Re: Might refill_inactive_zone () be too aggressive?

[Marc Singer <elf@buici.com>]

On Sat, Apr 17, 2004 at 11:33:25AM -0700, William Lee Irwin III wrote:
> On Sat, Apr 17, 2004 at 11:10:42AM -0700, William Lee Irwin III wrote:
> >> I'm not sure it's expected. Maybe this patch fares better?
> 
> On Sat, Apr 17, 2004 at 11:28:38AM -0700, Marc Singer wrote:
> > Ah, that's a much different thing.  That works for me.  Is that
> > something you'd want to put into the kernel?
> 
> Since we have a coherent story about this working for you, I think
> we should probably send it upstream for review. I don't have a
> particular opinion about it being the right thing to do, as since it's
> a policy decision, it's rather arbitrary.
> 
> If this is important to you, it may help to numerically quantify your
> results, e.g. some before/after benchmark/throughput/whatever numbers.

That's a difficult thing to do.  My test setup uses an NFS root and
the IO is over NFS.  Due to some oddities in the NFS code, performance
is variable to a degree that does not make for good timing
comparisons.  I'm looking for a way to enable TCP nfsroot mounts.
Once this is working, I may be able to get some reliable numbers.

It's your call about waiting for performance numbers.  As soon as I
have better data, I'll post it.  Setting the swappiness flag does
work, so I can give my users something for now.  It is possible that
this will work for all cases that I'm ever going to see.  Setting
swappiness to zero and the user mapping 50% of RAM will once again
cause reclaim_mapped to go into action.  The difference is that with
swappiness of 60, I'm not allowed to keep any mapped pages in RAM.  At
swappiness of 0, I'm allows to keep half of total RAM mapped.

Cheers.
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