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From:   Yafang Shao <laoar.shao@gmail.com>
Date:   Mon, 20 Sep 2021 14:55:29 +0800
Message-ID: <CALOAHbDYExn1uRaHX1jNZrST80if7QjA-MuL0at1C7fHzQgV8g@mail.gmail.com>
Subject: Re: linux-next: build warning after merge of the tip tree
To:     Stephen Rothwell <sfr@canb.auug.org.au>
Cc:     Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Next Mailing List <linux-next@vger.kernel.org>
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On Mon, Sep 20, 2021 at 9:33 AM Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> Hi all,
>
> After merging the tip tree, today's linux-next build (powerpc_ppc64
> defconfig) produced this warning:
>
> kernel/sched/debug.c: In function 'print_cfs_group_stats':
> kernel/sched/debug.c:460:41: warning: unused variable 'stats' [-Wunused-variable]
>   460 |                struct sched_statistics *stats =  __schedstats_from_se(se);
>       |                                         ^~~~~
>
> Caused by commit
>
>   cb3e971c435d ("sched: Make struct sched_statistics independent of fair sched class")
>
> # CONFIG_SCHEDSTATS is not set
>

Hi Stephen,

Thanks for the report.

We have discussed this issue before[1].
This warning happens when CONFIG_SCHEDSTATS is not set and
schedstat_enabled() is 0, so the whole scope should be not compiled.
It seems that we don't need to fix this warning.

[1]. https://lore.kernel.org/lkml/20210911082505.115758-1-laoar.shao@gmail.com/

-- 
Thanks
Yafang