Message-ID: <1380292495.17366.106.camel@joe-AO722>
Subject: Re: [PATCH] checkpatch: Make the memory barrier test noisier
From: Joe Perches <joe@perches.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>, Tim Chen <tim.c.chen@linux.intel.com>,
        Jason Low <jason.low2@hp.com>, Davidlohr Bueso <davidlohr@hp.com>,
        Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@linux-foundation.org>,
        Andrea Arcangeli <aarcange@redhat.com>, Alex Shi <alex.shi@linaro.org>,
        Andi Kleen <andi@firstfloor.org>,
        Michel Lespinasse <walken@google.com>,
        Davidlohr Bueso <davidlohr.bueso@hp.com>,
        Matthew R Wilcox <matthew.r.wilcox@intel.com>,
        Dave Hansen <dave.hansen@intel.com>, Rik van Riel <riel@redhat.com>,
        Peter Hurley <peter@hurleysoftware.com>, linux-kernel@vger.kernel.org,
        linux-mm <linux-mm@kvack.org>
Date: Fri, 27 Sep 2013 07:34:55 -0700
In-Reply-To: <20130927142605.GC15690@laptop.programming.kicks-ass.net>
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On Fri, 2013-09-27 at 16:26 +0200, Peter Zijlstra wrote:
> On Fri, Sep 27, 2013 at 07:14:17AM -0700, Joe Perches wrote:
> > Peter Zijlstra prefers that comments be required near uses
> > of memory barriers.
> > 
> > Change the message level for memory barrier uses from a
> > --strict test only to a normal WARN so it's always emitted.
> > 
> > This might produce false positives around insertions of
> > memory barriers when a comment is outside the patch context
> > block.
> 
> One would argue that in that case they're too far away in any case :-)
> 
> > And checkpatch is still stupid, it only looks for existence
> > of any comment, not at the comment content.
> 
> Could we try and alleviate this by giving a slightly more verbose
> warning?

> Maybe something like:
> 
>  memory barrier without comment; please refer to the pairing barrier and
>  describe the ordering requirements.

That would make it seem as if all barriers are SMP no?

Maybe just refer to Documentation/memory-barriers.txt
and/or say something like "please document appropriately"


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