CONFIG_EMU_SIZE is not available for thedefaultarchitecture x86.
Result is shown for architecture s390
default or selected kernelversion does not have config value CONFIG_EMU_SIZE.
Result is shown for kernelversion 6.9.9

NUMA emulation memory chunk size

configname: CONFIG_EMU_SIZE

Linux Kernel Configuration
└─>Processor type and features
└─>Select NUMA modes
└─>NUMA emulation memory chunk size
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Select the default size by which the memory is chopped and then
assigned to emulated NUMA nodes.

This can be overridden by specifying

emu_size=<n>

on the kernel command line where also suffixes K, M, G, and T are
supported.