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Date: Tue, 29 May 2007 20:14:50 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Christoph Hellwig <hch@infradead.org>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>, linux-kernel@vger.kernel.org,
       Bill Huey <billh@gnuppy.monkey.org>, Jason Baron <jbaron@redhat.com>,
       Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH 2/5] lockdep: sanitise CONFIG_PROVE_LOCKING
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On Tue, 29 May 2007 16:16:17 +0200 Ingo Molnar <mingo@elte.hu> wrote:

> 
> * Christoph Hellwig <hch@infradead.org> wrote:
> 
> > On Tue, May 29, 2007 at 02:52:50PM +0200, Peter Zijlstra wrote:
> > > Ensure that all of the lock dependency tracking code is under
> > > CONFIG_PROVE_LOCKING. This allows us to use the held lock tracking code
> > > for other purposes.
> > 
> > There's an awfull lot of ifdefs introduced in this patch, I wonder 
> > whether it might be better to split up lockdep.c at those boundaries.
> 
> it adds 6 new #ifdefs. There's 35 #ifdefs in page_alloc.c, 44 in 
> sysctl.c and 64 in sched.c. I'd not call it 'an awful lot', although 
> certainly it could be reduced. Splitting lockdep.c up would uglify it 
> well beyond the impact of the 6 #ifdefs, given the amount of glue 
> needed.
> 

I'm not sure that we need to split lockdep.c, but it's a bit disappointing
that the patch didn't (couldn't?) move CONFIG_PROVE_LOCKING-only code and
data close together so that it can all fall within a single (or at least
fewer) ifdefs.

(Who came up with the (mis)name CONFIG_PROVE_LOCKING, btw?  Should have
been CONFIG_MIGHT_DISPROVE_LOCKING).