Transparent Huge Pages

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Transparent Huge Page support for MIPS is currently under development. THP is currently planned to only be available for 64-bit kernels. A git tree contains the development code.

Hardware requirements

Only R4000-style TLBs are supported. R8000 support may be added in the distant future. The NEC VR41xx processors have such a TLB but do not support the necessary huge page size not even for 4kB base page size so huge page support is not possible for them.

Size of Huge Pages

Due to the page table layout doubling the base page size means the huge page size will increase by a factor of 8. These are the numbers:

Base Page Size Huge Page Size Comments
4kB 2MB
8kB 8MB R8000 and Cavium cnMIPS cores only
16kB 32MB
32kB 128MB Cavium cnMIPS cores only
64kB 512MB

Only the very largest systems will gain from enabling huge page support with a very large base page size.

See also