Re: sparsemem support for mips with highmem

[Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>]

David VomLehn wrote:

> On MIPS processors, the kernel runs in unmapped memory, i.e. the TLB
> isn't even
> used, so I don't think you can use that trick. So, this comment doesn't
> apply to
> all processors.

In that case you have a choice between the overhead of sparsemem lookups in
every pfn_to_page or using TLB entries to create a virtually mapped memmap
which may create TLB pressure.

The virtually mapped memmap results in smaller code and is typically more
effective since the processor caches the TLB entries.