Ridiculous idea: Cache as ramdisk?

[Justin C. Sherrill]

ibotty wrote:

> b) he wants a possibility to retain a specific file in the cache.
> this can be generalized to the idea, that each file has different
> buffer-cache priority.

Would softupdates' snapshot ability approximate this?  i.e. Put a snapshot
into memory, and then only initial accesses would cause a disk read.  I'm
relatively sure someone beat me to this thought.