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Re: device compatibility interface for live migration with assigned devi
From: |
Yan Zhao |
Subject: |
Re: device compatibility interface for live migration with assigned devices |
Date: |
Mon, 31 Aug 2020 12:43:44 +0800 |
User-agent: |
Mutt/1.9.4 (2018-02-28) |
On Fri, Aug 28, 2020 at 03:04:12PM +0100, Sean Mooney wrote:
> On Fri, 2020-08-28 at 15:47 +0200, Cornelia Huck wrote:
> > On Wed, 26 Aug 2020 14:41:17 +0800
> > Yan Zhao <yan.y.zhao@intel.com> wrote:
> >
> > > previously, we want to regard the two mdevs created with dsa-1dwq x 30 and
> > > dsa-2dwq x 15 as compatible, because the two mdevs consist equal
> > > resources.
> > >
> > > But, as it's a burden to upper layer, we agree that if this condition
> > > happens, we still treat the two as incompatible.
> > >
> > > To fix it, either the driver should expose dsa-1dwq only, or the target
> > > dsa-2dwq needs to be destroyed and reallocated via dsa-1dwq x 30.
> >
> > AFAIU, these are mdev types, aren't they? So, basically, any management
> > software needs to take care to use the matching mdev type on the target
> > system for device creation?
>
> or just do the simple thing of use the same mdev type on the source and dest.
> matching mdevtypes is not nessiarly trivial. we could do that but we woudl
> have
> to do that in python rather then sql so it would be slower to do at least
> today.
>
> we dont currently have the ablity to say the resouce provider must have 1 of
> these
> set of traits. just that we must have a specific trait. this is a feature we
> have
> disucssed a couple of times and delayed untill we really really need it but
> its not out
> of the question that we could add it for this usecase. i suspect however we
> would do exact
> match first and explore this later after the inital mdev migration works.
Yes, I think it's good.
still, I'd like to put it more explicitly to make ensure it's not missed:
the reason we want to specify compatible_type as a trait and check
whether target compatible_type is the superset of source
compatible_type is for the consideration of backward compatibility.
e.g.
an old generation device may have a mdev type xxx-v4-yyy, while a newer
generation device may be of mdev type xxx-v5-yyy.
with the compatible_type traits, the old generation device is still
able to be regarded as compatible to newer generation device even their
mdev types are not equal.
Thanks
Yan
> by the way i was looking at some vdpa reslated matiail today and noticed vdpa
> devices are nolonger
> usign mdevs and and now use a vhost chardev so i guess we will need a
> completely seperate mechanioum
> for vdpa vs mdev migration as a result. that is rather unfortunet but i guess
> that is life.
> >
>
- Re: device compatibility interface for live migration with assigned devices, (continued)
- Re: device compatibility interface for live migration with assigned devices, Alex Williamson, 2020/08/19
- Re: device compatibility interface for live migration with assigned devices, Yan Zhao, 2020/08/19
- Re: device compatibility interface for live migration with assigned devices, Cornelia Huck, 2020/08/25
- Re: device compatibility interface for live migration with assigned devices, Yan Zhao, 2020/08/26
- Re: device compatibility interface for live migration with assigned devices, Cornelia Huck, 2020/08/28
- Re: device compatibility interface for live migration with assigned devices, Sean Mooney, 2020/08/28
- Re: device compatibility interface for live migration with assigned devices,
Yan Zhao <=
- Re: device compatibility interface for live migration with assigned devices, Yan Zhao, 2020/08/30
- Re: device compatibility interface for live migration with assigned devices, Jason Wang, 2020/08/18
- RE: device compatibility interface for live migration with assigned devices, Parav Pandit, 2020/08/18
- Re: device compatibility interface for live migration with assigned devices, Jason Wang, 2020/08/18
- RE: device compatibility interface for live migration with assigned devices, Parav Pandit, 2020/08/19
- Re: device compatibility interface for live migration with assigned devices, Jason Wang, 2020/08/19
- RE: device compatibility interface for live migration with assigned devices, Parav Pandit, 2020/08/19
- Re: device compatibility interface for live migration with assigned devices, Cornelia Huck, 2020/08/18
- Re: device compatibility interface for live migration with assigned devices, Daniel P . Berrangé, 2020/08/18
- Re: device compatibility interface for live migration with assigned devices, Cornelia Huck, 2020/08/18