memblock_alloc_range_nid(9)

💖 memblock_alloc_range_nid(9) 💖

okay bestie, so this is a page from the Kernel API Manual — yes, the kernel, we're doing kernel stuff today, put your hair up — and it's about memblock_alloc_range_nid, which allocates a boot memory block. boot memory is the early stuff, before the fancy allocators wake up, so like... the pre-coffee era of memory management ☕✨

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🌸 NAME 🌸

memblock_alloc_range_nid — allocate boot memory block 🎀

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✨ SYNOPSIS ✨

phys_addr_t memblock_alloc_range_nid (phys_addr_t size , phys_addr_t
align , phys_addr_t start , phys_addr_t end , int nid , bool exact_nid
);

like, that's the whole signature, no cap. returns a phys_addr_t and takes six things 💅

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🫶 ARGUMENTS 🫶

• size — size of memory block to be allocated in bytes. yes bytes. the unit of choice 📏
• align — alignment of the region and the block's size. both. it's giving "alignment of the region and block's size," literally what it says ✨
• start — the lower bound of the memory region to allocate (phys address). the floor 🦋
• end — the upper bound of the memory region to allocate (phys address). the ceiling 🌈
• nid — nid of the free area to find, NUMA_NO_NODE for any node. "idk just put it anywhere" energy 🙈
• exact_nid — control the allocation fall back to other nodes. it's the switch that decides whether we're being picky or not 💀

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👑 DESCRIPTION 👑

The allocation is performed from memory region limited by memblock.current_limit if end == MEMBLOCK_ALLOC_ACCESSIBLE. so like, that's the special value, don't forget it 👀

If the specified node can not hold the requested memory and exact_nid is false, the allocation falls back to any node in the system. flexible. accommodating. a queen who knows when to compromise 💅

For systems with memory mirroring, the allocation is attempted first from the regions with mirroring enabled and then retried from any memory region. mirror first, then whatever, iykyk 🪞✨

In addition, function using kmemleak_alloc_phys for allocated boot memory block, it is never reported as leaks. so the memory leak detector just... minds its business? iconic behaviour honestly 🔥

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⭐ RETURN ⭐

Physical address of allocated memory block on success, 0 on failure. that's it, that's the return. zero means nope 😭

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🦋 SEE ALSO 🦋

the whole friend group, ok buckle up 🫶:

Kernel file ./mm/memblock.c memblock overview(9), __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_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_hugetlb(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).

like. that's 40-something cross-references. we read them all. we don't skip. periodt 💀💖

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ngl bestie, this lives in ./mm and it's dated October 2026, so write that in your notes and go slay your memory allocation 🎀💅✨

ok bye ily, go allocate responsibly 🌸🦋💜