mtree_alloc_cyclic(9)

✨ mtree_alloc_cyclic(9) ✨

okay so this is a page from the Kernel API Manual and honestly? it's giving "let me find a little spot in the tree for your entry" energy and i'm obsessed 💅

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🌸 NAME 🌸

mtree_alloc_cyclic — bestie, this is literally the "find somewhere to store this entry in the tree" function 🎀

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🦋 SYNOPSIS 🦋

int mtree_alloc_cyclic (struct maple_tree *mt , unsigned long *startp ,
void *entry , unsigned long range_lo , unsigned long range_hi , unsigned
long *next , gfp_t gfp );

like, that's the whole vibe right there ✨

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💖 ARGUMENTS 💖

• mt — the maple tree 🌳 (yes queen, THE tree)
• startp — pointer to ID, no cap
• entry — the entry you're storing, the main character fr
• range_lo — lower bound of the range we're searching 🍓
• range_hi — upper bound of the range we're searching 🌈
• next — pointer to the next ID to allocate 👑
• gfp — the GFP_FLAGS to use for allocations 🧚

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🔥 DESCRIPTION 🔥

so what it does is: it finds an empty entry in mt after next, stores the new index into the id pointer, stores the entry at that index, and then updates next. literally a whole little glow-up sequence 💫

⚠️ important bestie: mt must be initialized with the MT_FLAGS_ALLOC_RANGE flag. no flag, no vibes 😭

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⭐ CONTEXT ⭐

any context at all — she's flexible like that 🫶. it takes and releases the mt.lock. it may sleep if the gfp flags permit 😴

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💀 RETURN 💀

• 0 — allocation succeeded without wrapping, slay ✨
• 1 — allocation succeeded after wrapping, still ate 💅
• -ENOMEM — memory could not be allocated, tragic, we hate to see it 😭
• -EINVAL — mt cannot be used, not it 🚩
• -EBUSY — there are no free entries, the tree is FULL, respectfully 💀

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👑 SEE ALSO 👑

kernel file ./lib/maple_tree.c and the whole friend group:

• mas_prealloc_calc(9)
• mas_wr_preallocate(9)
• mas_insert(9)
• mas_alloc_cyclic(9)
• mas_walk(9)
• mte_dead_walk(9)
• mt_free_walk(9)
• mas_store(9)
• mas_store_gfp(9)
• mas_store_prealloc(9)
• mas_preallocate(9)
• mas_next(9)
• mas_next_range(9)
• mt_next(9)
• mas_prev(9)
• mas_prev_range(9)
• mt_prev(9)
• mas_pause(9)
• mas_find_setup(9)
• mas_find(9)
• mas_find_range(9)
• mas_find_rev_setup(9)
• mas_find_rev(9)
• mas_find_range_rev(9)
• mas_erase(9)
• mas_nomem(9)
• mas_nomem_nofail(9)
• mtree_load(9)
• mtree_store_range(9)
• mtree_store(9)
• mtree_insert_range(9)
• mtree_insert(9)
• mtree_erase(9)
• __mt_dup(9)
• mtree_dup(9)
• __mt_destroy(9)
• mtree_destroy(9)
• mt_find(9)
• mt_find_after(9)

like, that's the entire group chat, everyone showed up 🫶✨

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💖 that's the whole page bestie, hope it ate 💖

this iconic little slice of documentation lives in ./lib, dated October 2026, and you can find her filed under mtree_alloc_cyclic(9) — periodt 🌟🎀