Re: [PATCH 2/2] page table iterators

[Hugh Dickins <hugh@veritas.com>]

On Thu, 24 Feb 2005, Nick Piggin wrote:
> Hugh Dickins wrote:
> 
> > I'm inlining pmd and pud levels, but not pte and pgd levels.
> 
> OK - that's probably sufficient for debugging. There is only so
> much that can go wrong in the middle levels... 

Yes, that was my thinking.

> how does it look
> performance wise? (I can give it a test when it gets split out)

Yesterday shattered in various directions, I hope to try today.

> > One point worth making, I do believe throughout that whatever the
> > address layout, "end" cannot be 0 - BUG_ON(addr >= end) assures.

Of course, that does allow some simplifications in your for_each
macros; but it still looked like my p??_limits were better for
shortest codepath, and close to yours for codesize.

> OK after sleeping on it, I'm warming to your way.
> 
> I don't think it makes something like David's modifications any
> easier, but mine didn't go a long way to that end either. And
> being a more incremental approach gives us more room to move in
> future (for example, maybe toward something that really *will*
> accommodate the bitmap walking code nicely).

I'll take a quick look at David's today.
Just so long as we don't make them harder.

> So I'd be pretty happy for you to queue this up with Andrew for
> 2.6.12. Anyone else?

Oh, okay, thanks.  You weren't very happy with p??_limit(addr, end),
and good naming is important to me.  I didn't care for your tentative
p??_span or p??_span_end.  Would p??_end be better?  p??_enda would
be fun for one of them...

Hugh