Re: [PATCH] mm: fix boundary checking in free_bootmem_core

[Andi Kleen <andi@firstfloor.org>]

"Yinghai Lu" <yhlu.kernel@gmail.com> writes:
> 
> then i tried to reserve 64M or 128M RAM before that, and free that
> before gart/switotble try to allloc_bootmem under 4g.

Sounds like an incredible hack. There are far better ways to do that
for bootmem allocations. e.g. you can just specify a high enough "goal"
That is how swiotlb solves a similar problem (at least before my 
mask allocator rewrite) 

> >  with your improved free_bootmem()
> 
> using phys_to_nid()? it seems we only have that on x86_64.

pfn/page_to_nid() is generic afaik.
 
> also there is assumpation that reserve_bootmem_node, reserver_bootmem
> can not cross the nodes.
> I want to remove that constrient too.

Makes sense, but that will be much more work and should be all separated.

-Andi