Re: vDSO vs. mm : problems with ppc vdso

Benjamin Herrenschmidt
2006-03-01T02:26:59Z

On Wed, 2006-03-01 at 13:24 +1100, Nick Piggin wrote:
> Hugh Dickins wrote:
> > On Tue, 28 Feb 2006, Nick Piggin wrote:
> >
> >>You should be OK. VM_RESERVED itself is something of an anachronism
> >>these days. If you're not getting your page from the page allocator
> >>then you'll want to make sure each of their count, and mapcount is
> >>reset before allowing them to be mapped.
> >
> >
> > Yes, it's fine that VM_RESERVED isn't set on it.
> > But I don't understand your remarks about count and mapcount at all:
> > perhaps you meant to say something else?
> >
>
> Yes, count should be elevated.
>
> mapcount should be reset, to avoid the bug in page_remove_rmap.

Can you be more explicit ?

Cheers,
Ben.