__memblock_...ge_bottom_up(9)

💅 __memblock_find_range_bottom_up — NAME

okay so bestie, welcome to the Kernel API Manual ✨ — this is the page for __memblock_find_range_bottom_up, and yes the header truncates it like that, we don't talk about it 🙈. Short version: it's the find free area utility in bottom-up 🎀 — it goes hunting for a chunk of free memory, searching from the bottom of the range upward.

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🦋 SYNOPSIS

phys_addr_t __init_memblock __memblock_find_range_bottom_up (phys_addr_t
start , phys_addr_t end , phys_addr_t size , phys_addr_t align , int nid
, enum memblock_flags flags );

that's the whole signature, no cap 💅

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🌸 ARGUMENTS

• start — where the candidate range begins. the starting line, the bottom of the search zone 🫶
• end — where the candidate range ends. plot twist: this one can also be MEMBLOCK_ALLOC_ANYWHERE or MEMBLOCK_ALLOC_ACCESSIBLE, so it's not always a plain endpoint 👀
• size — how big the free area you're looking for needs to be 🍓
• align — the alignment that free area has to have. picky queen behaviour and honestly? iconic ✨
• nid — the nid of the free area you want, and if you pass NUMA_NO_NODE it'll take any node. flexible fr fr 💜
• flags — pick from blocks based on memory attributes. it's giving "choose wisely" 🔥

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🧚 DESCRIPTION

this is the utility that memblock_find_in_range_node calls in, and what it does is find free area bottom-up ⭐ — literally searching upward for a free chunk. lowkey the whole job. main character energy for a helper function, honestly 👑

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🌈 RETURN

• Found address on success 🎉
• 0 on failure 😭

that's it. no in-between, no "maybe". zero means nope 💀

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👑 SEE ALSO

bestie there are SO many siblings, buckle in 🎀 the kernel file ./mm/memblock.c and the memblock overview(9) are the family home, and then:

• __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_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)

go read them, they're all part of the same memblock cinematic universe 🫶 iykyk

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and that's the page!! mwah 💖 this lil guy lives over in ./mm and the version we're looking at is dated October 2026 — so yeah, from the future, slay ⭐ periodt 🎀