Re: + sparc64-rename-tlb_flush_mmu.patch added to -mm tree

[Russell King <rmk@arm.linux.org.uk>]

On Tue, Jul 17, 2007 at 12:08:20PM -0700, Andrew Morton wrote:
> On Tue, 17 Jul 2007 19:18:43 +0100 Russell King <rmk@arm.linux.org.uk> wrote:
> 
> > On Tue, Jul 17, 2007 at 03:56:23PM +0200, Martin Schwidefsky wrote:
> > > On Tue, 2007-07-17 at 01:03 -0700, Andrew Morton wrote:
> > > > OK, I don't understand how this patch works - from a quick glance it
> > > > appears to be forgetting to flush stuff altogether on arm and arm26 at
> > > > least and I see no sign that Russell, Tony and Ian have even seen it.
> > > 
> > > Added linux-arch so that affected arch-maintainers can comment.
> > 
> > Having a little more information about Andrew's concern would be nice.
> > Under what circumstances do you think we're forgetting to flush stuff?
> > 
> 
> "quick glance".  ARM's tlb_flush_mmu() becomes a no-op and I though that
> some real tlb_finish_mmu() got replaced by that.  But I didn't look very
> closely.

I don't think ARM will have a problem with this change.

In the fullmm case, tlb_finish_mmu() will flush the entire mm, so
missing out the flush for each chunk is itself a worthwhile optimisation.

In the !fullmm case, tlb_finish_mmu() does nothing as far as flushing
is concerned, and in any case does nothing with it's start and end
variables.

So I think this patch suits us just fine.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of: