Re: replace "memset(...,0,PAGE_SIZE)" calls with "clear_page()"?

From: Arjan van de Ven
Date: Sun Dec 31 2006 - 08:46:03 EST

On Sun, 2006-12-31 at 14:39 +0100, Folkert van Heusden wrote:
> > > i don't see how that can be true, given that most of the definitions
> > > of the clear_page() macro are simply invocations of memset(). see for
> > > yourself:
> > *MOST*. Not all.
> > For example an SSE version will at least assume 16 byte alignment, etc
> > etc.
> What about an if (adress & 15) { memset } else { sse stuff }
> or is that too obvious? :-)

it's only one example. clear_page() working only on a full page is a
nice restriction that allows the implementation to be optimized (again
the x86 hardware that had a hardware page zeroer comes to mind, the hw
is only 4 years old or so... and future hw may have it again)

clear_page() is more restricted than memset(). And that's good, it
allows for a more focused implementation. Otherwise there'd be no reason
to HAVE a clear_page(), if it just was a memset wrapper entirely.

if you want to mail me at work (you don't), use arjan (at)
Test the interaction between Linux and your BIOS via

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at