review(XS): 7087583: Hotspot fails to allocate heap with mmap(MAP_HUGETLB)

[Igor Veresov]

Hotspot will fail allocating the heap on linux >= 2.6.32 if there're more than 1 large page present but not enough to cover all the heap. The solution is to try small pages if mmap(MAP_HUGETLB) fails and also apply madvise(MADV_HUGETLB) in case some pages are freed by the time we touch this space. 

Webrev: http://cr.openjdk.java.net/~iveresov/7087583/webrev.00/

Thanks!
igor