Re: [resent PATCH] Re: very slow parallel read performance

[Alan Cox]

> Ummm... is this really more of an agreement that Daniel's used-once
> patch is a good idea on a system.  Keep a page around if it's used
> once, but drop it quickly if only used once?  But you seem to be

Is there a reason aging alone cannot do most of the work instead. When you
readahead a page you look to age a page that is a a bit over the readahead
window further back in the file if it is in memory, and has no mapped users
- ie its just cache.

That seems to cost us extra lookups in the page cache hashes but push things
in the right direction. 

Alan