WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] regression from c/s 22071:c5aed2e049bc (ept: Put locks a

To: "Keir Fraser" <keir@xxxxxxx>
Subject: Re: [Xen-devel] regression from c/s 22071:c5aed2e049bc (ept: Put locks around ept_get_entry) ?
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Date: Thu, 16 Dec 2010 16:50:35 +0000
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, Christoph Egger <Christoph.Egger@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Thu, 16 Dec 2010 08:51:18 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C92FF206.D1D6%keir@xxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <4D0A4AC90200007800028731@xxxxxxxxxxxxxxxxxx> <C92FF206.D1D6%keir@xxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>>> On 16.12.10 at 17:42, Keir Fraser <keir@xxxxxxx> wrote:
> The issue is not one of serialisation or code ordering. It is one of
> memory-access atomicity. Thus it seems to me that volatile is the correct

Indeed, I agree.

> approach therefore. Perhaps *(volatile type *)px = x or, really, even better
> I should define some {read,write}_atomic{8,16,32,64} accessor functions
> which use inline asm to absolutely definitely emit a single atomic 'mov'
> instruction.
> 
> Make sense?

Yes.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>