Re: [PATCH v1] sched/topology: Make compiler happy about unused constant definitions

From: Andy Shevchenko
Date: Tue Aug 25 2020 - 04:39:50 EST


On Mon, Aug 24, 2020 at 06:09:41PM +0100, Valentin Schneider wrote:
> On 24/08/20 16:39, Andy Shevchenko wrote:
> > Compilation of almost each file ends up with
> >
> > In file included from .../include/linux/energy_model.h:10,
> > from .../include/linux/device.h:16,
> > from .../drivers/spi/spi.c:8:
> > .../include/linux/sched/topology.h:30:27: warning: ‘SD_DEGENERATE_GROUPS_MASK’ defined but not used [-Wunused-const-variable=]
> > 30 | static const unsigned int SD_DEGENERATE_GROUPS_MASK =
> > | ^~~~~~~~~~~~~~~~~~~~~~~~~
> > ...
> >
> > Make compiler happy by annotating the static constants with __maybwe_unused.
> >
>
> That should see some use as long as the build is for SMP. This whole region
> is guarded by #ifdef CONFIG_SMP, so an !SMP build shouldn't trigger this.

Isn't SMP is default for most of the kernel builds?
And honestly I didn't get the purpose of this comment.

> With what config/kernel are you getting this?

x86_64_defconfig from the kernel sources with some drivers added (SMP or so has
not been touched, DEBUG_SHED was enabled once to confirm that another static
const has same issue).

--
With Best Regards,
Andy Shevchenko