[SXX]

> Ideally then one should be able to use spare VRAM as a second level RAM - an area to page out things to before disk.

It's already possible on Linux. You can use SWAP file instead of partition and there also SWAP priorities available.

[AaronFriel]

I've found that putting swap files on things that don't behave like filesystems can cause interesting behaviors. In this case, all writes to the file would go through the VFS. I imagine there could be some curious issues if that write path has any allocations or significant amount of mutation in it.

I would trust more something that got rid of the VFS layer and simply allowed VRAM to be used directly as a second level below RAM using the transcendental memory model.

[wtallis]

And even some otherwise fairly ordinary filesystems don't support swap files (e.g. btrfs).