Re: [PATCH] vmscan: evict use-once pages first (v2)

Peter Zijlstra
2009-05-04T08:05:28Z

On Fri, 2009-05-01 at 12:35 -0700, Andrew Morton wrote:

> No, I think it still _is_ the case. When reclaim is treating mapped
> and non-mapped pages equally, the end result sucks. Applications get
> all laggy and humans get irritated. It may be that the system was
> optimised from an overall throughput POV, but the result was
> *irritating*.
>
> Which led us to prefer to retain mapped pages. This had nothing at all
> to do with internal impementation details - it was a design objective
> based upon empirical observation of system behaviour.

Shouldn't we make a distinction between PROT_EXEC and other mappings in
this? Because as soon as you're running an application that uses gobs
and gobs of mmap'ed memory, the mapped vs non-mapped thing breaks down.