Re: [PATCH] build: check drivers class dependencies early

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, Aug 01, 2023 at 12:20:47PM +0200, David Marchand wrote:
> On Tue, Aug 1, 2023 at 11:25 AM Bruce Richardson
> <bruce.richardson@intel.com> wrote:
> >
> > On Tue, Aug 01, 2023 at 10:52:53AM +0200, David Marchand wrote:
> > > Drivers implementing a class of devices (for example, drivers/event)
> > > depend on the associated abstraction library (lib/eventdev).
> > > This dependency is expressed in the top level meson.build for this class
> > > (drivers/event/meson.build).
> > >
> > > As we are making more libraries optional, custom constructs referencing
> > > the class dependencies in some drivers meson.build (event/dlb2) may break.
> > >
> > > It would be possible to add more checks in those drivers meson.build but
> > > it is more straightforward to not even consider a driver meson.build when
> > > the class dependencies are not met.
> > >
> > > Signed-off-by: David Marchand <david.marchand@redhat.com>
> > > ---
> > >  drivers/meson.build | 11 +++++++++++
> > >  1 file changed, 11 insertions(+)
> > >
> > > diff --git a/drivers/meson.build b/drivers/meson.build
> > > index 74ae8cb96b..c375352e77 100644
> > > --- a/drivers/meson.build
> > > +++ b/drivers/meson.build
> > > @@ -70,6 +70,17 @@ foreach subpath:subdirs
> > >      else
> > >          class = subpath
> > >          subdir(class)
> > > +        skip_class = false
> > > +        foreach d:std_deps
> > > +            if not is_variable('shared_rte_' + d)
> > > +                skip_class = true
> > > +                message('Disabling all @1@ drivers: missing internal dependency "@0@"'
> > > +                        .format(d, class))
> > > +            endif
> > > +        endforeach
> > > +        if skip_class
> > > +            continue
> > > +        endif
> > >      endif
> > >
> > >      # save class name on first occurrence
> >
> > I like this approach. However, we do need something in the summary at the
> > end of the build too. Either:
> >
> > * Single message stating all drivers of a given class are skipped
> > * (as now), message for each driver stating that it has been disabled
> >
> > The former is nice as it gives us a shorter summary. The latter is nice
> > because it's consistent with what we have now.  Authors choice, which to go
> > for! :-)
> 
> I like the shorter summary.
> WDYT of:
> 
> diff --git a/drivers/meson.build b/drivers/meson.build
> index c375352e77..02268918e4 100644
> --- a/drivers/meson.build
> +++ b/drivers/meson.build
> @@ -74,11 +74,18 @@ foreach subpath:subdirs
>          foreach d:std_deps
>              if not is_variable('shared_rte_' + d)
>                  skip_class = true
> -                message('Disabling all @1@ drivers: missing internal
> dependency "@0@"'
> +                reason = 'missing internal dependency, "@0@"'.format(d)
> +                if dpdk_libs_deprecated.contains(d)
> +                    reason += ' (deprecated lib)'
> +                endif
> +                message('Disabling @1@/* drivers: missing internal
> dependency "@0@"'
>                          .format(d, class))

Minor nit: You probably want a break here, as we only have room for one
missing dependency, so no point in checking more after the first missing.

>              endif
>          endforeach
>          if skip_class
> +            drv_path = join_paths(class, '*')
> +            dpdk_drvs_disabled += drv_path
> +            set_variable(drv_path.underscorify() + '_disable_reason', reason)
>              continue
>          endif
>      endif
> 
> 
> This gives the following output (testing on top of your series
> extending optional libs and a fix on the new reasm perf test).
> https://github.com/david-marchand/dpdk/actions/runs/5725429526/job/15513923381#step:19:346
> 
> ...
> =================
> Content Skipped
> =================
> ...
> drivers:
> ...
>     mempool/dpaa2: not in enabled drivers build config
>     mempool/octeontx: not in enabled drivers build config
>     mempool/stack: not in enabled drivers build config
>     dma/*: missing internal dependency, "dmadev"
>     net/af_packet: not in enabled drivers build config
>     net/af_xdp: not in enabled drivers build config
>     net/ark: not in enabled drivers build config
> ...
> 

+1 to this. Works for me.