Demand faulting for huge pages

Hi Andrew.  Can we give hugetlb demand faulting a spin in the mm tree?
And could people with alpha, sparc, and ia64 machines give them a good
spin?  I haven't been able to test those arches yet.

-Thanks

- htlb-get_user_pages removes an optimization that is no longer valid
when demand faulting huge pages

- htlb-fault moves the fault logic from hugetlb_prefault() to
hugetlb_pte_fault() and find_get_huge_page().

- htlb-acct adds an overcommit check to maintain the no-overcommit
semantics provided by hugetlb_prefault()
-- 
Adam Litke - (agl at us.ibm.com)
IBM Linux Technology Center