[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] Migration downtime more than 5s when migrating guest wi
|
From: |
Yang Hongyang |
|
Subject: |
Re: [Qemu-devel] Migration downtime more than 5s when migrating guest with massive disks |
|
Date: |
Mon, 22 May 2017 20:40:11 +0800 |
|
User-agent: |
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 |
On 2017/5/22 20:26, Paolo Bonzini wrote:
>
>
> On 20/05/2017 02:46, Yang Hongyang wrote:
>>>> How about do O(1) for stopping stage of live migration?
>>>> Because the cpu is stopped in this phase, it wouldn't cause
>>>> side effects IMHO, right?
>>> O(1) update is probably not quite possible, but it's possible to do one
>>> O(n) update. We tried doing that, but something in virtio broke.
>> How were you do that? did you put extra begin/commit before/after destination
>> guest load, so that the destination guest only do one update(of n devs)
>> throughout
>> the whole migration?
>>
>
> Right. However, this is a problem if post_load hooks do DMA. You need
> to move that DMA to a VM RunState change notifier.
Right. How about force memory_region_commit before post_load if a device
has post_load hook?
>
> Paolo
>
--
Thanks,
Yang