Re: [PATCH 14/15] mm: Drop unlikely before IS_ERR(_OR_NULL)

[Viresh Kumar]

On 31-07-15, 11:00, Joe Perches wrote:
> On Fri, 2015-07-31 at 16:36 +0530, Viresh Kumar wrote:
> > On 31-07-15, 03:28, Joe Perches wrote:
> > > If it's all fixed, then it's unlikely to be needed in checkpatch.
> > 
> > I thought checkpatch is more about not committing new mistakes, rather than
> > finding them in old code.
> 
> True, but checkpatch is more about style than substance.
> 
> There are a lot of things that _could_ be added to the script
> but don't have to be because of relative rarity.
> 
> The unanswered fundamental though is whether the unlikely use
> in #define IS_ERR_VALUE is useful.
> 
> include/linux/err.h:21:#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
> 
> How often does using unlikely here make the code smaller/faster
> with more recent compilers than gcc 3.4?  Or even using gcc 3.4.

No idea :)


-- 
viresh
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