Support for on-demand read

configname: CONFIG_CACHEFILES_ONDEMAND

Linux Kernel Configuration
└─>File systems
└─>Caches
└─>Support for on-demand read
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
This permits userspace to enable the cachefiles on-demand read mode.
In this mode, when a cache miss occurs, responsibility for fetching
the data lies with the cachefiles backend instead of with the netfs
and is delegated to userspace.

If unsure, say N.