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Re: [Qemu-ppc] [Qemu-devel] [PATCH 5/5] spapr: drop DIV_ROUND_UP() from
From: |
Daniel P . Berrangé |
Subject: |
Re: [Qemu-ppc] [Qemu-devel] [PATCH 5/5] spapr: drop DIV_ROUND_UP() from xics_max_server_number() |
Date: |
Thu, 15 Feb 2018 16:54:18 +0000 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
On Thu, Feb 15, 2018 at 05:08:57PM +0100, Greg Kurz wrote:
> On Thu, 15 Feb 2018 15:08:18 +1100
> David Gibson <address@hidden> wrote:
>
> > On Wed, Feb 14, 2018 at 08:41:03PM +0100, Greg Kurz wrote:
>
> <snip>
>
> > >
> > > It breaks migration of pre-2.7 machine types with unusual CPU topologies,
> > > but I guess this is an acceptable trade-off.
> >
> > No, not really. Weird topologies are still allowed on old machine
> > types for backwards compatibility, and we shouldn't break that. I
> > like the idea of consolidating this calculation, but we can't do it by
> > just breaking the older machines (at least not until they're formally
> > deprecated).
> >
>
> Heh, I had put this patch at the end because I was expecting you might
> nack it :)
>
> Per curiosity, when/how do we decide that an older machine type may be
> formally deprecated ?
For versioned machine types we decided that we'd keep them around upstream
for as long as they were needed by a downstream vendor, *provided* that
downstream vendor is contributing to QEMU in order to mitigate the maint
burden it would entail.
Regards,
Daniel
--
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- [Qemu-ppc] [PATCH 1/5] spapr: use spapr->vsmt to compute VCPU ids, (continued)
- [Qemu-ppc] [PATCH 1/5] spapr: use spapr->vsmt to compute VCPU ids, Greg Kurz, 2018/02/14
- [Qemu-ppc] [PATCH 2/5] spapr: move VCPU calculation to core machine code, Greg Kurz, 2018/02/14
- [Qemu-ppc] [PATCH 3/5] spapr: rename spapr_vcpu_id() to spapr_get_vcpu_id(), Greg Kurz, 2018/02/14
- [Qemu-ppc] [PATCH 4/5] spapr: consolidate the VCPU id numbering logic in a single place, Greg Kurz, 2018/02/14
- [Qemu-ppc] [PATCH 5/5] spapr: drop DIV_ROUND_UP() from xics_max_server_number(), Greg Kurz, 2018/02/14