From: Peter Zijlstra <peterz@infradead.org>
To: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: jmerkey@wolfmountaingroup.com, linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Nick Piggin <nickpiggin@yahoo.com.au>,
Paul E McKenney <paulmck@linux.vnet.ibm.com>,
David Howells <dhowells@redhat.com>
Subject: Re: [ANNOUNCE] mdb: Merkey's Linux Kernel Debugger 2.6.27-rc4 released
Date: Thu, 21 Aug 2008 13:02:48 +0200 [thread overview]
Message-ID: <1219316568.8651.107.camel@twins> (raw)
In-Reply-To: <48AD4A0B.8020805@s5r6.in-berlin.de>
On Thu, 2008-08-21 at 12:57 +0200, Stefan Richter wrote:
> Peter Zijlstra wrote:
> > On Wed, 2008-08-20 at 20:50 -0600, jmerkey@wolfmountaingroup.com wrote:
> >
> >> volatiles left in the code due to the previously stated
> >> (and still present) severe breakage of the GNU compiler with SMP
> >> shared data. most of the barrier() functions are just plain broken
> >> and do not result in proper compiler behavior in this tree.
> >
> > Can you provide explicit detail?
> >
> > By using barrier() the compiler should clobber all its memory and
> > registers therefore forcing a write/reload of the variable.
>
> I hope Jeff didn't try mere barrier()s only. smp_wmb() and smp_rmb()
> are the more relevant barrier variants for mdb, from what I remember
> when I last looked at it.
Sure, but volatile isn't a replacement for memory barriers.
next prev parent reply other threads:[~2008-08-21 11:03 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-21 2:50 [ANNOUNCE] mdb: Merkey's Linux Kernel Debugger 2.6.27-rc4 released jmerkey
2008-08-21 10:07 ` Peter Zijlstra
2008-08-21 10:57 ` Stefan Richter
2008-08-21 11:02 ` Peter Zijlstra [this message]
2008-08-21 11:47 ` Paul E. McKenney
2008-08-21 12:03 ` Peter Zijlstra
2008-08-21 14:53 ` Paul E. McKenney
2008-08-21 14:58 ` jmerkey
2008-08-21 12:05 ` Stefan Richter
2008-08-21 12:26 ` jmerkey
[not found] ` <43593.166.70.238.46.1219321595.squirrel@webmail.wolfmountaingroup.com >
2008-08-21 12:35 ` jmerkey
2008-08-21 13:37 ` Nick Piggin
2008-08-21 14:09 ` Stefan Richter
2008-08-22 1:40 ` Nick Piggin
2008-08-22 6:32 ` Stefan Richter
2008-08-22 11:54 ` jmerkey
2008-08-22 12:36 ` Stefan Richter
2008-08-21 14:09 ` Peter Zijlstra
2008-08-21 14:30 ` Paul E. McKenney
2008-08-21 14:14 ` jmerkey
2008-08-21 14:48 ` Peter Zijlstra
2008-08-21 16:21 ` Avi Kivity
2008-08-21 21:06 ` Jeremy Fitzhardinge
2008-08-21 21:18 ` Linus Torvalds
2008-08-21 21:21 ` Jeremy Fitzhardinge
2008-08-24 4:25 ` jmerkey
2008-08-26 8:26 ` Andi Kleen
2008-08-27 1:49 ` jmerkey
2008-08-22 1:37 ` Nick Piggin
2008-08-21 14:02 ` Stefan Richter
2008-08-21 14:08 ` jmerkey
2008-08-21 15:22 ` Stefan Richter
2008-08-21 15:02 ` jmerkey
2008-08-21 15:57 ` Linus Torvalds
2008-08-21 16:18 ` Linus Torvalds
2008-08-21 16:48 ` Paul E. McKenney
2008-09-24 0:01 ` Paul E. McKenney
2008-08-21 16:43 ` Paul E. McKenney
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