[dpdk-dev] [RFC v2] meter: fix ABI break due to experimental tag removal

[Thomas Monjalon]

30/01/2020 13:57, Luca Boccassi:
> On Thu, 2020-01-30 at 13:33 +0100, Thomas Monjalon wrote:
> > Hi,
> > 
> > I disagree with the need of this patch.
> > The symbol was experimental, meaning we can change it.
> > Removing experimental tag is not an ABI break.
> 
> Hi,
> 
> This symbol change was requested for backport in 19.11.x, and
> experimental or not I'm not too keen on backward incompatible changes
> to the public interface in an _LTS point release_. The compromise was
> to see if we could support both symbols version, which makes the change
> backward compatible.
> 
> If you prefer not to have this patch in mainline I'm also fine in
> taking it just for the LTS. I agree with you that it is not required
> for mainline releases (although nicer for me if it's a backport rather
> than a new change).

I would like to avoid opening the door for maintaining the experimental ABI
in the mainline. Please take it directly in the LTS.

The next question is to know whether we really want to have such patch in LTS.
Anyway, 19.11.0 has this symbol as experimental.
How adding a non-experimental version of the function in 19.11.1 will change
the ABI status of the whole 19.11 branch?



> > 29/01/2020 17:43, Ferruh Yigit:
> > > Duplicated the existing symbol and versioned one as experimental
> > > and
> > > other as stable.
> > 
> > [..]
> > > --- a/lib/librte_meter/rte_meter_version.map
> > > +++ b/lib/librte_meter/rte_meter_version.map
> > > @@ -20,4 +20,12 @@ DPDK_20.0.1 {
> > >  	rte_meter_trtcm_rfc4115_color_blind_check;
> > >  	rte_meter_trtcm_rfc4115_config;
> > >  	rte_meter_trtcm_rfc4115_profile_config;
> > > +
> > >  } DPDK_20.0;
> > > +
> > > +EXPERIMENTAL {
> > > +       global:
> > > +
> > > +	rte_meter_trtcm_rfc4115_config;
> > > +	rte_meter_trtcm_rfc4115_profile_config;
> > > +};