Re: [Lhms-devel] Re: [RFC] buddy allocator without bitmap [3/4]

[Dave Hansen <haveblue@us.ibm.com>]

On Thu, 2004-08-26 at 17:05, Hiroyuki KAMEZAWA wrote:
> Currently, I think zone->nr_mem_map itself is very vague.
> I'm now looking for another way to remove this part entirely.
> 
> I think mem_section approarch may be helpful to remove this part,
> but to implement full feature of CONFIG_NONLINEAR,
> I'll need lots of different kind of patches.
> (If mem_map is guaranteed to be contiguous in one mem_section)

This is definitely a true assumption right now.  

> 1. Now, I think some small parts, some essence of mem_section which
>    makes pfn_valid() faster may be good.

The only question is what it will take when there's a partially populate
mem_section.  We'll almost certainly have to allow it, but the real
question is whether or not we will ever have a partially populated one
that's not at the end of memory.  

> And another way,
> 
> 2. A method which enables page -> page's max_order calculation
>    may be good and consistent way in this no-bitmap approach.
> 
> But this problem would be my week-end homework :).

Instead of adding more stuff to the mem_section, we might be able to
(ab)use more stuff in the mem_map's mem_map, like I am with
page->section right now.  

-- Dave