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 <mi...@redhat.com> Cc: Peter Zijlstra <pet...@infradead.org> Signed-off-by: Miguel Ojeda <miguel.ojeda.sando...@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