Hugetlbfs pages are dynamically allocate-able

The presence of contiguous memory will be entirely dependant on the system and work load. You are correct that allocating huge pages becomes more difficult as memory is fragmented. My reply was to the section of the article that said hugetlbfs based huge pages must be set aside at boot time which is not correct for all page sizes. On systems that support them, 1GB and 16GB pages must be reserved at boot, but 2MB, 4MB, and 16MB pages can be allocated any time there is contiguous space.