Corner cases are slightly non-obvious problems implementing huge pages.  If you think of one, please archive it here so it doesn't come back and bite us later.

 * NUMA-aware allocation - don't want all the memory accesses going through one controller!  See [http://www-941.ibm.com/collaboration/wiki/display/LinuxP/Tuning+stream+with+libhugetlbfs IBM's page about tuning Stream].
 * Fork of an application with huge pages when no huge pages are left - must fail over to small pages.