root/include/linux/acct.h

INCLUDED FROM

DEFINITIONS

1. jiffies_to_AHZ
2. nsec_to_AHZ

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  *  BSD Process Accounting for Linux - Definitions
   4  *
   5  *  Author: Marco van Wieringen (mvw@planets.elm.net)
   6  *
   7  *  This header file contains the definitions needed to implement
   8  *  BSD-style process accounting. The kernel accounting code and all
   9  *  user-level programs that try to do something useful with the
  10  *  process accounting log must include this file.
  11  *
  12  *  Copyright (C) 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V.
  13  *
  14  */
  15 #ifndef _LINUX_ACCT_H
  16 #define _LINUX_ACCT_H
  17 
  18 #include <uapi/linux/acct.h>
  19 
  20 
  21 
  22 #ifdef CONFIG_BSD_PROCESS_ACCT
  23 struct pid_namespace;
  24 extern int acct_parm[]; /* for sysctl */
  25 extern void acct_collect(long exitcode, int group_dead);
  26 extern void acct_process(void);
  27 extern void acct_exit_ns(struct pid_namespace *);
  28 #else
  29 #define acct_collect(x,y)       do { } while (0)
  30 #define acct_process()          do { } while (0)
  31 #define acct_exit_ns(ns)        do { } while (0)
  32 #endif
  33 
  34 /*
  35  * ACCT_VERSION numbers as yet defined:
  36  * 0: old format (until 2.6.7) with 16 bit uid/gid
  37  * 1: extended variant (binary compatible on M68K)
  38  * 2: extended variant (binary compatible on everything except M68K)
  39  * 3: new binary incompatible format (64 bytes)
  40  * 4: new binary incompatible format (128 bytes)
  41  * 5: new binary incompatible format (128 bytes, second half)
  42  *
  43  */
  44 
  45 #undef ACCT_VERSION
  46 #undef AHZ
  47 
  48 #ifdef CONFIG_BSD_PROCESS_ACCT_V3
  49 #define ACCT_VERSION    3
  50 #define AHZ             100
  51 typedef struct acct_v3 acct_t;
  52 #else
  53 #ifdef CONFIG_M68K
  54 #define ACCT_VERSION    1
  55 #else
  56 #define ACCT_VERSION    2
  57 #endif
  58 #define AHZ             (USER_HZ)
  59 typedef struct acct acct_t;
  60 #endif
  61 
  62 #include <linux/jiffies.h>
  63 /*
  64  * Yet another set of HZ to *HZ helper functions.
  65  * See <linux/jiffies.h> for the original.
  66  */
  67 
  68 static inline u32 jiffies_to_AHZ(unsigned long x)
  69 {
  70 #if (TICK_NSEC % (NSEC_PER_SEC / AHZ)) == 0
  71 # if HZ < AHZ
  72         return x * (AHZ / HZ);
  73 # else
  74         return x / (HZ / AHZ);
  75 # endif
  76 #else
  77         u64 tmp = (u64)x * TICK_NSEC;
  78         do_div(tmp, (NSEC_PER_SEC / AHZ));
  79         return (long)tmp;
  80 #endif
  81 }
  82 
  83 static inline u64 nsec_to_AHZ(u64 x)
  84 {
  85 #if (NSEC_PER_SEC % AHZ) == 0
  86         do_div(x, (NSEC_PER_SEC / AHZ));
  87 #elif (AHZ % 512) == 0
  88         x *= AHZ/512;
  89         do_div(x, (NSEC_PER_SEC / 512));
  90 #else
  91         /*
  92          * max relative error 5.7e-8 (1.8s per year) for AHZ <= 1024,
  93          * overflow after 64.99 years.
  94          * exact for AHZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
  95          */
  96         x *= 9;
  97         do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (AHZ/2))
  98                                   / AHZ));
  99 #endif
 100         return x;
 101 }
 102 
 103 #endif  /* _LINUX_ACCT_H */