For this staging driver, RAMster duplicates code from drivers/staging/zcache
then incorporates changes to the local copy of the code.  For V5, it also
directly incorporates the soon-to-be-removed drivers/staging/zram/xvmalloc.[ch]
as all testing has been done with xvmalloc rather than the new zsmalloc.
Before RAMster can be promoted from staging, the zcache and RAMster drivers
should be either merged or reorganized to separate out common code.

Until V4, RAMster duplicated code from fs/ocfs2/cluster, but this made
RAMster incompatible with ocfs2 running in the same kernel and included
lots of code that could be removed.  As of V5, the ocfs2 code has been
mined and made RAMster-specific, made to communicate with a userland
ramster-tools package rather than ocfs2-tools, and can co-exist with ocfs2
both in the same kernel and in userland on the same machine.