CONFIG_INTERVAL_TREE (not configurable)

modulename: interval_tree.ko

configname: CONFIG_INTERVAL_TREE

Linux Kernel Configuration
└─>Library routines
└─>INTERVAL_TREE
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Simple, embeddable, interval-tree. Can find the start of an
overlapping range in log(n) time and then iterate over all
overlapping nodes. The algorithm is implemented as an
augmented rbtree.

See:
source code:
lib/interval_tree.c