Trustworthy Systems

A new virtual memory implementation for L4/MIPS


Cristan Szmajda

    School of Computer Science and Engineering
    Sydney 2052, Australia


Title: A New Virtual Memory Implementation for L4/MIPS Author: Cristan Szmajda School of Computer Science and Engineering, The University of New South Wales, Sydney 2052, Australia, Abstract: This thesis adapts a new data structure, the level and path compressed trie, for use as a page table. Path compression is a technique also applied in the guarded page table, used in the present implementation of the L4/MIPS micro-kernel. Level compression is a recent technique which reduces the depth of guarded page tables so that page table look-up in dense address space distributions can potentially be reduced to only one or two array indexing operations. Like hierarchical page tables, the GPT and LPC trie have natural support for super-pages provided by newer architectures. Support for super-pages increases the coverage of the hardware TLB, decreasing the frequency of TLB misses. The new structure will replace the current virtual memory sub-system of the L4/MIPS micro-kernel. The principle L4/MIPS data structures are also re-designed for efficiency and reduced memory usage. The new implementation is substantially simpler and is designed to be safe in pre-emptable and SMP kernels.

BibTeX Entry

    address          = {Sydney, Australia},
    author           = {Cristan Szmajda},
    keywords         = {GPT, Patricia trie, level compression, path compression, varibale node size, multiple page sizes},
    month            = nov,
    note             = {Available from publications page at \url{}},
    paperUrl         = {},
    school           = {School of Computer Science and Engineering},
    title            = {A New Virtual Memory Implementation for {L4/MIPS}},
    year             = {1999}