In-memory B-tree is faster and uses less memory for small keys [1]. However, intrusive binary search trees (BSTs) are much more flexible and are the right choic

In-memory B-tree is faster and uses less memory for small keys [1]. However, intrusive binary search trees (BSTs) are much more flexible and are the right choice for implementing kernels and malloc(). In addition, intrusive BSTs are often used to organize memory blocks scattered around. In-memory B-tree would lose its cache-efficiency in this case anyway. [1] https://attractivechaos.wordpress.com/2008/09/24/b-tree-vs-binary-search-tree/ https://attractivechaos.wordpress.com/2008/09/24/b-tree-vs-b...