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Date: Fri, 21 Apr 2006 21:22:17 +0200
From: Adrian Bunk <bunk@stusta.de>
To: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: Dmitry Fedorov <dm.fedorov@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: kfree(NULL)
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On Fri, Apr 21, 2006 at 05:07:45PM +0200, Jan Engelhardt wrote:
> >> Maybe kfree should really be a wrapper around __kfree which does the real
> >> work.  Then kfree could be a inlined function or a #define that does the NULL
> >> pointer check.
> >
> >NULL pointer check in kfree saves lot of small code fragments in callers.
> >It is one of many reasons why kfree does it.
> >Making kfree inline wrapper eliminates this save.
> 
> How about
> 
> slab.h:
> #ifndef CONFIG_OPTIMIZING_FOR_SIZE
> static inline void kfree(const void *p) {
>     if(p != NULL)
>         __kfree(p);
> }
> #else
> extern void kfree(const void *);
> #endif
> 
> slab.c:
> #ifdef CONFIG_OPTIMIZING_FOR_SIZE
> void kfree(const void *p) {
>     if(p != NUILL)
>         _kfree(p);
> }
> #endif
> 
> That way, you get your time saving with -O2 and your space saving with -Os.


What makes you confident that the static inline version gives a time 
saving?


> Jan Engelhardt

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed