Re: vmscan.c heuristic adjustment for smaller systems

[Nick Piggin]

Marc Singer wrote:
> On Sat, Apr 17, 2004 at 04:51:51PM -0700, Andrew Morton wrote:
>
> > Marc Singer <elf@xxxxxxxxx> wrote:
> >
> > > On Sat, Apr 17, 2004 at 04:21:25PM -0700, Andrew Morton wrote:
> > >
> > > > How on earth can it take half a minute to list /proc?
> > >
> > > I've watched the vmscan code at work.  The memory pressure is so high
> > > that it reclaims mapped pages zealously.  The program's code pages are
> > > being evicted frequently.
> >
> > Which tends to imply that the VM is not reclaiming any of that nfs-backed
> > pagecache.
>
>
> I don't think that's the whole story.  They question is why.

swappiness is pretty arbitrary and unfortunately it means
different things to machines with different sized memory.

Also, once you *have* gone past the reclaim_mapped threshold,
mapped pages aren't really given any preference above
unmapped pages.

I have a small patchset which splits the active list roughly
into mapped and unmapped pages. It might hopefully solve your
problem. Would you give it a try? It is pretty stable here.

Nick
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