[Cbe-oss-dev] [RFC 3/3] powerpc: copy_4K_page tweaked for Cell

[Mark Nelson]

On Fri, 20 Jun 2008 07:28:50 am Arnd Bergmann wrote:
> On Thursday 19 June 2008, Mark Nelson wrote:
> >         .align  7
> > _GLOBAL(copy_4K_page)
> >         dcbt    0,r4            /* Prefetch ONE SRC cacheline */
> > 
> >         addi    r6,r3,-8        /* prepare for stdu */
> >         addi    r4,r4,-8        /* prepare for ldu */
> > 
> >         li      r10,32          /* copy 32 cache lines for a 4K page */
> >         li      r12,128+8               /* prefetch distance*/
> 
> Since you have a loop here anyway instead of the fully unrolled
> code, why not provide a copy_64K_page function as well, jumping in
> here?

That is a good idea. What effect will that have on how the code
patching will work?

> 
> The inline 64k copy_page function otherwise just adds code size,
> as well as being a tiny bit slower. It may even be good to
> have an out-of-line copy_64K_page for the regular code, just
> calling copy_4K_page repeatedly.

Doing that sounds like it'll make the code patching easier.

Thanks!

Mark