Compressed caching is the introduction of a new
level into the virtual memory hierarchy.
Specifically, RAM is used to store both an
uncompressed cache of pages in their natural
encoding, and a compressed cache of pages in some
compressed format. By using RAM to store some
number of compressed pages, the effective size of
RAM is increased, and so the number of page faults
that must be serviced by very slow hard disks is
decreased. The main goal is to implement this
compressed caching in Linux 2.4 (2.5).
