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From: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
To: Ingo Molnar <mingo@redhat.com>, Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] kernel/sched/core.c: Avoid unused variable on non-SMP configs
Date: Sat, 8 Sep 2018 21:05:53 +0200	[thread overview]
Message-ID: <20180908190553.GA4573@gmail.com> (raw)

On non-SMP configs, when only one of CONFIG_{PARAVIRT,IRQ_TIME}_ACCOUNTING
is defined, we are declaring a variable (irq_delta or steal) which
is not used:

    kernel/sched/core.c: In function ‘update_rq_clock_task’:
    kernel/sched/core.c:139:17: warning: unused variable ‘irq_delta’ [-Wunused-variable]
      s64 steal = 0, irq_delta = 0;

The reason is that CONFIG_SMP guards HAVE_SCHED_AVG_IRQ, which in turn
disables the code guarded by HAVE_SCHED_AVG_IRQ.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
---
 kernel/sched/core.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 625bc9897f62..d662d1e11843 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -135,8 +135,11 @@ static void update_rq_clock_task(struct rq *rq, s64 delta)
  * In theory, the compile should just see 0 here, and optimize out the call
  * to sched_rt_avg_update. But I don't trust it...
  */
-#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
-	s64 steal = 0, irq_delta = 0;
+#if defined(HAVE_SCHED_AVG_IRQ) || defined(CONFIG_IRQ_TIME_ACCOUNTING)
+	s64 irq_delta = 0;
+#endif
+#if defined(HAVE_SCHED_AVG_IRQ) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
+	s64 steal = 0;
 #endif
 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
 	irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
-- 
2.17.1


             reply	other threads:[~2018-09-08 19:07 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-08 19:05 Miguel Ojeda [this message]
2018-09-09  9:36 ` [PATCH] kernel/sched/core.c: Avoid unused variable on non-SMP configs Borislav Petkov
2018-09-09 14:48   ` Miguel Ojeda
2018-09-09 16:06     ` Borislav Petkov
2018-09-09 16:36       ` Miguel Ojeda
2018-09-09 16:45         ` Borislav Petkov
2018-09-09 16:59           ` Miguel Ojeda
2018-09-10  7:00             ` Vincent Guittot
2018-09-10 10:32               ` Miguel Ojeda
2018-09-10 12:34                 ` Vincent Guittot

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