CONFIG_CACHE_B15_RAC is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
Enable the Broadcom Brahma-B15 read-ahead cache controller
modulename: cache-b15-rac.ko
configname: CONFIG_CACHE_B15_RAC
Linux Kernel Configuration
└─>Enable the Broadcom Brahma-B15 read-ahead cache controller
In linux kernel since version 3.10 (release Date: 2013-06-30)
This option enables the Broadcom Brahma-B15 read-ahead cache
controller. If disabled, the read-ahead cache remains off.
controller. If disabled, the read-ahead cache remains off.