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Date: Wed, 10 Apr 2013 12:31:44 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Waiman Long <Waiman.Long@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
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        "Chandramouleeswaran, Aswin" <aswin@hp.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Norton, Scott J" <scott.norton@hp.com>,
        Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH RFC 1/3] mutex: Make more scalable by doing less atomic
 operations
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* Waiman Long <Waiman.Long@hp.com> wrote:

> > That said, the MUTEX_SHOULD_XCHG_COUNT macro should die. Why shouldn't all 
> > architectures just consider negative counts to be locked? It doesn't matter 
> > that some might only ever see -1.
> 
> I think so too. However, I don't have the machines to test out other 
> architectures. The MUTEX_SHOULD_XCHG_COUNT is just a safety measure to make sure 
> that my code won't screw up the kernel in other architectures. Once it is 
> confirmed that a negative count other than -1 is fine for all the other 
> architectures, the macro can certainly go.

I'd suggest to just remove it in an additional patch, Cc:-ing 
linux-arch@vger.kernel.org. The change is very likely to be fine, if not then it's 
easy to revert it.

Thanks,

	Ingo