munlockall reenables paging for all pages mapped into the address space
of the calling process.
Memory locks do not stack, i.e., pages which have been locked several times by
calls to mlock or mlockall will be unlocked by a single call to
munlockall. Pages which are mapped to several locations or by several
processes stay locked into RAM as long as they are locked at least at one
location or by at least one process.
On POSIX systems on which mlockall and munlockall are available,
_POSIX_MEMLOCK is defined in <unistd.h> .