Re: ~500 megs cached yet 2.6.5 goes into swap hell

Benjamin Herrenschmidt
2004-04-29T06:33:12Z

On Thu, 2004-04-29 at 16:22, Andrew Morton wrote:
> Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> >
> >
> > > The really strange thing is that the behaviour seems to get worse the
> > > more RAM you have. I haven't noticed any problem at all on my laptop
> > > with 768MB, only on the G5, which has 2.5GB. (The laptop is still on
> > > 2.6.2-rc3 though, so I will try a newer kernel on it.)
> >
> > Your G5 also has a 2Gb IO hole in the middle of zone DMA, it's possible
> > that the accounting doesn't work properly.
>
> heh. It should have zone->spanned_pages - zone->present_pages = 2G.

That should be fine, I'll check later, I can't reboot mine right now.

I'm initializing the zone with free_area_init_node() and I _am_ passing
the hole size. Paul, also check if you have NUMA enabled in .config, it changes
the way zones are initialized, I may have gotten that case wrong.

Ben.