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


Re: [Xen-devel] Re: [PATCH][HVM] fix VNIF restore failure on HVM guest w

To: "Zhai, Edwin" <edwin.zhai@xxxxxxxxx>
Subject: Re: [Xen-devel] Re: [PATCH][HVM] fix VNIF restore failure on HVM guest with heavy workload
From: Keir Fraser <keir@xxxxxxxxxxxxx>
Date: Wed, 11 Apr 2007 09:56:40 +0100
Cc: Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>, Ian Pratt <Ian.Pratt@xxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Wed, 11 Apr 2007 01:55:38 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <20070411072014.GK4593@xxxxxxxxxxxxxxxxxxxxxx>
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: Acd8F1GxkEamROgKEduOGgAX8io7RQ==
Thread-topic: [Xen-devel] Re: [PATCH][HVM] fix VNIF restore failure on HVM guest with heavy workload
User-agent: Microsoft-Entourage/
FYI, the next changeset worth testing or fixing is r14795:6e7ef794cdbc. I've
made a *lot* of changes in the last 24 hours. I've tried a few save/restores
under block and net load with no observed problems.

 -- Keir

On 11/4/07 08:20, "Zhai, Edwin" <edwin.zhai@xxxxxxxxx> wrote:

> On Tue, Apr 10, 2007 at 08:16:04PM +0100, Keir Fraser wrote:
>> On 10/4/07 17:47, "Zhai, Edwin" <edwin.zhai@xxxxxxxxx> wrote:
>>> [PATCH][HVM] fix VNIF restore failure on HVM guest with heavy workload
>>> Signed-off-by: Zhai Edwin <edwin.zhai@xxxxxxxxx>
>>> VNIF has many intrs when save/restore with net workload, so need keep
>>> handler
>>> from intrs
>> What happens if an interrupt is being processed during save/restore? It
>> would be nice to know what the underlying bug is!
> If an pseudo PCI intr occurred after xen_suspend on cpu0, there is definitely
> a 
> crash. I copy this code from original PV driver code.
>> That said, it may well make sense to somehow disable interrupt handling
>> across save/restore. Unfortunately your patch is insufficient since we could
>> handle event-channel interrupts on any VCPU (the irq's affinity can be
>> changed outside our control if it is routed through the virtual IOAPIC, and
>> if e.g. the userspace irqbalance daemon is running).
>> I wanted to use stop_machine_run() but unfortunately it isn't exported to
>> modules. :-( irq_disable() may do the right thing for us though.
> SMP is a headache for PV drv save/restore on HVM. Even we disable intr on all
> cpus, PV driver on other cpu may still access low level service after
> xen_suspend on cpu0.
> smp_suspend is used for PV drv on PV domain, which is not suitable for HVM as
> we 
> need the transparency to guest.
> Do we need lightweight stop_machine_run in this case, i.e. make other cpu
> sleep?
>>  -- Keir

Xen-devel mailing list