On Wed, Jul 12, 2017 at 04:04:00PM +0100, Daniel P. Berrange wrote: > On Wed, Jul 12, 2017 at 10:22:33AM +0200, Thomas Huth wrote: > > We don't want to carry along old machine types forever. If we are able to > > remove the pc machines up to 0.13 one day for example, this would allow > > us to eventually kill the code for rombar=0 (i.e. where QEMU copies ROM > > BARs directly to low memory). Everything up to pc-1.2 is also known to > > have issues with migration. So let's start with a deprecation message > > for the old machine types so that the (hopefully) few users of these old > > systems start switching over to newer machine types instead. > > I think we must document & agree on our support policy for machine > types, before we start marking them as deprecated. eg please consider > the following document before accepting this deprecation patch: > > https://lists.gnu.org/archive/html/qemu-devel/2017-07/msg00652.html > > Note in that proposal there, I say we do *not* go through trouble of > explicitly marking machines as deprecated. We just document upfront > the intended lifecycle and then delete them when it is done. > > Just use deprecation warnings for things where there is no predictable > lifecycle upfront.
I'd bet most people won't read the deprecation policy documentation, and a deprecation warning for 1 or 2 releases would be still useful before we finally remove a machine-type. -- Eduardo
