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].
* STREAM and hugetlb is a huge issue unless you have chipset level interleave no matter what
* Fork of an application with huge pages when no huge pages are left - must fail over to small pages.
* mmap of a file that is partially in cache already
* mmap of a file that then gets replaced on disk
(say glibc text and then glibc gets upgraded to a newer version)
* MAP_GROWSDOWN for stacks including automatic growth
* mprotect to executable (scenario: dlopen of a shared lib that
requires executable stack, causing all thread stacks to be
mprotected executable)
* write() of mmaped area to the same file at an offset either
inside or outside the same 2Mb page
* same but for an O_DIRECT write
* same but for AIO write
* sendfile() of a non-4Kb region
* truncate of 4Mb mmaped file to 1Mb, then truncate to 1.5Mb
then 0.5Mb (creates a sparse file)
* mmap of a 2Mb region in 2 parts: first 1Mb gets mmaped writable private,
second 2Mb gets mmaped shared writable; then write a few bytes to each part
