Sharable Mempool between processes

[KeithWiles]

Difficulty: Hard

Modify CNDP mempool code to allow multiple processes to share a single mempool across processes. CNDP is a single process model application type and we need to be able to share buffers between processes without needing to share the entire process memory space which is what DPDK does today.

Sharing memory between processes is normally done with mmap() API to create a sharable region of memory. When sharing memory between processes you can not assume the virtual address of the memory space is the same between processes. That means memory pointers are not allowed in the shared memory region. This means the pointer currently being used need to be convert to offsets into the memory region.

The implementation should rely on Linux IPC and existing shared memory infrastructure wherever possible.

It should be possible to send and receive packets using AF_XDP sockets which use a shared UMEM between two or more processes.