exact_nid — this is the picky one. if true, it will only allocate from the specified nid, no substitutions, no plan B (main character energy fr). if false, the specified nid gets tried first and then all nodes are tried as a fallback. so like, "try my fave first but honestly whatever works" 💖

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🌸 DESCRIPTION 🌸

HugeTLB pages are always aligned by their size, so lowkey the alignment just matches size. no extra math needed, it's giving self-consistent 💅

since this memory is for userspace, mirrored memory is not used — noted, important, don't come for me about it.

the memory is not zeroed. so like, don't assume it's a fresh clean slate, bestie, because it is not 🙈

and the big one: this does not panic if the request can't be satisfied. she simply returns nothing and moves on. no dramatics, no kernel meltdown. periodt.

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⭐ RETURN ⭐

• on success → the virtual address of the allocated memory block 🎉
• on failure → NULL 💀 (and remember: no panic, just NULL, so pls check it, i'm begging)

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🧚 SEE ALSO 🧚

the whole memblock friend group, assembled. kernel file ./mm/memblock.c, plus memblock overview(9), and then, in this exact order, no cap:

• __memblock_find_range_bottom_up(9)
• __memblock_find_range_top_down(9)
• memblock_find_in_range_node(9)
• memblock_find_in_range(9)
• memblock_discard(9)
• memblock_double_array(9)
• memblock_merge_regions(9)
• memblock_insert_region(9)
• memblock_add_range(9)
• memblock_add_node(9)
• memblock_add(9)
• memblock_validate_numa_coverage(9)
• memblock_isolate_range(9)
• memblock_free(9)
• memblock_phys_free(9)
• memblock_setclr_flag(9)
• memblock_mark_hotplug(9)
• memblock_clear_hotplug(9)
• memblock_mark_mirror(9)
• memblock_mark_nomap(9)
• memblock_clear_nomap(9)
• memblock_reserved_mark_noinit(9)
• memblock_reserved_mark_kern(9)
• memblock_mark_kho_scratch(9)
• memblock_clear_kho_scratch(9)
• __next_mem_range(9)
• __next_mem_range_rev(9)
• memblock_set_node(9)
• memblock_alloc_range_nid(9)
• memblock_phys_alloc_range(9)
• memblock_phys_alloc_try_nid(9)
• memblock_alloc_internal(9)
• memblock_alloc_exact_nid_raw(9)
• memblock_alloc_try_nid_raw(9)
• memblock_alloc_try_nid(9)
• __memblock_alloc_or_panic(9)
• memblock_estimated_nr_free_pages(9)
• memblock_is_region_memory(9)
• memblock_is_region_reserved(9)
• memblock_free_all(9)
• reserve_mem_find_by_name(9)
• reserve_mem_release_by_name(9)

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ok that's the whole page!! go forth, allocate your hugetlb boot memory, check for NULL, and remember: not zeroed, not mirrored, not panicking. slay 🌈👑

mwah 💜 — this cutie lives in ./mm, dated October 2026, from the memblock_alloc_hugetlb(9) era of the Kernel API Manual. bye bestie, ily, read the SEE ALSO 🎀