Why do InfiniBand or RDMA programs report "unable to allocate memory" when there is plenty of memory free?

Release Found: All versions of Red Hat Enterprise Linux with InfiniBand/RDMA support

Solution

InfiniBand or RDMA applications need to be able to allocate memory in a special way.  The amount of memory free in the system is only part of the picture.  A normal application can allocate memory without worrying about whether or not the memory it allocated is curre...