Re: mmap vs fs cache

Howard Chu
2013-03-05T23:55:07Z

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/