HMEM DAX: direct access to 'specific purpose' memory

modulename: dax_hmem.ko


Linux Kernel Configuration
└─>Device Drivers
└─>DAX: direct access to differentiated memory
└─>HMEM DAX: direct access to 'specific purpose' memory
In linux kernel since version 5.1 (release Date: 2019-05-05)  
EFI 2.8 platforms, and others, may advertise 'specific purpose'
memory. For example, a high bandwidth memory pool. The
indication from platform firmware is meant to reserve the
memory from typical usage by default. This driver creates
device-dax instances for these memory ranges, and that also
enables the possibility to assign them to the DEV_DAX_KMEM
driver to override the reservation and add them to kernel
"System RAM" pool.

Say M if unsure.

source code: