Q: PAGE_CACHE_SIZE?

[Eric W. Biederman]

Who's idea was it start the work to make the granularity of the page
cache larger?

(a) It can save on finding multiple pages
(b) allows larger internal fragmentation of memory.
(c) Isn't needed if you just need a large chunk of the page
    cache at a time.  (It isn't hard to tie 2 or more pages to
    together if you need to).

This is something I'm stumbling over porting patches for large
files in the page cache from 2.2.5 to to 2.3.3.

I guess if it's worth it I would like to talk with whoever is
responsible so we can coordinate our efforts.  

Otherwise I would like this code dropped. 

Non-page cache aligned mappings sound great until you
(a) squeeze the extra bits out of the vm_offset and make it an index
into the page cache, and
(b) realize you need more bits to say how far you are into a page.

Eric