Re: [Lse-tech] Re: 10.31 second kernel compile

[Linus Torvalds]

In article <[e-mail]>,
Rik van Riel  <[e-mail]> wrote:
>
>In other words, large pages should be a "special hack" for
>special applications, like Oracle and maybe some scientific
>calculations ?

Yes, I think so.

That said, a 64kB page would be useful for generic use. 

>Grabbing some bitflags in generic datastructures shouldn't
>be an issue since free bits are available.

I had large-page-support working in the VM a long time ago, back when I
did the original VM portability rewrite.  I actually exposed the kernel
large pages to the VM, and it worked fine - I didn't even need a new
bit, since the code just used the "large page" bit in the page table
directly. 

But it wasn't ever exposed to user space, and in the end I just made the
kenel mapping just not visible to the VM and simplified the x86
pmd_xxx() macros.  The approach definitely worked, though. 

			Linus