From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Peter Hurley <peter@hurleysoftware.com>,
Marc Gauthier <marc@cadence.com>,
Michael Cree <mcree@orcon.net.nz>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
David Laight <David.Laight@ACULAB.COM>,
Jakub Jelinek <jakub@redhat.com>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
Tony Luck <tony.luck@intel.com>,
"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
Oleg Nesterov <oleg@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Paul Mackerras <paulus@samba.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
Miroslav Franc <mfranc@redhat.com>,
Richard Henderson <rth@twiddle.net>,
"linux-alpha@vger.kernel.org" <linux-alpha@vger.kernel.org>
Subject: Re: bit fields && data tearing
Date: Fri, 5 Sep 2014 14:05:43 -0700 [thread overview]
Message-ID: <20140905210543.GC5001@linux.vnet.ibm.com> (raw)
In-Reply-To: <alpine.DEB.2.10.1409052247460.5472@nanos>
On Fri, Sep 05, 2014 at 10:48:34PM +0200, Thomas Gleixner wrote:
> On Fri, 5 Sep 2014, Paul E. McKenney wrote:
> > On Fri, Sep 05, 2014 at 01:34:52PM -0700, H. Peter Anvin wrote:
> > > On 09/05/2014 01:14 PM, Peter Hurley wrote:
> > > >
> > > > Here's how I read the two statements.
> > > >
> > > > First, the commit message:
> > > >
> > > > "It [this commit] documents that CPUs [supported by the Linux kernel]
> > > > _must provide_ atomic one-byte and two-byte naturally aligned loads and stores."
> > > >
> > > > Second, in the body of the document:
> > > >
> > > > "The Linux kernel no longer supports pre-EV56 Alpha CPUs, because these
> > > > older CPUs _do not provide_ atomic one-byte and two-byte loads and stores."
> > > >
> > >
> > > Does this apply in general or only to SMP configurations? I guess
> > > non-SMP configurations would still have problems if interrupted in the
> > > wrong place...
> >
> > And preemption could cause problems, too. So I believe that it needs
> > to be universal.
>
> Well preemption is usually caused by an interrupt, except you have a
> combined load and preempt instruction :)
Fair point! ;-)
Thanx, Paul
next prev parent reply other threads:[~2014-09-05 21:05 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-12 18:13 bit fields && data tearing Oleg Nesterov
2014-07-12 20:51 ` Oleg Nesterov
2014-07-12 23:34 ` Benjamin Herrenschmidt
2014-07-13 12:29 ` Oleg Nesterov
2014-07-13 13:15 ` Peter Hurley
2014-07-13 22:25 ` Benjamin Herrenschmidt
2014-07-15 13:54 ` Peter Hurley
2014-07-15 15:02 ` Richard Henderson
2014-09-03 22:51 ` Peter Hurley
2014-09-03 23:11 ` Benjamin Herrenschmidt
2014-09-04 8:43 ` David Laight
2014-09-04 9:52 ` Benjamin Herrenschmidt
2014-09-04 22:14 ` H. Peter Anvin
2014-09-05 0:59 ` Peter Hurley
2014-09-05 2:08 ` H. Peter Anvin
2014-09-05 15:31 ` Peter Hurley
2014-09-05 15:41 ` H. Peter Anvin
2014-09-08 17:52 ` One Thousand Gnomes
2014-09-08 17:59 ` H. Peter Anvin
