The man page for shmctl(2) doesn't give a way to resize an existing shared memory segment, so you can't expand it with any of the shared memory modules, since it's a limitation of the OS.

It might be possible with mmap(2), but if other process have already mapped the memory area, then they would have to be notified of the change and unmap/map the memory again. This implies that it would have to be a file on disk so that other processes can unmap/map the same data.

Otherwise, it's has to be something that copies the data between the processes.