sched: Make nr_iowait_cpu() return 32-bit value

Runqueue ->nr_iowait counters are 32-bit anyway.

Propagate 32-bitness into other code, but don't try too hard.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210422200228.1423391-3-adobriyan@gmail.com

drivers/cpuidle/governors/menu.c

@@ -117,7 +117,7 @@ struct menu_device {
 	int		interval_ptr;
 };
 
-static inline int which_bucket(u64 duration_ns, unsigned long nr_iowaiters)
+static inline int which_bucket(u64 duration_ns, unsigned int nr_iowaiters)
 {
 	int bucket = 0;
 
@@ -150,7 +150,7 @@ static inline int which_bucket(u64 duration_ns, unsigned long nr_iowaiters)
  * to be, the higher this multiplier, and thus the higher
  * the barrier to go to an expensive C state.
  */
-static inline int performance_multiplier(unsigned long nr_iowaiters)
+static inline int performance_multiplier(unsigned int nr_iowaiters)
 {
 	/* for IO wait tasks (per cpu!) we add 10x each */
 	return 1 + 10 * nr_iowaiters;
@@ -270,7 +270,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
 	unsigned int predicted_us;
 	u64 predicted_ns;
 	u64 interactivity_req;
-	unsigned long nr_iowaiters;
+	unsigned int nr_iowaiters;
 	ktime_t delta, delta_tick;
 	int i, idx;
 

include/linux/sched/stat.h

@@ -20,7 +20,7 @@ extern int nr_processes(void);
 extern unsigned int nr_running(void);
 extern bool single_task_running(void);
 extern unsigned int nr_iowait(void);
-extern unsigned long nr_iowait_cpu(int cpu);
+extern unsigned int nr_iowait_cpu(int cpu);
 
 static inline int sched_info_on(void)
 {

kernel/sched/core.c

@@ -4739,7 +4739,7 @@ unsigned long long nr_context_switches(void)
  * it does become runnable.
  */
 
-unsigned long nr_iowait_cpu(int cpu)
+unsigned int nr_iowait_cpu(int cpu)
 {
 	return atomic_read(&cpu_rq(cpu)->nr_iowait);
 }