Page size:
- 64/4K? (AArch64 Fedora/Red Hat kernels will differ: 4K for Fedora
for now, 64K for RH, there are a few issues with 64K left for triage)
Fedora is 64K pages on aarch64, not 4K as noted. It's needed for AMD Seattle support.
You can use 4K pages with Seattle, you just have to use 4-level (48-bit VA) tables in order for the idmap to be able to address the physical memory.
Ard Biesheuvel has some patches [1,2] which will allow the idmap to use 4 levels while keeping the rest of the tables as 3-level, which should alleviate any performance impact 4-level tables could have.
Hopefully those will be upstream shortly.
Thanks, Mark.
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/328541.html [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/328542.html