[libvirt] [PATCH 2/6] Make state driver device hotplug/update actually transient

[Daniel P. Berrange]

On Mon, Nov 22, 2010 at 04:35:30PM -0500, Cole Robinson wrote:
> The current semantics of non-persistent hotplug/update are confusing: the
> changes will persist as long as the in memory domain definition isn't
> overwritten. This means hotplug changes stay around until the domain is
> redefined or libvirtd is restarted.
> 
> Call virDomainObjSetDefTransient at VM startup, so that we properly discard
> hotplug changes when the VM is shutdown.
> 
> Signed-off-by: Cole Robinson <crobinso at redhat.com>
> ---
>  src/lxc/lxc_driver.c   |    3 +++
>  src/qemu/qemu_driver.c |    5 +++++
>  src/test/test_driver.c |   42 ++++++++++++++++++++++++------------------
>  src/uml/uml_driver.c   |    5 ++++-
>  4 files changed, 36 insertions(+), 19 deletions(-)

The downside is that we double the memory consumption for every
VM, regardless of whether we ever make any live config changes
to the VM. Calling SetDefTransient at time of change though
is probably too error prone.

ACK

Daniel