Re: [PATCH] (1/2) reverse mapping VM for 2.5.23 (rmap-13b)

Rik van Riel
2002-06-24T15:30:45Z

On Wed, 19 Jun 2002, Ingo Molnar wrote:
> On Wed, 19 Jun 2002, Rik van Riel wrote:
>
> > I am encouraged by Craig's test results, which show that
> > rmap did a LOT less swapin IO and rmap with page aging even
> > less. The fact that it did too much swapout IO means one
> > part of the system needs tuning but doesn't say much about
> > the thing as a whole.
>
> btw., isnt there a fair chance that by 'fixing' the aging+rmap code to
> swap out less, you'll ultimately swap in more? [because the extra swappout
> likely ended up freeing up RAM as well, which in turn decreases the amount
> of trashing.]

Possibly, but I expect the 'extra' swapouts to be caused
by page_launder writing out too many pages at once and not
just the ones it wants to free.

Cleaning pages and freeing them are separate operations,
what is missing is a mechanism to clean enoughh pages but
not all inactive pages at once ;)

regards,

Rik
--
Bravely reimplemented by the knights who say "NIH".

http://www.surriel.com/ http://distro.conectiva.com/