Re: [PATCH]: Allow Xen to boot/run on large memory (>64G) machines

[Chris Lalancette <clalance@redhat.com>]

Keir Fraser wrote:
> On 22/2/07 10:33, "Jan Beulich" <jbeulich@novell.com> wrote:
> 
> 
>>The page allocator changes that I posted a while back probably haven't
>>been looked at so fat, given the above comments. The patch that kills the
>>DMA pool changes x86-64 to allocate the dom0 memory without restriction
>>(i386 has to remain restricted, yet not because of DMA address issues, but
>>in order to be able to see the memory in the 1:1 mapping).
> 
> 
> Oh, good point. :-) And it sounds like it makes sense to leave this alone
> for now and leave it to your patches.
> 

Ah, OK.  That will address the second concern.  Jan's right, I didn't actually
look at those patches.  Thanks for pointing them out.

> 
> It makes sense for the boot allocator to prefer to allocate from high memory
> if it can, rather then using what is currently the DMA pool (and, after your
> patches are applied, will be from relatively-narrow-address-width pools). So
> I think this patch is good and narrow enough in scope to go straight in
> (although I think the behaviour of alloc_boot_pages() should be changed
> rather than adding a new allocator function).

Yeah, I wasn't quite sure how far to go with this.  The frame table was the
worst offender, so I just went after that.  I can whip up a quick patch and test
it out here, changing the alloc_boot_pages() to always allocate from the top.

By the way, I assume we only want to do this for x86_64, yes?

Chris Lalancette