Re: SL*B: drop kmem cache argument from constructor

From: Nick Piggin
Date: Mon Jul 14 2008 - 00:48:42 EST


On Saturday 12 July 2008 07:40, Jon Tollefson wrote:
> Andrew Morton wrote:

> > btw, Nick, what's with that dopey
> >
> > huge_pgtable_cache(psize) = kmem_cache_create(...
> >
> > trick? The result of a function call is not an lvalue, and writing a
> > macro which pretends to be a function and then using it in some manner
> > in which a function cannot be used is seven ways silly :(

I agree it isn't nice.


> That silliness came from me.
> It came from my simplistic translation of the existing code to handle
> multiple huge page sizes. I would agree it would be easier to read and
> more straight forward to just have the indexed array directly on the
> left side instead of a macro. I can send out a patch that makes that
> change if desired.
> Something such as
>
> +#define HUGE_PGTABLE_INDEX(psize) (HUGEPTE_CACHE_NUM + psize - 1)
>
> -huge_pgtable_cache(psize) = kmem_cache_create(...
> +pgtable_cache[HUGE_PGTABLE_INDEX(psize)] = kmem_cache_create(...
>
>
> or if there is a more accepted way of handling this situation I can
> amend it differently.

If it is a once off initialization (which it is), that's probably fine
like that. Otherwise, the convention is to have a set_huge_pgtable_cache
function as well. But whatever you prefer. Yes if you can send a patch,
that would be good, thanks.
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