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DAX devices must be converted to use the system-ram mode. Converting a dax
device to a NUMA node suitable for use with system memory can be performed using
following command:
$ sudo daxctl reconfigure-device dax2.0 --mode=system-ram
This will migrate the device from using the device_dax driver to the dax_pmem
driver. The following shows an example output with dax1.0 configured as the default
devdax type and dax2.0 is system-ram:
$ daxctl list
[
{
"chardev":"dax1.0",
"size":263182090240,
"target_node":3,
"mode":"devdax"
},
{
"chardev":"dax2.0",
"size":263182090240,
"target_node":4,
"mode":"system-ram"
}
]
You can now use numactl -H to show the hardware NUMA configuration.
The following example output is collected from a 2-socket system and shows node 4
is a new system-ram backed NUMA node created from persistent memory:
$ numactl -H
available: 3 nodes (0-1,4)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
23 24 25 26 27 56 57 58 59 60 61 62 63 64 65 66 67 68 69
70 71 72 73 74 75 76 77 78 79 80 81 82 83
node 0 size: 192112 MB
node 0 free: 185575 MB
Chapter 10 Volatile Use of persistent MeMory