sched: Make nr_running() return 32-bit value

Creating 2**32 tasks is impossible due to futex pid limits and wasteful
anyway. Nobody has done it.

Bring nr_running() into 32-bit world to 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/20210422200228.1423391-1-adobriyan@gmail.com

fs/proc/loadavg.c

@@ -16,7 +16,7 @@ static int loadavg_proc_show(struct seq_file *m, void *v)
 
 	get_avenrun(avnrun, FIXED_1/200, 0);
 
-	seq_printf(m, "%lu.%02lu %lu.%02lu %lu.%02lu %ld/%d %d\n",
+	seq_printf(m, "%lu.%02lu %lu.%02lu %lu.%02lu %u/%d %d\n",
 		LOAD_INT(avnrun[0]), LOAD_FRAC(avnrun[0]),
 		LOAD_INT(avnrun[1]), LOAD_FRAC(avnrun[1]),
 		LOAD_INT(avnrun[2]), LOAD_FRAC(avnrun[2]),

fs/proc/stat.c

@@ -200,7 +200,7 @@ static int show_stat(struct seq_file *p, void *v)
 		"\nctxt %llu\n"
 		"btime %llu\n"
 		"processes %lu\n"
-		"procs_running %lu\n"
+		"procs_running %u\n"
 		"procs_blocked %lu\n",
 		nr_context_switches(),
 		(unsigned long long)boottime.tv_sec,

include/linux/sched/stat.h

@@ -17,7 +17,7 @@ extern unsigned long total_forks;
 extern int nr_threads;
 DECLARE_PER_CPU(unsigned long, process_counts);
 extern int nr_processes(void);
-extern unsigned long nr_running(void);
+extern unsigned int nr_running(void);
 extern bool single_task_running(void);
 extern unsigned long nr_iowait(void);
 extern unsigned long nr_iowait_cpu(int cpu);

kernel/sched/core.c

@@ -4692,9 +4692,9 @@ context_switch(struct rq *rq, struct task_struct *prev,
  * externally visible scheduler statistics: current number of runnable
  * threads, total number of context switches performed since bootup.
  */
-unsigned long nr_running(void)
+unsigned int nr_running(void)
 {
-	unsigned long i, sum = 0;
+	unsigned int i, sum = 0;
 
 	for_each_online_cpu(i)
 		sum += cpu_rq(i)->nr_running;