MAPLE TREE FLAGS(9)

🌳 Maple tree flags 🌳

okay bestie, welcome to the kernel API manual 💅 this page is literally just the flag glossary for maple trees — the data structure, not the syrup kind (sadly 😭). it's giving "cheat sheet energy" and honestly? iconic. every flag, every mask, every constant, all right here. no cap, nothing skipped. 🫶

✨ THE FLAGS ✨

• MT_FLAGS_ALLOC_RANGE — tracks gaps in this tree 🕳️ like it's keeping receipts on where the empty spots are
• MT_FLAGS_USE_RCU — operate in RCU mode ⚡ the whole tree runs in RCU mode with this one
• MT_FLAGS_HEIGHT_OFFSET — the position of the tree height in the flags 📏 that's where the height value lives inside the flags
• MT_FLAGS_HEIGHT_MASK — the mask for the maple tree height value 🎭 mask goes on, height value gets pulled out
• MT_FLAGS_LOCK_MASK — how the mt_lock is used 🔐 controls how mt_lock gets used
• MT_FLAGS_LOCK_IRQ — acquired irq-safe 🌈 acquired irq-safe, bestie
• MT_FLAGS_LOCK_BH — acquired bh-safe 🦋 acquired bh-safe, no stress

💀 heads up: MT_FLAGS_LOCK_EXTERN means mt_lock is not used — so if you see that flag, don't go looking for the lock, it's not invited to the party 🙈

• MT_FLAGS_LOCK_EXTERN — mt_lock is not used 🚫 the lock is simply not used here
• MAPLE_HEIGHT_MAX — the largest height that can be stored 👑 the biggest height that can be stored, periodt

👀 SEE ALSO 👀

kernel file ./include/linux/maple_tree.h — go read it, it's the main character 📖✨

and then the whole friend group of references, all of them, in order, fr fr:

• MTREE_INIT(9)
• MTREE_INIT_EXT(9)
• mtree_empty(9)
• mas_reset(9)
• mas_for_each(9)
• mas_for_each_rev(9)
• __mas_set_range(9)
• mas_set_range(9)
• mas_set(9)
• mt_init_flags(9)
• mt_init(9)
• mt_clear_in_rcu(9)
• mt_set_in_rcu(9)
• mt_for_each(9)

that's the whole page, bestie, you ate it up 💖 this gem comes to you from ./include/linux and is dated October 2026 — so go forth, set those flags, and slay 🎀🌟