LXR linux-bk/include/linux/times.h

   1#ifndef _LINUX_TIMES_H
   2#define _LINUX_TIMES_H
   3
   4#ifdef __KERNEL__
   5#include <linux/timex.h>
   6#include <asm/div64.h>
   7#include <asm/types.h>
   8#include <asm/param.h>
   9
  10static inline clock_t jiffies_to_clock_t(long x)
  11{
  12#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
  13        return x / (HZ / USER_HZ);
  14#else
  15        u64 tmp = (u64)x * TICK_NSEC;
  16        do_div(tmp, (NSEC_PER_SEC / USER_HZ));
  17        return (long)tmp;
  18#endif
  19}
  20
  21static inline unsigned long clock_t_to_jiffies(unsigned long x)
  22{
  23#if (HZ % USER_HZ)==0
  24        if (x >= ~0UL / (HZ / USER_HZ))
  25                return ~0UL;
  26        return x * (HZ / USER_HZ);
  27#else
  28        u64 jif;
  29
  30        /* Don't worry about loss of precision here .. */
  31        if (x >= ~0UL / HZ * USER_HZ)
  32                return ~0UL;
  33
  34        /* .. but do try to contain it here */
  35        jif = x * (u64) HZ;
  36        do_div(jif, USER_HZ);
  37        return jif;
  38#endif
  39}
  40
  41static inline u64 jiffies_64_to_clock_t(u64 x)
  42{
  43#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
  44        do_div(x, HZ / USER_HZ);
  45#else
  46        /*
  47         * There are better ways that don't overflow early,
  48         * but even this doesn't overflow in hundreds of years
  49         * in 64 bits, so..
  50         */
  51        x *= TICK_NSEC;
  52        do_div(x, (NSEC_PER_SEC / USER_HZ));
  53#endif
  54        return x;
  55}
  56#endif
  57
  58struct tms {
  59        clock_t tms_utime;
  60        clock_t tms_stime;
  61        clock_t tms_cutime;
  62        clock_t tms_cstime;
  63};
  64
  65#endif
  66