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/
Home Products Support Community News


[Xen-devel] Re: Is QoS of virtual disk not necessary?

To: Andi Kleen <andi@xxxxxxxxxxxxxx>
Subject: [Xen-devel] Re: Is QoS of virtual disk not necessary?
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Fri, 24 Aug 2007 18:40:54 +0100
Cc: Satoshi Uchida <s-uchida@xxxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Fri, 24 Aug 2007 10:41:45 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <p73d4xcyhbo.fsf@xxxxxxxxxxxxxx>
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/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcfmdeuAKdw/glJpEdyhNgAX8io7RQ==
Thread-topic: Is QoS of virtual disk not necessary?
User-agent: Microsoft-Entourage/
On 24/8/07 18:26, "Andi Kleen" <andi@xxxxxxxxxxxxxx> wrote:

>> Another nice thing would be that if we do not use CFQ then we do not need a
>> kernel thread per VBD.
> It would be probably easy to extend CFQ2 to use an user passed identifier
> instead of per task for sharing if that's your goal. For a kernel driver
> like blkback you could just switch around multiple current->io_contexts.

Does current->io_context get latched before submit_bh() (or whatever similar
function it is we use) returns? Is this true even in older 2.6 kernels with
old CFQ?

 -- Keir

Xen-devel mailing list