Readahead for compressed data

[Phillip Susi]

Jan Kara <jack at suse.cz> writes:

> Well, one of the problems with keeping compressed data is that for mmap(2)
> you have to have pages decompressed so that CPU can access them. So keeping
> compressed data in the page cache would add a bunch of complexity. That
> being said keeping compressed data cached somewhere else than in the page
> cache may certainly me worth it and then just filling page cache on demand
> from this data...

True... Did that multi generational LRU cache ever get merged?  I was
thinking you could use that to make sure that the kernel prefers to
reclaim the decompressed pages in favor of keeping the compressed ones
around.