Re: [PATCH] no need to check for NULL before calling kfree() -fs/ext2/

[Horst von Brand <vonbrand@inf.utfsm.cl>]

Dave Jones <davej@redhat.com> said:
> On Sun, Mar 27, 2005 at 05:12:58PM +0200, Jan Engelhardt wrote:
> 
>  > Well, kfree inlined was already mentioned but forgotten again.
>  > What if this was used:
>  > 
>  > inline static void kfree_WRAP(void *addr) {
>  >     if(likely(addr != NULL)) {
>  >         kfree_real(addr);
>  >     }
>  >     return;
>  > }
>  > 
>  > And remove the NULL-test in kfree_real()? Then we would have:

> Am I the only person who is completely fascinated by the
> effort being spent here micro-optimising something thats
> almost never in a path that needs optimising ?
> I'd be amazed if any of this masturbation showed the tiniest
> blip on a real workload, or even on a benchmark other than
> one crafted specifically to test kfree in a loop.

Right.

> That each occurance of this 'optimisation' also saves a handful
> of bytes in generated code is it's only real benefit afaics.

No. It clears up the calls to kfree() a bit too in the source. Not really
important, sure.
.
> Even then, if a functions cache performance is better off because
> we trimmed a few bytes from the tail of a function, I'd be
> completely amazed.
> 
> I guess April 1st came early this year.

Got (at) you! ;-)
-- 
Dr. Horst H. von Brand                   User #22616 counter.li.org
Departamento de Informatica                     Fono: +56 32 654431
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Casilla 110-V, Valparaiso, Chile                Fax:  +56 32 797513
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