Filesystem caching on files

modulename: cachefiles.ko

configname: CONFIG_CACHEFILES

Linux Kernel Configuration
└─>File systems
└─>Caches
└─>Filesystem caching on files
In linux kernel since version 2.6.30 (release Date: 2009-06-09)  
This permits use of a mounted filesystem as a cache for other
filesystems - primarily networking filesystems - thus allowing fast
local disk to enhance the speed of slower devices.

See Documentation/filesystems/caching/cachefiles.txt for more
information.

source code: