CONFIG_BFIN_WB is not available for thedefaultarchitecture x86.
Result is shown for architecture blackfin
default or selected kernelversion does not have config value CONFIG_BFIN_WB.
Result is shown for kernelversion 5.3.7

Write back

configname: CONFIG_BFIN_WB

Policy
└─>Write back
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
Write Back Policy:
Cached data will be written back to SDRAM only when needed.
This can give a nice increase in performance, but beware of
broken drivers that do not properly invalidate/flush their
cache.

Write Through Policy:
Cached data will always be written back to SDRAM when the
cache is updated. This is a completely safe setting, but
performance is worse than Write Back.

If you are unsure of the options and you want to be safe,
then go with Write Through.