Re: Increase page fault rate by prezeroing V1 [1/3]: Introduce __GFP_ZERO

[Andi Kleen <ak@suse.de>]

Christoph Lameter <clameter@sgi.com> writes:
> @@ -0,0 +1,52 @@
> +/*
> + * Zero a page.
> + * rdi	page
> + */
> +	.globl zero_page
> +	.p2align 4
> +zero_page:
> +	xorl   %eax,%eax
> +	movl   $4096/64,%ecx
> +	shl	%ecx, %esi

Surely must be shl %esi,%ecx


> +zero_page_c:
> +	movl $4096/8,%ecx
> +	shl	%ecx, %esi

Same.

Haven't tested.

But for the one instruction it seems overkill to me to have a new
function. How about you just extend clear_page with the order argument?

BTW I think Andrea has been playing with prezeroing on x86 and
he found no benefit at all. So it's doubtful it makes any sense
on x86/x86-64.

-Andi