2014-09-08 19:17 ` One Thousand Gnomes
2014-09-09 11:18 ` Peter Hurley
2014-09-08 22:47 ` Peter Hurley
2014-09-09 1:59 ` Paul E. McKenney
2014-09-09 11:14 ` Peter Hurley
2014-09-11 10:04 ` One Thousand Gnomes
2014-09-11 16:16 ` Paul E. McKenney
2014-09-11 20:01 ` Peter Hurley
2014-09-14 23:24 ` One Thousand Gnomes
2014-09-22 19:51 ` Paul E. McKenney
2014-09-23 18:19 ` Peter Hurley
2014-09-23 18:39 ` One Thousand Gnomes
2014-09-08 18:13 ` James Bottomley
2014-09-10 20:18 ` H. Peter Anvin
2014-09-10 21:10 ` Rob Landley
2014-09-05 2:08 ` H. Peter Anvin
2014-09-05 8:16 ` Michael Cree
2014-09-05 18:09 ` Paul E. McKenney
2014-09-05 18:31 ` Paul E. McKenney
2014-09-05 19:52 ` Peter Zijlstra
2014-09-05 20:01 ` Peter Hurley
2014-09-05 20:12 ` Peter Zijlstra
2014-09-05 20:15 ` H. Peter Anvin
2014-09-05 20:19 ` Paul E. McKenney
2014-09-05 18:50 ` Peter Hurley
2014-09-05 19:05 ` Paul E. McKenney
2014-09-05 19:24 ` Peter Hurley
2014-09-05 20:09 ` Paul E. McKenney
2014-09-05 19:38 ` Marc Gauthier
2014-09-05 20:14 ` Peter Hurley
2014-09-05 20:34 ` H. Peter Anvin
2014-09-05 20:42 ` Michael Cree
2014-09-05 20:43 ` Paul E. McKenney
2014-09-05 20:48 ` Thomas Gleixner
2014-09-05 21:05 ` Paul E. McKenney [this message]
2014-09-05 20:39 ` Michael Cree
2014-09-05 21:12 ` Peter Hurley
2014-09-05 21:27 ` Michael Cree
2014-09-05 20:42 ` Paul E. McKenney
2014-09-04 8:57 ` Mikael Pettersson
2014-09-04 9:09 ` Jakub Jelinek
2014-09-04 12:24 ` Peter Hurley
2014-09-04 12:29 ` Jakub Jelinek
2014-09-04 16:50 ` One Thousand Gnomes
2014-09-04 19:42 ` Peter Hurley
2014-09-04 22:16 ` H. Peter Anvin
2014-09-05 0:17 ` Paul E. McKenney
2014-09-05 1:57 ` Peter Hurley
2014-09-05 2:11 ` James Bottomley
2014-09-05 2:47 ` Peter Hurley
2014-09-05 4:06 ` Paul E. McKenney
2014-09-05 8:30 ` David Laight
2014-09-05 12:31 ` Peter Hurley
2014-09-05 12:37 ` David Laight
2014-09-05 16:17 ` Peter Hurley
2014-09-25 16:12 ` Pavel Machek
2014-09-07 5:07 ` James Bottomley
2014-09-07 16:21 ` Paul E. McKenney
2014-09-07 19:04 ` James Bottomley
2014-09-07 20:41 ` Peter Hurley
2014-09-08 5:50 ` James Bottomley
2014-09-08 20:45 ` Chris Metcalf
2014-09-08 22:43 ` James Bottomley
2014-09-09 2:27 ` H. Peter Anvin
2014-09-09 8:11 ` Arnd Bergmann
2014-09-08 23:30 ` Peter Hurley
2014-09-09 2:56 ` James Bottomley
2014-09-09 3:20 ` H. Peter Anvin
2014-09-09 4:30 ` H. Peter Anvin
2014-09-09 10:40 ` Peter Hurley
2014-09-10 21:48 ` James Bottomley
2014-09-10 23:50 ` Peter Hurley
2014-09-11 10:23 ` Will Deacon
2014-09-07 23:00 ` Paul E. McKenney
2014-09-07 23:17 ` H. Peter Anvin
2014-09-07 23:36 ` Paul E. McKenney
2014-09-07 23:39 ` H. Peter Anvin
2014-09-08 5:56 ` James Bottomley
2014-09-08 18:12 ` H. Peter Anvin
2014-09-08 19:09 ` James Bottomley
2014-09-08 19:12 ` H. Peter Anvin
2014-09-08 19:12 ` H. Peter Anvin
2014-09-08 22:39 ` James Bottomley
2014-09-09 2:30 ` H. Peter Anvin
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