Re: [patch 3/3] arch_rebalance_pgtables call

Martin Schwidefsky
2007-11-15T17:13:21Z

On Thu, 2007-11-15 at 09:07 +1100, Benjamin Herrenschmidt wrote:
> On Wed, 2007-11-14 at 12:49 +0100, Martin Schwidefsky wrote:
> >
> > They all either have an arch override, call get_unmapped_area again or
> > are not relevant. So it should be possible to do the upgrade in
> > arch_get_unmapped_area. I still have my doubts though, all future uses
> > of the get_unmapped_area pointer have to be checked and I feel it is
> > easier to understand to do the upgrade / rebalance of the page table
> > at
> > the end of get_unmapped_area where every caller of mmap is guaranteed
> > to
> > pass through.
>
> Well, if something does what you are worried about, then it would be
> broken on powerpc as well (among others). We have various constraints on
> the address space layout that must be handled by our arch g_u_a (or our
> hugetlb one).

Ok, I rearranged the dynamic page tables code (and fixed the bug that 31
bit processes had a 3 level page table instead of 2). It is working fine
with s390 specific versions of arch_get_unmapped_area and
arch_get_unmapped_area_topdown which do the page table upgrade.

Which means we can drop the arch_rebalance_pgtables-call.patch from -mm
again.

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.