2021-03-27 14:04:40

by Yue Haibing

Subject: [PATCH -next] sched/fair: Fix unused function warning

while CONFIG_NO_HZ_COMMON is not enabled, gcc warn this:

kernel/sched/fair.c:8398:13: warning: ‘update_nohz_stats’ defined but not used [-Wunused-function]
static bool update_nohz_stats(struct rq *rq)
^~~~~~~~~~~~~~~~~

Move update_nohz_stats() to #ifdef block fix this.

Signed-off-by: YueHaibing <[email protected]>
---
kernel/sched/fair.c | 40 ++++++++++++++++++----------------------
1 file changed, 18 insertions(+), 22 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 6d73bdbb2d40..c7a7ef97d167 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8395,28 +8395,6 @@ group_type group_classify(unsigned int imbalance_pct,
return group_has_spare;
}

-static bool update_nohz_stats(struct rq *rq)
-{
-#ifdef CONFIG_NO_HZ_COMMON
- unsigned int cpu = rq->cpu;
-
- if (!rq->has_blocked_load)
- return false;
-
- if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
- return false;
-
- if (!time_after(jiffies, READ_ONCE(rq->last_blocked_load_update_tick)))
- return true;
-
- update_blocked_averages(cpu);
-
- return rq->has_blocked_load;
-#else
- return false;
-#endif
-}
-
/**
* update_sg_lb_stats - Update sched_group's statistics for load balancing.
* @env: The load balancing environment.
@@ -10097,6 +10075,24 @@ static inline int on_null_domain(struct rq *rq)
}

#ifdef CONFIG_NO_HZ_COMMON
+static bool update_nohz_stats(struct rq *rq)
+{
+ unsigned int cpu = rq->cpu;
+
+ if (!rq->has_blocked_load)
+ return false;
+
+ if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
+ return false;
+
+ if (!time_after(jiffies, READ_ONCE(rq->last_blocked_load_update_tick)))
+ return true;
+
+ update_blocked_averages(cpu);
+
+ return rq->has_blocked_load;
+}
+
/*
* idle load balancing details
* - When one of the busy CPUs notice that there may be an idle rebalancing
--
2.17.1

2021-03-29 12:39:33

by Vincent Guittot

Subject: Re: [PATCH -next] sched/fair: Fix unused function warning

Hi,

On Sat, 27 Mar 2021 at 14:59, YueHaibing <[email protected]> wrote:
>
> while CONFIG_NO_HZ_COMMON is not enabled, gcc warn this:
>
> kernel/sched/fair.c:8398:13: warning: ‘update_nohz_stats’ defined but not used [-Wunused-function]
> static bool update_nohz_stats(struct rq *rq)
> ^~~~~~~~~~~~~~~~~
>
> Move update_nohz_stats() to #ifdef block fix this.

Could you add a fix tag ?
Fixes: 0826530de3cb ("sched/fair: Remove update of blocked load from
newidle_balance")

Also could you move update_nohz_stats() closer to its only caller
_nohz_idle_balance()

With these small nits above:

Reviewed-by: Vincent Guittot <[email protected]>

>
> Signed-off-by: YueHaibing <[email protected]>
> ---
> kernel/sched/fair.c | 40 ++++++++++++++++++----------------------
> 1 file changed, 18 insertions(+), 22 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 6d73bdbb2d40..c7a7ef97d167 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -8395,28 +8395,6 @@ group_type group_classify(unsigned int imbalance_pct,
> return group_has_spare;
> }
>
> -static bool update_nohz_stats(struct rq *rq)
> -{
> -#ifdef CONFIG_NO_HZ_COMMON
> - unsigned int cpu = rq->cpu;
> -
> - if (!rq->has_blocked_load)
> - return false;
> -
> - if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
> - return false;
> -
> - if (!time_after(jiffies, READ_ONCE(rq->last_blocked_load_update_tick)))
> - return true;
> -
> - update_blocked_averages(cpu);
> -
> - return rq->has_blocked_load;
> -#else
> - return false;
> -#endif
> -}
> -
> /**
> * update_sg_lb_stats - Update sched_group's statistics for load balancing.
> * @env: The load balancing environment.
> @@ -10097,6 +10075,24 @@ static inline int on_null_domain(struct rq *rq)
> }
>
> #ifdef CONFIG_NO_HZ_COMMON
> +static bool update_nohz_stats(struct rq *rq)
> +{
> + unsigned int cpu = rq->cpu;
> +
> + if (!rq->has_blocked_load)
> + return false;
> +
> + if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
> + return false;
> +
> + if (!time_after(jiffies, READ_ONCE(rq->last_blocked_load_update_tick)))
> + return true;
> +
> + update_blocked_averages(cpu);
> +
> + return rq->has_blocked_load;
> +}
> +
> /*
> * idle load balancing details
> * - When one of the busy CPUs notice that there may be an idle rebalancing
> --
> 2.17.1
>