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From:   Alex Dewar <alex.dewar90@gmail.com>
Date:   Tue, 18 Aug 2020 20:57:46 +0100
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Alex Dewar <alex.dewar90@gmail.com>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        LKML <linux-kernel@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH] sched/cputime: Mark function as __maybe_unused
Message-ID: <20200818195746.scpjm3dlg7cfst53@medion>
References: <20200818170337.805624-1-alex.dewar90@gmail.com>
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On Tue, Aug 18, 2020 at 11:13:10AM -0700, Nick Desaulniers wrote:
> On Tue, Aug 18, 2020 at 10:04 AM Alex Dewar <alex.dewar90@gmail.com> wrote:
> >
> > Depending on config options, account_other_time() may not be called
> > anywhere. Add __maybe_unused flag to fix clang warning.
> 
> Just curious, would moving this definition to be within an existing
> preprocessor guard for a particular config also fix the issue? If so,
> prefer that. If not, __maybe_unused is the way to go.

I don't think that'd work here: it's used within an "#ifdef
CONFIG_IRQ_TIME_ACCOUNTING" block and a separate "#ifdef
CONFIG_VIRT_CPU_ACCOUNTING_GEN" one. We could do:
	#if defined(CONFIG_IRQ_TIME_ACCOUNTING) ||
	    defined(CONFIG_VIRT_CPU_ACCOUNTING)
		...
... but that might be a bit ugly.

> 
> >
> > Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
> > ---
> >  kernel/sched/cputime.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
> > index 5a55d2300452..43ede0d6661c 100644
> > --- a/kernel/sched/cputime.c
> > +++ b/kernel/sched/cputime.c
> > @@ -252,7 +252,7 @@ static __always_inline u64 steal_account_process_time(u64 maxtime)
> >  /*
> >   * Account how much elapsed time was spent in steal, irq, or softirq time.
> >   */
> > -static inline u64 account_other_time(u64 max)
> > +static inline u64 __maybe_unused account_other_time(u64 max)
> >  {
> >         u64 accounted;
> >
> > --
> > 2.28.0
> >
> > --
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> 
> 
> 
> -- 
> Thanks,
> ~Nick Desaulniers