From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Avi Kivity <avi@redhat.com>
Cc: Glauber Costa <glommer@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Marcelo Tosatti <mtosatti@redhat.com>,
Zachary Amsden <zamsden@redhat.com>
Subject: Re: [PATCH 1/5] Add a global synchronization point for pvclock
Date: Mon, 19 Apr 2010 09:11:54 -0700 [thread overview]
Message-ID: <4BCC80CA.90902@goop.org> (raw)
In-Reply-To: <4BCC69D5.3050209@redhat.com>
On 04/19/2010 07:33 AM, Avi Kivity wrote:
> On 04/19/2010 05:21 PM, Glauber Costa wrote:
>>
>>> Oh yes, just trying to avoid a patch with both atomic64_read() and
>>> ACCESS_ONCE().
>>>
>> you're mixing the private version of the patch you saw with this one.
>> there isn't any atomic reads in here. I'll use a barrier then
>>
>
> This patch writes last_value atomically, but reads it non-atomically.
> A barrier is insufficient.
Well, on a 32b system, you can explicitly order the updates of low and
high, then do a high-low-checkhigh read. That would be much more
efficient than atomic64. If we really care about 32b.
J
next prev parent reply other threads:[~2010-04-19 16:11 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-15 18:37 [PATCH 0/5] pv clock misc fixes Glauber Costa
2010-04-15 18:37 ` [PATCH 1/5] Add a global synchronization point for pvclock Glauber Costa
2010-04-15 18:37 ` [PATCH 2/5] change msr numbers for kvmclock Glauber Costa
2010-04-15 18:37 ` [PATCH 3/5] Try using new kvm clock msrs Glauber Costa
2010-04-15 18:37 ` [PATCH 4/5] export new cpuid KVM_CAP Glauber Costa
2010-04-15 18:37 ` [PATCH 5/5] add documentation about kvmclock Glauber Costa
2010-04-15 19:28 ` Randy Dunlap
2010-04-15 20:10 ` Glauber Costa
2010-04-17 18:58 ` [PATCH 4/5] export new cpuid KVM_CAP Avi Kivity
2010-04-19 14:50 ` Glauber Costa
2010-04-20 9:29 ` Avi Kivity
2010-04-17 18:55 ` [PATCH 3/5] Try using new kvm clock msrs Avi Kivity
2010-04-17 18:51 ` [PATCH 2/5] change msr numbers for kvmclock Avi Kivity
2010-04-16 20:23 ` [PATCH 1/5] Add a global synchronization point for pvclock Marcelo Tosatti
2010-04-16 20:36 ` Jeremy Fitzhardinge
2010-04-16 21:05 ` Zachary Amsden
2010-04-19 10:39 ` Peter Zijlstra
2010-04-19 10:50 ` Avi Kivity
2010-04-19 11:05 ` Peter Zijlstra
2010-04-19 11:10 ` Avi Kivity
2010-04-19 14:21 ` Glauber Costa
2010-04-19 14:33 ` Avi Kivity
2010-04-19 14:46 ` Peter Zijlstra
2010-04-19 16:18 ` Jeremy Fitzhardinge
2010-04-20 9:31 ` Avi Kivity
2010-04-20 18:23 ` Jeremy Fitzhardinge
2010-04-20 18:54 ` Avi Kivity
2010-04-20 19:42 ` Jeremy Fitzhardinge
2010-04-21 0:07 ` Zachary Amsden
2010-04-22 13:11 ` Glauber Costa
2010-04-23 1:44 ` Zachary Amsden
2010-04-23 9:34 ` Avi Kivity
2010-04-23 19:22 ` Jeremy Fitzhardinge
2010-04-23 19:25 ` Avi Kivity
2010-04-23 21:31 ` Zachary Amsden
2010-04-23 21:35 ` Jeremy Fitzhardinge
2010-04-23 21:41 ` Zachary Amsden
2010-04-24 9:30 ` Avi Kivity
2010-04-24 9:29 ` Avi Kivity
2010-04-19 16:11 ` Jeremy Fitzhardinge [this message]
2010-04-19 14:26 ` Glauber Costa
2010-04-19 16:19 ` Jeremy Fitzhardinge
2010-04-19 18:25 ` Glauber Costa
2010-04-20 1:57 ` Marcelo Tosatti
2010-04-20 9:35 ` Avi Kivity
2010-04-20 12:59 ` Glauber Costa
2010-04-20 15:16 ` Avi Kivity
2010-04-21 0:01 ` Zachary Amsden
2010-04-21 8:06 ` Avi Kivity
2010-04-17 18:48 ` Avi Kivity
2010-04-17 18:49 ` Avi Kivity
2010-04-19 10:43 ` Peter Zijlstra
2010-04-19 10:47 ` Avi Kivity
2010-04-19 10:56 ` Peter Zijlstra
2010-04-19 11:13 ` Avi Kivity
2010-04-19 11:19 ` Peter Zijlstra
2010-04-19 11:40 ` Avi Kivity
2010-04-19 14:32 ` Glauber Costa
2010-04-19 14:37 ` Avi Kivity
2010-04-19 10:46 ` Peter Zijlstra
2010-04-19 10:49 ` Avi Kivity
2010-04-19 10:51 ` Peter Zijlstra
2010-04-19 10:54 ` Avi Kivity
2010-04-19 18:35 ` Zachary Amsden
2010-04-20 9:39 ` Avi Kivity
2010-04-21 0:05 ` Zachary Amsden
2010-04-21 8:08 ` Avi Kivity
2010-04-19 10:49 ` Peter Zijlstra
2010-04-19 10:53 ` Avi Kivity
2010-04-19 10:59 ` Peter Zijlstra
2010-04-19 11:35 ` Avi Kivity
2010-10-25 23:30 ` Jeremy Fitzhardinge
2010-10-26 8:14 ` Avi Kivity
2010-10-26 10:49 ` Glauber Costa
2010-10-26 17:04 ` Jeremy Fitzhardinge
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