Re: swapping and the value of /proc/sys/vm/swappiness

Marcelo Tosatti
2004-09-14T22:03:56Z

On Tue, Sep 14, 2004 at 11:31:53AM -0700, Florin Andrei wrote:
> On Mon, 2004-09-06 at 16:27, Andrew Morton wrote:
> > Con Kolivas <kernel@kolivas.org> wrote:
>
> > > The change was not deliberate but there have been some other people report
> > > significant changes in the swappiness behaviour as well (see archives). It
> > > has usually been of the increased swapping variety lately. It has been
> > > annoying enough to the bleeding edge desktop users for a swag of out-of-tree
> > > hacks to start appearing (like mine).
> >
> > All of which is largely wasted effort.
>
> >From a highly-theoretical, ivory-tower perspective, maybe; i am not the
> one to pass judgement.
> >From a realistic, "fix it 'cause it's performing worse than MSDOS
> without a disk cache" perspective, definitely not true.
>
> I've found a situation where the vanilla kernel has a behaviour that
> makes no sense:
>
> http://marc.theaimsgroup.com/?l=linux-kernel&m=109237941331221&w=2
> http://marc.theaimsgroup.com/?l=linux-kernel&m=109237959719868&w=2
> http://marc.theaimsgroup.com/?l=linux-kernel&m=109238126314192&w=2
>
> A patch by Con Kolivas fixed it:
>
> http://marc.theaimsgroup.com/?l=linux-kernel&m=109410526607990&w=2
>
> I cannot offer more details, i have no time for experiments, i just need
> a system that works. The vanilla kernel does not.

Have you tried to decrease the value of /proc/sys/vm/swappiness
to say 30 and see what you get?

Andrew's point is that we should identify the problem - Con's patch
rewrites swapping policy.