Block device as cache

modulename: bcache.ko

configname: CONFIG_BCACHE

Linux Kernel Configuration
└─>Device Drivers
└─>Multiple devices driver support (RAID and LVM)
└─>Block device as cache
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Allows a block device to be used as cache for other devices; uses
a btree for indexing and the layout is optimized for SSDs.

See Documentation/admin-guide/bcache.rst for details.

source code:
selects
CONFIG_CRC64

depends
CONFIG_MD