Re: 2.6.23 boot failures on x86-64.

Andi Kleen
2007-10-29T19:56:19Z

On Monday 29 October 2007 20:43:11 Dave Jones wrote:
> On Mon, Oct 29, 2007 at 08:03:09PM +0100, Andi Kleen wrote:
>
> > > > It's probably the usual "nobody tests sparsemem at all" issue.
> > >
> > > We've been using SPARSEMEM in Fedora for a *long* time.
> > > So long in fact, I forget why we moved away from DISCONTIGMEM, so there's
> > > a significant number of users using that configuration for some time.
> >
> > Supposedly you wanted a slower kernel that needs more memory?
> >
> > Ok I wasn't aware of that. I tended to get sparsemem reports usually
> > at least 1-2 releases after the fact, so it looked like it was undertested.
>
> Looking at cvs history, I can't figure out what the reasoning was,
> but every Fedora (and RHEL5) kernel since 2006/07/05 has been that way.
>
> Curious how no-one noticed either of the side-effects you mention.

It's a few percent on a few benchmarks iirc. vmemmap (now in .24) was supposed
to address that.

-Andi