SymptomsStart a Linux VM with the hotplug turned on, and try to increase the amount of RAM for it.
As a result, the memory will fail to be initialized in the guest OS. The following errors will appear in the dmesg output:
Hotplug Mem Device
0020000000 - 0040000000 page 2M
kacpi_notify: page allocation failure. order:9, mode:0x80d0
Pid: 17, comm: kacpi_notify Not tainted 2.6.32-71.el6.x86_64 #1
The issue is with the vanilla Linux kernel and depends on the initial RAM amount of the virtual machine.
The greater the amount of RAM available to the virtual machine initially, the less probability there is of the issue occurring.
The issue with memory remapping on the RAM hotplug has been fixed since the release of the 2.6.38 kernel.