Re: [PATCH] x86: mtrr cleanup for converting continuous to discrete - auto detect v2

From: Yinghai Lu
Date: Thu May 01 2008 - 17:27:02 EST


On Thu, May 1, 2008 at 2:10 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>
> Yinghai Lu wrote:
>
> > On Thu, May 1, 2008 at 12:42 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> >
> > > Yinghai Lu wrote:
> > >
> > >
> > > > loop mtrr chunk_size and gran_size from 1M to 2G to find out optimal
> > > >
> > > value.
> > > Why stopping at 2 GB?
> > >
> >
> > if you select 4g for chunk size, we don't need to convert that from
> > continuous to discrete to make X server driver happen.
> >
> > actually the code could support any chunk_size...
> >
> > for example: 16 g system
> > orginal:
> > 0-4g WB
> > 3.5g-4g UC
> > 4g-8g WB
> > 8g-16g WB
> > 16g-16.5g WB
> >
> > if you set chunk size to 16g, and gran size <= 512M
> > you will get
> > 0-16g WB
> > 3.5g-4g UC
> > 16g-16.5g WB
> >
> >
>
> Yes, 16 GB systems are already mainstream; 32 GB is common, so I don't see
> any reason to stop at 2 GB. Instead, it should loop up to the physical
> address size.

but our objective is that has 0xd0000000-0xe0000000 (WC) not to be
overlapping with other MTRR entries (UC)..

YH
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