Open MPI defines its own malloc (by default), so malloc of glibc
is not called.

But, without calling malloc of glibc, the allocator of libhugetlbfs
to back text and dynamic data by large pages, e.g., 16MB pages on
POWER systems, is not used.

Indeed, we can build Open MPI with --with-memory-manager=none.

I am wondering the feasibility of turning the memory manger on
and off dynamically at runtime as a new feature?

Thanks,
Peter Wong