What does "kernel: reserve_memtype failed 0xdffff000-0xe0001000, track write-back, req write-back" message imply?

Issue

• Following messages were observed on the server:-

# less var/log/messages | grep -i conflicting
Jul  6 03:47:58 server01 kernel: cpuid:24469 conflicting memory types dffff000-e0001000 write-back<->uncached-minus
Jul  6 04:17:58 server01 kernel: cpuid:29508 conflicting memory types dffff000-e0001000 write-back<->uncached-minus
Jul  6 04:47:58 server01 kernel: cpuid:2092 conflicting memory types dffff000-e0001000 write-back<->uncached-minus
Jul  6 05:17:58 server01 kernel: cpuid:7684 conflicting memory types dffff000-e0001000 write-back<->uncached-minus

# less var/log/messages | grep -i "reserve_memtype"
Jul  6 03:47:58 server01 kernel: reserve_memtype failed 0xdffff000-0xe0001000, track write-back, req write-back
Jul  6 04:17:58 server01 kernel: reserve_memtype failed 0xdffff000-0xe0001000, track write-back, req write-back
Jul  6 04:47:58 server01 kernel: reserve_memtype failed 0xdffff000-0xe0001000, track write-back, req write-back
Jul  6 05:17:58 server01 kernel: reserve_memtype failed 0xdffff000-0xe0001000, track write-back, req write-back