CONFIG_HUGETLB_PAGE_FREE_VMEMMAP is not available for thedefaultarchitecture x86.
Result is shown for architecture 64BIT
default or selected kernelversion does not have config value CONFIG_HUGETLB_PAGE_FREE_VMEMMAP.
Result is shown for kernelversion 6.9.9

CONFIG_HUGETLB_PAGE_FREE_VMEMMAP (not configurable)

modulename: hugetlb_vmemmap.ko

configname: CONFIG_HUGETLB_PAGE_FREE_VMEMMAP

Linux Kernel Configuration
└─>File systems
└─>Pseudo filesystems
└─>HUGETLB_PAGE_FREE_VMEMMAP
In linux kernel since version 5.14 (release Date: 2021-08-29)  
source code:
mm/hugetlb_vmemmap.c