Nikita Danilov wrote:

>Nick Piggin writes:
> > 
>
>[...]
>
> > 
> > But those cold mapped pages are basically ignored until the
> > reclaim_mapped threshold, however they do continue to have their
> > referenced bits cleared - hence page_referenced check should
> > become a better estimation when reclaim_mapped is reached, right?
>
>Right.
>


I still am a bit skeptical that the LRU lists are actually LRU,
however I'm running out of other explainations for your patch's
improvements :)

One ideas I had turns out to have little effect for kbuild, but
it might still be worth including?

When reclaim_mapped == 0 mapped referenced pages are treated
the same way as mapped unreferenced pages, and the referenced
info is thrown out. Fixed by not clearing referenced bits.