Existing GPU API's are sadly not conducive to this kind of memory mapping with automated swap-in. The closest thing you get AIUI is "sparse" allocations in VRA

Existing GPU API's are sadly not conducive to this kind of memory mapping with automated swap-in. The closest thing you get AIUI is "sparse" allocations in VRAM, such that only a small fraction of your "virtual address space" equivalent is mapped to real data, and the mapping can be dynamic.