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To: linux-kernel@vger.kernel.org
From: torvalds@transmeta.com (Linus Torvalds)
Subject: Re: [Lse-tech] Re: 10.31 second kernel compile
Date: Sun, 17 Mar 2002 18:16:47 +0000 (UTC)
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In article <Pine.LNX.4.44L.0203171021090.2181-100000@imladris.surriel.com>,
Rik van Riel  <riel@conectiva.com.br> 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
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