Problems with AMD64 and 8 GB RAM?

[Peter Wemm]

On Wednesday 30 March 2005 03:09 pm, Greg 'groggy' Lehey wrote:
> On Wednesday, 30 March 2005 at 16:04:44 -0700, Scott Long wrote:
> > Greg 'groggy' Lehey wrote:
> >> On Wednesday, 30 March 2005 at 15:30:37 -0700, Scott Long wrote:
> >>> Greg 'groggy' Lehey wrote:
> >>>> I've recently acquired an AMD64 box ...
> >>>>
> >>>> What's unstable?  ... The amd64 5.4-PRERELEASE kernel just
> >>>> hangs/freezes.
> >>>
> >>> 5.3-RELEASE has a lot of problems with >4GB due to busdma issues.
> >>> Those should no longer be an issue in RELENG_5, including
> >>> 5.4-PRE.
> >>
> >> They appear to be.
> >
> > I don't understand what you mean here.
>
> As I said above (and trimmed for convenience), this problem occurs on
> 5.4-PRERELEASE as of yesterday morning.  The dmesg shows that too.
>
> >> As I described, it doesn't appear to be the drivers.
> >
> > I don't see how you proved or disproved this.
>
> Shall I resend the original message?  It seems independent of any
> particular driver.  That's not proof, of course, but I didn't claim
> it was.

Greg:  The busdma problems from 5.3-RELEASE are fixed.  That doesn't 
mean that there are no *other* problems.  Scott is saying "the old 
busdma bug shouldn't be affecting 5.4-PRE", and he's correct.

Most likely, something else is happening, eg: you're running out of KVM 
or something silly like that.  I know we're right on the brink at 8GB.   
The layout of the devices may be just enough to tip it over the edge.
-- 
Peter Wemm - peter at wemm.org; peter at FreeBSD.org; peter at yahoo-inc.com
"All of this is for nothing if we don't go to the stars" - JMS/B5