Re: mmap vs fs cache

[Howard Chu <hyc@symas.com>]

Howard Chu wrote:
> 2 questions:
>     why is there data in the FS cache that isn't owned by (the mmap of) the
> process that caused it to be paged in in the first place?
>     is there a tunable knob to discourage the page cache from stealing from the
> process?

This Unmapped page cache control http://lwn.net/Articles/436010/ sounds like 
it might have been helpful here. I.e., having a way to prioritize so that 
unmapped cache pages get reclaimed in preference to mapped pages could help. 
Though I still don't understand why these pages in the cache aren't mapped in 
the first place.

-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/