Device memory (pmem, HMM, etc...) hotplug support
modulename: memremap.ko
configname: CONFIG_ZONE_DEVICE
Linux Kernel Configuration
└─>Memory Management options
└─>Memory hotplug
└─>Device memory (pmem, HMM, etc...) hotplug support
In linux kernel since version 3.10 (release Date: 2013-06-30)
Device memory hotplug support allows for establishing pmem,
or other device driver discovered memory regions, in the
memmap. This allows pfn_to_page() lookups of otherwise
"device-physical" addresses which is needed for DAX, PCI_P2PDMA, and
DEVICE_PRIVATE features among others.
Enabling this option will reduce the entropy of x86 KASLR memory
regions. For example - on a 46 bit system, the entropy goes down
from 16 bits to 15 bits. The actual reduction in entropy depends
on the physical address bits, on processor features, kernel config
(5 level page table) and physical memory present on the system.
or other device driver discovered memory regions, in the
memmap. This allows pfn_to_page() lookups of otherwise
"device-physical" addresses which is needed for DAX, PCI_P2PDMA, and
DEVICE_PRIVATE features among others.
Enabling this option will reduce the entropy of x86 KASLR memory
regions. For example - on a 46 bit system, the entropy goes down
from 16 bits to 15 bits. The actual reduction in entropy depends
on the physical address bits, on processor features, kernel config
(5 level page table) and physical memory present on the system.