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Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command |
Date: |
Fri, 26 Jun 2009 10:42:24 +0100 |
User-agent: |
Mutt/1.4.1i |
On Fri, Jun 26, 2009 at 12:21:01PM +0300, Avi Kivity wrote:
> On 06/25/2009 10:11 PM, Luiz Capitulino wrote:
> >
> > Yes, having a library was suggested by Amit some months ago. The
> >problem is that it has various issues wrt maintainability.
> >
> > For example, libvirt is able to run two instances of different
> >versions of qemu at the same time. How to handle this if you
> >update libmonitor.so?
> >
The sane way is to *NOT* break ABI of libmonitor.so, and not change
the wire protocol in a non backwards compatible way. This is entirely
doable, it just the maintainer of libmonitor/qemu to decide that ABI
stability is important. So if you find an existing API / command
needs to gain an extra argument, you don't change the existing API,
you add a new one. Or ideally design the API upfront so that it
can be extended without breaking back compatability.
> You could use dlopen(). The problem with a library is that it assumes
> everyone is still trapped in C, which is not the case.
dlopen() of a different libmonitor.so for every version of QEMU is just
crazy, whether C or not. Maintain ABI & protocol back compatability
with new releases and avoid the issue in the first place.
Daniel
--
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- [Qemu-devel] [PATCH 08/11] QMP: Port balloon command, Luiz Capitulino, 2009/06/23
- [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Avi Kivity, 2009/06/23
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Anthony Liguori, 2009/06/23
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Luiz Capitulino, 2009/06/23
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Anthony Liguori, 2009/06/23
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Dor Laor, 2009/06/25
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Luiz Capitulino, 2009/06/25
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Avi Kivity, 2009/06/26
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command,
Daniel P. Berrange <=
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Avi Kivity, 2009/06/26
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Luiz Capitulino, 2009/06/27
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Avi Kivity, 2009/06/28
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Blue Swirl, 2009/06/28
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Filip Navara, 2009/06/28
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Avi Kivity, 2009/06/28
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Blue Swirl, 2009/06/28
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Avi Kivity, 2009/06/28
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Jamie Lokier, 2009/06/28
- Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command, Anthony Liguori, 2009/06/25