Re: [113/197] x86, cacheinfo: Calculate L3 indices

[Borislav Petkov]

From: Jiri Kosina <jkosina@xxxxxxx>
Date: Wed, May 05, 2010 at 05:33:45PM -0400

> Yeah, you are right, returning -1 is bogus as well.
> 
> The point is though, that we really should be checking for return value of 
> node_to_k8_nb_misc() as it can legitimately return NULL, can't it? (and 
> other places, such as show_cache_disable() and store_cache_disable(), are 
> checking for this being NULL properly).

Well, I don't like sprinkling NULL ptr checks all over the place - this
makes the code unreadable and means that there's something wrong with
its design in the first place.

Therefore, it is better IMO to verify whether the K8_NB thing is
initialized properly and exit early if not. And this is what the two
patches I'm suggesting try to accomplish:

1. Call into K8_NB on AMD unconditionally so that we have those
initialized (we'll be needing them more in the future, I guess)

2. Check in the L3 cache code whether K8_NB has initted properly and
bail out if not.

With this, no need for NULL ptr checks anywhere and you got
better/smaller/more readable code with the proper assumptions in place.

Thanks.

-- 
Regards/Gruss,
Boris.

--
Advanced Micro Devices, Inc.
Operating Systems Research Center

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