Re: Prezeroing V3 [2/4]: Extension of clear_page to take an orderparameter

[Christoph Lameter]

On Thu, 6 Jan 2005, Andi Kleen wrote:

> Christoph Lameter <clameter@xxxxxxx> writes:
>
> > Here is an updated version that is independent of the first patch and
> > contains all the necessary modifications to make clear_page take a second
> > parameter.
>
> I still think the clear_page order addition is completely pointless,
> because for > order 0 you probably want a cache bypassing store
> in a separate function.

I would think that having clear_page avoid loading cache
lines from memory should be general improvement.

Bypassing the cache may be beneficial for clear_page in general but I
would like to test that first.

If this is not a win then it may be better to implement the bypassing the
cache through a zero driver.

> Removing it would also make the patch much less intrusive.

Right. I also thought about that. I will likely offer the clear_page patch
as an optional component in V4. Being able to specify an order with
clear_page also helps in other situations like clearing huge pages.

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