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Re: Re: Debian BSD.. cool idea

On Mon, Jan 31, 2000 at 07:56:04PM -0500, Dan Papasian wrote:
> Are you suggesting to use the linux compatiblity mode to make
> mismatched worlds and kernels less of a problem? I'm not seeing the
> logic in that.

The context is how to produce a debian/bsd system. Someone suggested
that the changes between different BSD releases would diminish both
Debian and BSD to the point where neither would be served. I suggested
using the linux compatability library to base the distribution on would
be sufficient to address this problem.

> > I believe this is false as of Linux 2.2. I seem to recall Stephen
> > Tweedie spending some significant time tuning this aspect of the
> > system prior to the release of 2.2.
> >
> > The basic strategy is to swap aged pages out, but leave enough
> > information behind such that if that page is hit before the
> > underlying memory is reused it can be trivially made available
> > again.

> How trivially can it be made available?

Just restore the mapping.

> Isn't it more logical to not touch the page in physical and only
> swap a copy of it out, then when another page wants physical you can
> quickly kill the original?

You'd have to ask Stephen Tweedie.  I recall reading his explanation
of this design decision, but I don't remember the gist of it.  [Rather,
I remember two possible answers and I'm having trouble remembering which
was appropriate to this particular question.]


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