Re: memcpy and prefetch

[Atsushi Nemoto <anemo@mba.ocn.ne.jp>]

On Wed, 28 Jan 2009 10:37:53 +0000, Ralf Baechle <ralf@linux-mips.org> wrote:
> > The Cavium OCTEON port overrides the default memcpy and does use  
> > prefetch.  It was recently merged (2.6.29-rc2).  Look at octeon-memcpy.S
> >
> > I have thought that memcpy could be generated by mm/page.c as copy_page  
> > and clear_page are.
> 
> No, these two only generate copy_page and clear_page.  I and Thiemo were
> considering to extend this to a full memcopy however.

BTW, this code in memcpy.S (and memcpy-atomic.S) looks weird.

#if !defined(CONFIG_DMA_COHERENT) || !defined(CONFIG_DMA_IP27)
#undef CONFIG_CPU_HAS_PREFETCH
#endif
#ifdef CONFIG_MIPS_MALTA
#undef CONFIG_CPU_HAS_PREFETCH
#endif

Are there any configuration which do not undef CONFIG_CPU_HAS_PREFETCH ? ;-)

---
Atsushi Nemoto