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From: Jamie Lokier <jamie@shareable.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Anton Blanchard <anton@samba.org>,
	akpm@linux-foundation.org, willy@linux.intel.com,
	benh@kernel.crashing.org, paulus@samba.org,
	linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2]: atomic_t: Remove volatile from atomic_t definition
Date: Mon, 17 May 2010 21:13:39 +0100	[thread overview]
Message-ID: <20100517201339.GJ20356@shareable.org> (raw)
In-Reply-To: <alpine.LFD.2.00.1005170800100.4195@i5.linux-foundation.org>

Linus Torvalds wrote:
> 
> 
> On Mon, 17 May 2010, Anton Blanchard wrote:
> > 
> > It turns out this bad code is a result of us defining atomic_t as a
> > volatile int.
> 
> Heh. Ok, as you point out in the commit message, I obviously agree with 
> this patch. "volatile" on data is evil, with the possible exception of 
> "jiffies" type things.

I wonder if

   extern unsigned long __nv_jiffies;
   #define jiffies (*(volatile unsigned long *)*__nv_jiffies)

would improve any code in the same way as this atomic_t change.

-- Jamie

  reply	other threads:[~2010-05-17 20:13 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-17  4:33 [PATCH 1/2]: atomic_t: Cast to volatile when accessing atomic variables Anton Blanchard
2010-05-17  4:34 ` [PATCH 2/2]: atomic_t: Remove volatile from atomic_t definition Anton Blanchard
2010-05-17  8:58   ` Heiko Carstens
2010-05-17 15:01   ` Linus Torvalds
2010-05-17 20:13     ` Jamie Lokier [this message]
2010-05-17 20:20       ` Linus Torvalds
2010-05-19 13:03     ` Nick Piggin
2010-05-19 14:55       ` Linus Torvalds
2010-05-19 15:01       ` Paul E. McKenney
2010-05-19 19:54         ` David Miller
2010-05-19 22:50           ` Paul E. McKenney
2010-05-21  5:27             ` Nick Piggin
2010-05-21  5:54               ` David Miller
2010-05-21  6:06                 ` Nick Piggin
2010-05-21  6:10                   ` David Miller
2010-05-21  6:44                     ` Eric Dumazet

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