Re: [PATCH 1/4] x86_64: Switch to SPARSE_VIRTUAL

Christoph Lameter
2007-04-02T22:29:06Z

On Mon, 2 Apr 2007, Dave Hansen wrote:

> On Mon, 2007-04-02 at 14:28 -0700, Christoph Lameter wrote:
> > I do not care what its called as long as it
> > covers all the bases and is not a glaring performance regresssion (like
> > SPARSEMEM so far).
>
> I honestly don't doubt that there are regressions, somewhere. Could you
> elaborate, and perhaps actually show us some numbers on this? Perhaps
> instead of adding a completely new model, we can adapt the existing ones
> somehow.

Just look at pfn_to_page and friends on ia64 and see what atrocities
sparsemem does with those if you enable it.