Hugetlb HPTE hashing weirdness

[Benjamin Herrenschmidt]

> Attached is my somewhat hacky hugetlb test suite.  Build it with 'make
> all'.  I've been reproducing with:
> 	for i in `seq 1 10`; do ./mmap-gettest 1 10; done
> After about the third or fourth iteration, you should start to see test
> failures.

What machine do you use ?

I can reproduce the problem on a g5 here but strangely not on any LPAR
machine I've tested so far (all POWER5)... 

I did find a bug in the hugepage code though I doubt it's the culprit,
I'll test a fix on the g5.

Ben.