[PATCH 2/4] powerpc: Fix 32 bits mm operations when not using BATs

[Benjamin Herrenschmidt]

On Thu, 2007-03-22 at 12:55 +0100, Segher Boessenkool wrote:
> > +	 * If the hash table bucket is full of kernel text entries, we'll
> > +	 * lockup here but that shouldn't happen
> 
> On 32-bit we have room for one HPTE per real page -- assuming
> the kernel text is fully enclosed inside one power-of-two
> size and aligned range of address space (i.e. always ;-) ),
> a lockup here _cannot_ happen.  It doesn't get tight until you
> start using all of memory as kernel text.

I know, which is why "shouldn't" is a good enough choice of word :-)

> So replace this comment with something like "the HTAB is
> sized such that no PTEG can overflow from kernel text alone"?
> It sounds a lot less hand-wavy than "but this shouldn't happen".

Patch welcome :-)

Ben.