Re: Cache incoherencies

Rogier Wolff (R.E.Wolff@BitWizard.nl)
Fri, 27 Aug 1999 08:51:57 +0200 (MEST)

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Alan Cox wrote:
> > Say i have 12Mb RAM. So that's 3 4Mb pages. When I need an uncached
> > page, I'd map it into the 64M-68M range, mark that range as uncached,
> > and return the pointer in the 64-68M range. Now we have a "hole" in
>
> And the rest of that 4Mb range is loaded with critical data now running
> uncached. Your box crawls like a 286.

But you access it through the other window, which is still cached.

Oh yeah, I'm indeed assuming that you can specify these attributes
based on virtual adresses. If those go by physycal addresses, you're
completely right, and this is not an option.

Roger.

-- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 ** *-- BitWizard writes Linux device drivers for any device you may have! --* ------ Microsoft SELLS you Windows, Linux GIVES you the whole house ------

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