sched: Make nr_iowait() return 32-bit value

Creating 2**32 tasks to wait in D-state is impossible and wasteful.

Return "unsigned int" and save on REX prefixes.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210422200228.1423391-2-adobriyan@gmail.com

fs/proc/stat.c

@@ -201,7 +201,7 @@ static int show_stat(struct seq_file *p, void *v)
 		"btime %llu\n"
 		"processes %lu\n"
 		"procs_running %u\n"
-		"procs_blocked %lu\n",
+		"procs_blocked %u\n",
 		nr_context_switches(),
 		(unsigned long long)boottime.tv_sec,
 		total_forks,

include/linux/sched/stat.h

@@ -19,7 +19,7 @@ DECLARE_PER_CPU(unsigned long, process_counts);
 extern int nr_processes(void);
 extern unsigned int nr_running(void);
 extern bool single_task_running(void);
-extern unsigned long nr_iowait(void);
+extern unsigned int nr_iowait(void);
 extern unsigned long nr_iowait_cpu(int cpu);
 
 static inline int sched_info_on(void)

kernel/sched/core.c

@@ -4774,9 +4774,9 @@ unsigned long nr_iowait_cpu(int cpu)
  * Task CPU affinities can make all that even more 'interesting'.
  */
 
-unsigned long nr_iowait(void)
+unsigned int nr_iowait(void)
 {
-	unsigned long i, sum = 0;
+	unsigned int i, sum = 0;
 
 	for_each_possible_cpu(i)
 		sum += nr_iowait_cpu(i);