Re: SW TLB MMU rework and SMP issues (pte read/write)

On Jul 16, 2008, at 4:41 PM, Benjamin Herrenschmidt wrote:

On Wed, 2008-07-16 at 15:57 -0500, Kumar Gala wrote:

quoted

This makes sense.  I think we need to order the stores in set_pte_at
regardless of CONFIG_SMP.

Nah, that shouldn't be necessary.

Yeah I finally came to that realization.

quoted

Also, I think we should change pte_clear to
use pte_update() so we only clear the low-order flag bits.  Patch  
will
be sent shortly for review.

Well... at one point at least we did rely on a PTE page with all PTEs
cleared to be blank. It don't know if that's still the case, I need to
look.

Doesn't look like we do anything special, we just call free_pages or  
__free_pages in arch/powerpc/mm/pgtable_32.c.

- k