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From: Stefan Richter <stefanr@s5r6.in-berlin.de>
To: jmerkey@wolfmountaingroup.com
Cc: Andi Kleen <andi@firstfloor.org>,
	Jason Wessel <jason.wessel@windriver.com>,
	Nick Piggin <nickpiggin@yahoo.com.au>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Josh Boyer <jwboyer@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [ANNOUNCE] Merkey's Kernel Debugger
Date: Thu, 07 Aug 2008 19:04:32 +0200	[thread overview]
Message-ID: <489B2B20.2040205@s5r6.in-berlin.de> (raw)
In-Reply-To: <1913.69.2.248.210.1218124373.squirrel@webmail.wolfmountaingroup.com>

jmerkey@wolfmountaingroup.com wrote:
>>> Also, whoever wrote "/Documentation/volatiles_are_evil" must not have
>>> worked with the busted-ass GNU compiler that optimizes away global
>>> variables and busts SMP dependent code.  I am not going to remove the
>> The Linux way to handle this is to use gcc memory barriers.
>> mb()/barrier()/wmb()/rmb()/smp_rmb()/smp_wmb() etc.
>> Normally everything that volatile can do can be expressed by them.
[...]
>> See Documentation/memory-barriers.txt
[...]
> I'll instrument this as described in the documentation you referenced and
> remove the volatile declarations.  If this passes testing, I will repost
> with these corections.

Take care though that neither memory barriers nor volatile are what you 
want if accesses need to be atomic on whatever given data structure. 
(E.g. bitfield manipulations, counter increments, accesses to virtually 
anything that is bigger than an integer or a pointer...)
-- 
Stefan Richter
-=====-==--- =--- --===
http://arcgraph.de/sr/

  reply	other threads:[~2008-08-07 17:04 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-03 17:22 jmerkey
     [not found] ` <17494.166.70.238.46.1217784156.squirrel@webmail.wolfmountaingroup.com >
2008-08-03 19:36   ` jmerkey
2008-08-03 20:00     ` Rene Herman
2008-08-04  0:14     ` Josh Boyer
2008-08-04  2:19       ` jmerkey
2008-08-04 13:41         ` Stefan Richter
2008-08-04 14:33           ` jmerkey
2008-08-05  9:41             ` Geert Uytterhoeven
2008-08-05 15:02               ` jmerkey
2008-08-05 15:33                 ` Nick Piggin
2008-08-05 15:19                   ` jmerkey
2008-08-05 15:45                     ` Nick Piggin
2008-08-05 15:32                       ` jmerkey
2008-08-05 16:38                         ` Nick Piggin
2008-08-05 16:45                           ` jmerkey
2008-08-06 19:47                           ` Rene Herman
2008-08-05 16:04                     ` Chris Friesen
2008-08-05 16:39                       ` jmerkey
2008-08-07 20:43                         ` Daniel Barkalow
2008-08-07 21:02                           ` jmerkey
2008-08-07 21:04                             ` jmerkey
2008-08-05 17:21                     ` Paul Mundt
2008-08-05 17:10                       ` jmerkey
2008-08-06  3:08                   ` Andi Kleen
2008-08-06  5:50                     ` Nick Piggin
2008-08-07 17:45                       ` Christoph Lameter
2008-08-07 17:53                         ` jmerkey
2008-08-07 18:08                         ` Stefan Richter
2008-08-07 19:10                           ` Christoph Lameter
2008-08-07 19:47                             ` Jay Lan
2008-08-07 19:34                               ` jmerkey
2008-08-08  1:26                                 ` Vivek Goyal
2008-08-07 20:06                               ` Andi Kleen
2008-08-07 20:07                                 ` Bernhard Walle
2008-08-07 20:09                                   ` Andi Kleen
2008-08-07 20:11                                     ` Bernhard Walle
2008-08-07 22:28                                 ` Keith Owens
2008-08-08  1:15                                   ` Vivek Goyal
2008-08-08  2:29                                     ` Andi Kleen
2008-08-08 12:08                                       ` Cliff Wickman
2008-08-08 12:20                                         ` Andi Kleen
2008-08-08 13:19                                           ` jmerkey
2008-08-08 15:06                                           ` Cliff Wickman
2008-08-08 13:29                                       ` Vivek Goyal
2008-08-08 14:50                                         ` Cliff Wickman
2008-08-08 16:57                                           ` Jay Lan
2008-08-11 12:56                                           ` Vivek Goyal
2008-08-08 18:03                                         ` Andi Kleen
2008-08-11 13:02                                           ` Vivek Goyal
2008-08-11 13:11                                             ` jmerkey
2008-08-11 13:50                                               ` Andi Kleen
2008-08-11 16:16                                                 ` jmerkey
2008-08-18  9:12                                             ` Takenori Nagano
2008-08-08  8:40                         ` Nick Piggin
2008-08-06 13:11                     ` Bill Davidsen
2008-08-06 13:37                       ` Stefan Richter
2008-08-06 13:54                       ` Olivier Galibert
2008-08-06 13:45                         ` jmerkey
2008-08-06 14:16                       ` Nick Piggin
2008-08-06 17:21                     ` Jason Wessel
2008-08-06 18:57                       ` Andi Kleen
2008-08-07 12:45                         ` jmerkey
2008-08-07 15:17                           ` Peter Zijlstra
2008-08-07 16:07                           ` Andi Kleen
2008-08-07 15:52                             ` jmerkey
2008-08-07 17:04                               ` Stefan Richter [this message]
2008-08-08  0:28                           ` Stefan Richter
2008-08-11 10:36 ` jidong xiao

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