Linux 2.6.39-rc3

Joerg Roedel joro at 8bytes.org
Wed Apr 13 15:22:07 PDT 2011


On Wed, Apr 13, 2011 at 03:01:10PM -0700, H. Peter Anvin wrote:
> On 04/13/2011 02:50 PM, Joerg Roedel wrote:
> > On Wed, Apr 13, 2011 at 01:48:48PM -0700, Yinghai Lu wrote:
> >> -	addr = memblock_find_in_range(0, 1ULL<<32, aper_size, 512ULL<<20);
> >> +	addr = memblock_find_in_range(0, 1ULL<<32, aper_size, 512ULL<<21);
> > 
> > Btw, while looking at this code I wondered why the 512M goal is enforced
> > by the alignment. Start could be set to 512M instead and the alignment
> > can be aper_size as it should. Any reason for such a big alignment?
> > 
> > 	Joerg
> > 
> > P.S.: The box is still in the office, I will try this debug-patch
> >       tomorrow.
> 
> The only reason that I can think of is that the aperture itself can be
> huge, and perhaps 512 MiB is the biggest such known. 

Well, that would work as well by just using aper_size as alignment, the
aperture needs to be aligned on its size anyway. This code only runs
when Linux allocates the aperture itself and if I am mistaken is uses
always 64MB when doing this.

	Joerg



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