Re: Patch to reorder functions in the vmlinux to a defined order

[Rene Herman <rene.herman@keyaccess.nl>]

Linus Torvalds wrote:

> The real issue is the _physical_ address. Nothing else matters.
>
> If the TLB splitting on the fixed MTRRs is an issue, it depends entirely 
> on what physical address the kernel resides in, and the virtual address is 
> totally inconsequential.
>
> So playing games with virtual mapping has absolutely no upsides, and it 
> definitely has downsides.

The notion was that having a fixed virtual mapping of the kernel would 
allow it to be loaded anywhere physically without needing to do actual 
address fixups. The bootloader could then for example at runtime decide 
to load the kernel at 16MB if the machine had enough memory available, 
to free up ZONE_DMA. Or not do that if running on a <= 16MB machine.

Or the kdump "host" kernel would make that decission, as it seems the 
want is shared with them. Eric Biederman said that fixups aren't that 
bad though...

Rene.

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