Re: [PATCH 3/3] x86: OLPC: speed up device tree creation during boot(v2)

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxx> wrote:

> > However, I have to vehemently object to putting them in a wider scope
> > than is otherwise necessary.  I agree that static variables should be
> > used sparsely if at all (there really are vary few uses of them that are
> > valid), but putting them in a larger scope screams "I'm used in more
> > than one function", and that is *not* a good thing.
> 
> That's why we sometimes use the (imperfect) compromise to put them in front of 
> that function, not at the top of the file.
> 
> Look at the general balance of hardship: very little harm is done (it's not a big 
> deal if a variable is only used in a single function) but having it with local 
> variables can be _really_ harmful - for example i overlooked them when i reviewed 
> this patch. I dont like important details obscured - i like them to be apparent. 
> Again, this is something that some people can parse immediately on the visual 
> level - me and many others cannot.

As an addendum, beyond my own bad experience with them, see below a recent upstream 
fix that shows the kinds of problems that overlooked function scope statics can 
cause.

	Ingo

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