From: Valentin Schneider <valentin.schneider@arm.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
linux-kernel@vger.kernel.org,
Dietmar Eggemann <dietmar.eggemann@arm.com>
Subject: Re: [PATCH v1] sched/topology: Make compiler happy about unused constant definitions
Date: Tue, 25 Aug 2020 13:00:12 +0100 [thread overview]
Message-ID: <jhja6yjdjg3.mognet@arm.com> (raw)
In-Reply-To: <20200825113202.GX1891694@smile.fi.intel.com>
On 25/08/20 12:32, Andy Shevchenko wrote:
> On Tue, Aug 25, 2020 at 02:26:05PM +0300, Andy Shevchenko wrote:
>> On Tue, Aug 25, 2020 at 02:24:05PM +0300, Andy Shevchenko wrote:
>> > On Tue, Aug 25, 2020 at 11:12:21AM +0100, Valentin Schneider wrote:
>> > > On 25/08/20 10:03, Valentin Schneider wrote:
>> > > > On 25/08/20 09:26, Andy Shevchenko wrote:
>> > > >> 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.
>> > >
>> > > > Sorry, that's what I get for trying to be too succinct; what I tried to say
>> > > > was that SD_DEGENERATE_GROUPS_MASK should very much be used for SMP. If the
>> > > > build is !SMP, it shouldn't even be defined, IOW I'm perplexed as to where
>> > > > this is coming from.
>> > >
>> > > So I see how having this as a constvar rather than a constexpr is somewhat
>> > > daft (we get an instance per compilation unit), but none of my compilers
>> > > seem to complain (even with W=1). AFAIA the kernelbot didn't catch any of
>> > > it either.
>
> And even without compiler or any other analyzer / bot I can 100% sure tell that
> spi.c does *not* use that symbol.
Aye aye, this is a daft constvar placement from my end, apologies.
For the SD_DEGENERATE_GROUPS_MASK, that one could directly be shoved into
kernel/sched/topology.c (or done via an enum, I don't care too much).
I suppose the other one causing you grief is sd_flag_debug[]; that one too
really shouldn't be in a header. I need to access that in two separate
files, so I guess I'll have to cook up some wrappers.
Let me take a jab at it, it's my own mess after all...
next prev parent reply other threads:[~2020-08-25 12:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-24 15:39 [PATCH v1] sched/topology: Make compiler happy about unused constant definitions Andy Shevchenko
2020-08-24 17:09 ` Valentin Schneider
2020-08-25 8:26 ` Andy Shevchenko
2020-08-25 9:03 ` Valentin Schneider
2020-08-25 10:12 ` Valentin Schneider
2020-08-25 11:24 ` Andy Shevchenko
2020-08-25 11:26 ` Andy Shevchenko
2020-08-25 11:32 ` Andy Shevchenko
2020-08-25 12:00 ` Valentin Schneider [this message]
2020-08-25 12:38 ` Andy Shevchenko
2020-08-25 10:23 ` David Laight
2020-08-25 11:30 ` 'Andy Shevchenko'
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