Re: boot fail with large RAM

[Frank van der Linden <fvdl%netbsd.org@localhost>]

Manuel Bouyer wrote:
> On Wed, Nov 18, 2009 at 08:23:22PM +0100, Manuel Bouyer wrote:
>   
> > [...]
> > I also noticed that amd64 has only 2 free lists, one for the low 16MB
> > memory and one for anything else. Would it help to move to a third
> > free list; one for low 16MB, a second for the low 4GB and a third one for
> > anything else ? uvm(9) doens't say much about free lists ...
> >     
>
> I tried it; it helps a lot (see attached dmesg). The system can boot,
> and devices seems to be working fine. I also tested it on a desktop with
> 8GB ram, and another one with 2GB.
> I think this patch can also help systems which don't have troubles at
> boot time but could end up with bus_dma(9) allocation failures at
> run time. So unless someone objects I'm going to commit the attached
> patch in the next few days, and request a pullup to netbsd-5.
>
>   
Yep, your patch is the right thing to do. I remember considering this 
when I first did the amd64 port, but somehow it ended up on the 
backburner and I forgot about it.

The thing that is eating up all your low memory is probably VM page 
structures. With 128G, there are some 32M of them, so that counts for a 
lot (probably about 2.5G total).

- Frank