Re: Problem with 1G RAM

MOLNAR Ingo (mingo@chiara.csoma.elte.hu)
Sat, 5 Dec 1998 14:29:00 +0100 (CET)


On Fri, 4 Dec 1998, David S. Miller wrote:

> From: Perry Harrington <pedward@sun4.apsoft.com>
> Date: Fri, 4 Dec 1998 14:58:51 -0800 (PST)
>
> Does any of this make sense? Or am I just off my rocker? I thought
> of dynamicising PAGE_OFFSET for x86, but I figured that Linus, et
> al, would have a fit over performance.
>
> Look at the BTFIXUP stuff we do on sparc32 to see another idea of how
> to taper off most of the performance problems assosciated with a
> dynamic PAGE_OFFSET. (TASK_UNMAPPED_BASE was a real killer before we
> added the BTFIXUP stuff, it put a divide into a critical path).

the problem with this is that x86 CISC instructions are inherently more
difficult to fix up runtime :(

-- mingo

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