linux_kernel/include/linux/sched/stat.h

#ifndef _LINUX_SCHED_STAT_H
#define _LINUX_SCHED_STAT_H

#include <linux/sched.h>

/*
 * Various counters maintained by the scheduler and fork(),
 * exposed via /proc, sys.c or used by drivers via these APIs.
 *
 * ( Note that all these values are aquired without locking,
 *   so they can only be relied on in narrow circumstances. )
 */

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 bool single_task_running(void);
extern unsigned long nr_iowait(void);
extern unsigned long nr_iowait_cpu(int cpu);
extern void get_iowait_load(unsigned long *nr_waiters, unsigned long *load);

#endif /* _LINUX_SCHED_STAT_H */