Comment 3 for bug 1797187

The "Steps To Reproduce" has been executed in a Bare Metal Dedicated Storage 2+3+2 having both, the same error message as reported and without the error message, depending on the value and CPU core. The system used to initially test was used for CEPH validation, another system is being installed to repeat the steps and give more clarity in the process followed and the results obtained.

For specific details about the process followed including the requests from Erich:
https://github.com/xe1gyq/starlingx/blob/master/bugs/1797187.md

The high level overview of tasks done are:

Bare Metal Overall Huge Pages Information

- From controller-1, look at the number of hosts and memory information for compute-0 via host-memory-list
- From compute-0, look at the memory information via kernel boot arguments (/etc/default/grub /proc/cmdline) and memory information (/proc/meminfo)

Bare Metal 2M Hugepages

- Get default values for compute-0 2M Hugepages via host-memory-list
- Modify to default values for compute-0 2M Hugepages via host-memory-modify:

$ system host-memory-modify compute-0 0 -2M 42477 [Fail]
Processor 0:No available space for 1G vswitch huge page allocation, max 1G vswitch pages: 0
$ system host-memory-modify compute-0 1 -2M 43232 [Ok]

- Decreasing to 512 2M huge pages

$ system host-memory-modify compute-0 0 -2M 512 [Ok]
$ system host-memory-modify compute-0 1 -2M 512 [Ok]

- Going back to default 2M huge pages values

$ system host-memory-modify compute-0 0 -2M 42477 [Fail]
Processor 0:No available space for 1G vswitch huge page allocation, max 1G vswitch pages: 0
$ system host-memory-modify compute-0 1 -2M 43232 [Ok]

Bare Metal 1G Hugepages

- From controller-0, reserve at least one 1G hugepage

$ system host-memory-modify compute-0 0 -1G 1 [Fail]
Processor 0:No available space for new VM hugepage settings.Max 1G pages is 0 when 2M is 42477, or Max 2M pages is 39966 when 1G is 5.

- Reboot, modify bootargs to include: hugepagesz=1G hugepages=2
- reserve at least one 1G hugepage:

$ system host-memory-modify compute-0 0 -1G 1 [Ok]
$ system host-memory-modify compute-0 0 -1G 2 [Ok]

- Verify 1G values

$ system host-memory-show compute-0 0
| Application Huge Pages (1G): Total | 0
| Total Pending | 2
| Available | 0

$ system host-memory-modify compute-0 0 -1G 10 [Ok]

Will get back with more information...