Well my general idea was to modify shrink_page_list() so that instead
of calling add_to_swap() and then pageout(), anonymous pages would be
added to a compressed cache. I haven't worked out all the specific
details, but I am initially thinking that the compressed cache could
simply repurpose incoming pages to use as the compressed cache storage
(using its own page mapping, similar to swap page mapping), and then
add_to_swap() the storage pages when the compressed cache gets to a
certain size. Pages that don't compress well could just bypass the
compressed cache, and get sent the current route directly to
add_to_swap().