[PATCH v2 -next] sched/fair: Fix unused function warning

[PATCH v2 -next] sched/fair: Fix unused function warning

[YueHaibing]

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 checking this.

Fixes: 0826530de3cb ("sched/fair: Remove update of blocked load from newidle_balance")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
---
v2: Add Fixes tag, also move update_nohz_stats() closer to its only caller _nohz_idle_balance()
---
 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..2a20ada83cbb 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.
@@ -10380,6 +10358,24 @@ void nohz_balance_enter_idle(int cpu)
 	WRITE_ONCE(nohz.has_blocked, 1);
 }
 
+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;
+}
+
 /*
  * Internal function that runs load balance for all idle cpus. The load balance
  * can be a simple update of blocked load or a complete load balance with
-- 
2.17.1

[tip: sched/core] sched/fair: Move update_nohz_stats() to the CONFIG_NO_HZ_COMMON block to simplify the code & fix an unused function warning

[tip-bot2 for YueHaibing]

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     3f5ad91488e813026f8c5f46b839e91a83912703
Gitweb:        https://git.kernel.org/tip/3f5ad91488e813026f8c5f46b839e91a83912703
Author:        YueHaibing <yuehaibing@huawei.com>
AuthorDate:    Mon, 29 Mar 2021 22:40:29 +08:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 20 Apr 2021 10:14:15 +02:00

sched/fair: Move update_nohz_stats() to the CONFIG_NO_HZ_COMMON block to simplify the code & fix an unused function warning

When !CONFIG_NO_HZ_COMMON we get this new GCC warning:

   kernel/sched/fair.c:8398:13: warning: ‘update_nohz_stats’ defined but not used [-Wunused-function]

Move update_nohz_stats() to an already existing CONFIG_NO_HZ_COMMON #ifdef
block.

Beyond fixing the GCC warning, this also simplifies the update_nohz_stats() function.

[ mingo: Rewrote the changelog. ]

Fixes: 0826530de3cb ("sched/fair: Remove update of blocked load from newidle_balance")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20210329144029.29200-1-yuehaibing@huawei.com
---
 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 49636a4..7ea3b93 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8430,28 +8430,6 @@ 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.
@@ -10406,6 +10384,24 @@ out:
 	WRITE_ONCE(nohz.has_blocked, 1);
 }
 
+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;
+}
+
 /*
  * Internal function that runs load balance for all idle cpus. The load balance
  * can be a simple update of blocked load or a complete load balance with