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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>
Subject: Re: [PATCH] checkpatch: Make the memory barrier test noisier
Date: Fri, 27 Sep 2013 07:34:55 -0700	[thread overview]
Message-ID: <1380292495.17366.106.camel@joe-AO722> (raw)
In-Reply-To: <20130927142605.GC15690@laptop.programming.kicks-ass.net>

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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  reply	other threads:[~2013-09-27 14:35 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1380144003.git.tim.c.chen@linux.intel.com>
2013-09-25 22:10 ` [PATCH v6 0/6] rwsem: performance optimizations Tim Chen
2013-09-25 22:10 ` [PATCH v6 1/6] rwsem: check the lock before cpmxchg in down_write_trylock Tim Chen
2013-09-25 22:10 ` [PATCH v6 2/6] rwsem: remove 'out' label in do_wake Tim Chen
2013-09-25 22:10 ` [PATCH v6 3/6] rwsem: remove try_reader_grant label do_wake Tim Chen
2013-09-25 22:10 ` [PATCH v6 4/6] rwsem/wake: check lock before do atomic update Tim Chen
2013-09-25 22:10 ` [PATCH v6 5/6] MCS Lock: Restructure the MCS lock defines and locking code into its own file Tim Chen
2013-09-26  6:46   ` Ingo Molnar
2013-09-26  8:40     ` Peter Zijlstra
2013-09-26  9:37       ` Ingo Molnar
2013-09-26 18:18       ` Tim Chen
2013-09-26 19:27   ` Jason Low
2013-09-26 20:06     ` Davidlohr Bueso
2013-09-26 20:23       ` Jason Low
2013-09-26 20:40         ` Davidlohr Bueso
2013-09-26 21:09           ` Jason Low
2013-09-26 21:41             ` Tim Chen
2013-09-26 22:42               ` Jason Low
2013-09-26 22:57                 ` Tim Chen
2013-09-27  6:02                   ` Ingo Molnar
2013-09-27  6:26                     ` Jason Low
2013-09-27 11:23                     ` Peter Zijlstra
2013-09-27 13:44                       ` Joe Perches
2013-09-27 13:48                         ` Peter Zijlstra
2013-09-27 14:05                           ` Joe Perches
2013-09-27 14:18                             ` Peter Zijlstra
2013-09-27 14:14                           ` [PATCH] checkpatch: Make the memory barrier test noisier Joe Perches
2013-09-27 14:26                             ` Peter Zijlstra
2013-09-27 14:34                               ` Joe Perches [this message]
2013-09-27 14:50                                 ` Peter Zijlstra
2013-09-27 15:17                                   ` Paul E. McKenney
2013-09-27 15:34                                     ` Peter Zijlstra
2013-09-27 16:04                                       ` Paul E. McKenney
2013-09-27 23:40                                   ` Oliver Neukum
2013-09-28  7:54                                     ` Peter Zijlstra
2013-09-27 16:12                     ` [PATCH v6 5/6] MCS Lock: Restructure the MCS lock defines and locking code into its own file Jason Low
2013-09-27 16:19                       ` Tim Chen
2013-10-02 19:19                 ` Waiman Long
2013-10-02 19:30                   ` Jason Low
2013-10-02 19:37                     ` Waiman Long
2013-09-26 22:22             ` Davidlohr Bueso
2013-09-27 15:29   ` Paul E. McKenney
2013-09-27 18:09     ` Tim Chen
2013-09-28  2:58       ` Waiman Long
2013-09-27 19:38     ` Tim Chen
2013-09-27 20:16       ` Jason Low
2013-09-27 20:38       ` Paul E. McKenney
2013-09-27 22:46         ` Tim Chen
2013-09-27 23:01           ` Paul E. McKenney
2013-09-27 23:54             ` Jason Low
2013-09-28  0:02               ` Davidlohr Bueso
2013-09-28  2:19               ` Paul E. McKenney
2013-09-28  4:34                 ` Jason Low
2013-09-30 15:51                   ` Waiman Long
2013-09-30 16:10                     ` Jason Low
2013-09-30 16:36                       ` Waiman Long
2013-10-01 16:48                         ` Tim Chen
2013-10-01 20:01                           ` Waiman Long
2013-10-01 21:16                             ` Tim Chen
2013-10-02  1:25                               ` Waiman Long
2013-10-02 18:43                                 ` Tim Chen
2013-10-02 19:32                                   ` Waiman Long
2013-09-30 16:28                 ` Tim Chen
2013-09-25 22:10 ` [PATCH v6 6/6] rwsem: do optimistic spinning for writer lock acquisition Tim Chen
2013-09-26  6:53   ` Ingo Molnar

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