1. 根目录:
2. include
3. asm-generic
4. cputime_nsecs.h

/*
 * Definitions for measuring cputime in nsecs resolution.
 *
 * Based on <arch/ia64/include/asm/cputime.h>
 *
 * Copyright (C) 2007 FUJITSU LIMITED
 * Copyright (C) 2007 Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 */

#ifndef _ASM_GENERIC_CPUTIME_NSECS_H
#define _ASM_GENERIC_CPUTIME_NSECS_H

#include <linux/math64.h>

typedef u64 __nocast cputime_t;
typedef u64 __nocast cputime64_t;

#define cmpxchg_cputime(ptr, old, new) cmpxchg64(ptr, old, new)

#define cputime_one_jiffy		jiffies_to_cputime(1)

#define cputime_div(__ct, divisor)  div_u64((__force u64)__ct, divisor)
#define cputime_div_rem(__ct, divisor, remainder) \
	div_u64_rem((__force u64)__ct, divisor, remainder);

/*
 * Convert cputime <-> jiffies (HZ)
 */
#define cputime_to_jiffies(__ct)	\
	cputime_div(__ct, NSEC_PER_SEC / HZ)
#define cputime_to_scaled(__ct)		(__ct)
#define jiffies_to_cputime(__jif)	\
	(__force cputime_t)((__jif) * (NSEC_PER_SEC / HZ))
#define cputime64_to_jiffies64(__ct)	\
	cputime_div(__ct, NSEC_PER_SEC / HZ)
#define jiffies64_to_cputime64(__jif)	\
	(__force cputime64_t)((__jif) * (NSEC_PER_SEC / HZ))


/*
 * Convert cputime <-> nanoseconds
 */
#define cputime_to_nsecs(__ct)		\
	(__force u64)(__ct)
#define nsecs_to_cputime(__nsecs)	\
	(__force cputime_t)(__nsecs)


/*
 * Convert cputime <-> microseconds
 */
#define cputime_to_usecs(__ct)		\
	cputime_div(__ct, NSEC_PER_USEC)
#define usecs_to_cputime(__usecs)	\
	(__force cputime_t)((__usecs) * NSEC_PER_USEC)
#define usecs_to_cputime64(__usecs)	\
	(__force cputime64_t)((__usecs) * NSEC_PER_USEC)

/*
 * Convert cputime <-> seconds
 */
#define cputime_to_secs(__ct)		\
	cputime_div(__ct, NSEC_PER_SEC)
#define secs_to_cputime(__secs)		\
	(__force cputime_t)((__secs) * NSEC_PER_SEC)

/*
 * Convert cputime <-> timespec (nsec)
 */
static inline cputime_t timespec_to_cputime(const struct timespec *val)
{
	u64 ret = val->tv_sec * NSEC_PER_SEC + val->tv_nsec;
	return (__force cputime_t) ret;
}
static inline void cputime_to_timespec(const cputime_t ct, struct timespec *val)
{
	u32 rem;

	val->tv_sec = cputime_div_rem(ct, NSEC_PER_SEC, &rem);
	val->tv_nsec = rem;
}

/*
 * Convert cputime <-> timeval (msec)
 */
static inline cputime_t timeval_to_cputime(const struct timeval *val)
{
	u64 ret = val->tv_sec * NSEC_PER_SEC + val->tv_usec * NSEC_PER_USEC;
	return (__force cputime_t) ret;
}
static inline void cputime_to_timeval(const cputime_t ct, struct timeval *val)
{
	u32 rem;

	val->tv_sec = cputime_div_rem(ct, NSEC_PER_SEC, &rem);
	val->tv_usec = rem / NSEC_PER_USEC;
}

/*
 * Convert cputime <-> clock (USER_HZ)
 */
#define cputime_to_clock_t(__ct)	\
	cputime_div(__ct, (NSEC_PER_SEC / USER_HZ))
#define clock_t_to_cputime(__x)		\
	(__force cputime_t)((__x) * (NSEC_PER_SEC / USER_HZ))

/*
 * Convert cputime64 to clock.
 */
#define cputime64_to_clock_t(__ct)	\
	cputime_to_clock_t((__force cputime_t)__ct)

#endif