Re: page_to_nid not linked in on PAE

[Andi Kleen <ak@linux.intel.com>]

> Jan, Even with out using the PG_head, PG_tail, PG_uncached and
> PG_hwpoison, by allowing the NODES_SHIFT to have a maximum value of 9 on
> 32bit kernel, can still result in the page flags to runout and result in
> this problem. Best solution for now is to limit the NODES_SHIFT to 5. I
> don't know of any platforms that have>  32nodes and where we care about
> 32bit linux kernel. So it should be ok as a fix. If someone in future
> cares about>  32 nodes for 32bit kernel, then we can think of a better
> solution. Do you agree? I copied Andi/Nick for their eyes aswell on
> this.

Seems like the right approach to me. Although it might be better to
use 1 3 or 1..4 or so, just in case someone else adds more page bits
later (I'm sure it'll happen again). Even 8 nodes should be plenty for
32bit.

Acked-by: Andi Kleen <ak@linux.intel.com>

-Andi