CONFIG_PS3_USE_LPAR_ADDR dramically increases boot time

[Jimi Xenidis]

The following change set:
   http://git.kernel.org/?p=linux/kernel/git/paulus/ 
powerpc.git;a=commit;h=261efc3f178c8c5b55d76208aee1f39ce247f723

setting CONFIG_PS3_USE_LPAR_ADDR (which is the default for PS3)  
changes increases MAX_PHYSADDR_BITS  from 44 to 47 which makes the  
array 8 time bigger and takes way longer for sparse_init() to run on  
simulator.

Is this really the right approach?
Cell is actually 42 so could not the special address space be 43 or 44?

-JX