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Date: Fri, 6 Mar 2009 02:27:25 -0800 (PST)
From: David Rientjes <rientjes@google.com>
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To: Peter Zijlstra <peterz@infradead.org>
cc: Ingo Molnar <mingo@elte.hu>, "David S. Miller" <davem@davemloft.net>,
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Subject: Re: [patch 2/2] lockdep: initialize lockdep debugging statistics
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On Fri, 6 Mar 2009, Peter Zijlstra wrote:

> > Peter, this is purely a matter of good software engineering practices. 
> 
> For complex types I would agree, but atomic_t is assumed to be just
> another int - just with special ops. For such things we can hold that
> memset('0') will properly initialize them to their 0 value.
> 

That's the point about good software engineering practices: atomic_t 
should not be assumed to be another int.  If its implementation were ever 
to change even for a single architecture, so would these variable 
declarations.

> > I assume you wouldn't object to removing all such cases in the kernel.
> > 
> >         $ grep -r "atomic_t.*= ATOMIC_INIT(0)" * | wc -l
> >         104
> 
> Only IFF all those cases are for static/global storage.

They are.

Anyway, I've already deferred to your maintainership of lockdep about not 
wanting to initialize global atomics in this part of the kernel, so while 
I disagree with it from a software engineering perspective, I think I'll 
be able to move on.