Re: [PATCH] Implement slub fastpath in terms of freebase and freeoffset

From: Christoph Lameter
Date: Fri Feb 29 2008 - 14:57:28 EST


On Fri, 29 Feb 2008, Mathieu Desnoyers wrote:

> > Then we do not need the page->end field anymore right? I will try
> > to rediff your patch against current slab-mm and see how we can proceed
> > from there.
>
> I guess you could replace page->end with the (expensive)
> page_address(page) + 1 in new_slab.
>
> You would also have to change slab_address() to use
> page_address(page). Since this is used by check_valid_pointer, I am not
> sure it's a good idea to use this slow operation there.
>
> Or maybe you have a different alternative in mind ?

page->end was introduced to have a unique pointer for each slab. The
counter that you introduces can take over that role. So we could use a
NULL pointer again as the end of the objects? Or some constant?

I am going to revert the change that introduced page->end for 2.6.25 since
it seems that the new fastpath does not need this. It was specific to the
old fastpath.

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