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[66.187.233.206]) by smtp.gmail.com with ESMTPSA id l19sm4294245qtb.6.2019.07.08.07.32.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 08 Jul 2019 07:32:45 -0700 (PDT) Message-ID: <1562596364.8510.1.camel@lca.pw> Subject: Re: [PATCH v2] sched/core: silence a warning in sched_init() From: Qian Cai To: mingo@redhat.com, peterz@infradead.org Cc: valentin.schneider@arm.com, linux-kernel@vger.kernel.org Date: Mon, 08 Jul 2019 10:32:44 -0400 In-Reply-To: <1561466662-22314-1-git-send-email-cai@lca.pw> References: <1561466662-22314-1-git-send-email-cai@lca.pw> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6 (3.22.6-10.el7) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ping. Per discussion, sounds like this is the best thing to do in order to avoid compilation warnings. On Tue, 2019-06-25 at 08:44 -0400, Qian Cai wrote: > Compiling a kernel with both FAIR_GROUP_SCHED=n and RT_GROUP_SCHED=n > will generate a warning using W=1, > > kernel/sched/core.c: In function 'sched_init': > kernel/sched/core.c:5906:32: warning: variable 'ptr' set but not used > [-Wunused-but-set-variable] >   unsigned long alloc_size = 0, ptr; >                                 ^~~ > > It apparently the maintainers don't like the previous fix [1] which > contains ugly idefs, so silence it by appending the __maybe_unused > attribute for it instead. > > [1] https://lore.kernel.org/lkml/1559681162-5385-1-git-send-email-cai@lca.pw/ > > Reviewed-by: Valentin Schneider > Signed-off-by: Qian Cai > --- > > v2: Incorporate the feedback from Valentin. > >  kernel/sched/core.c | 3 ++- >  1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 874c427742a9..12b9b69c8a66 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -5903,7 +5903,8 @@ int in_sched_functions(unsigned long addr) >  void __init sched_init(void) >  { >   int i, j; > - unsigned long alloc_size = 0, ptr; > + unsigned long alloc_size = 0; > + unsigned long __maybe_unused ptr; >   >   wait_bit_init(); >