1M hugepage size being registered on Linux

[victora]

Hi Alistair/Jeremy,

I am working on a bug related to 1M hugepage size being registered on 
Linux (Power 8 Baremetal - Garrison).

I was checking dmesg and it seems that 1M page size is coming from 
firmware to Linux.

[    0.000000] base_shift=20: shift=20, sllp=0x0130, avpnm=0x00000000, 
tlbiel=0, penc=2
[    1.528867] HugeTLB registered 1 MB page size, pre-allocated 0 pages

Should Linux support this page size? As afar as I know, this was an 
unsupported page size in the past isn't it? If this should be supported 
now, is there any specific reason for that?

Thanks,

Victor Aoqui
Software Engineer: Linux Kernel Backports
Linux Technology Center
IBM Systems