LXR linux/tools/testing/selftests/size/get

   1/*
   2 * Copyright 2014 Sony Mobile Communications Inc.
   3 *
   4 * Licensed under the terms of the GNU GPL License version 2
   5 *
   6 * Selftest for runtime system size
   7 *
   8 * Prints the amount of RAM that the currently running system is using.
   9 *
  10 * This program tries to be as small as possible itself, to
  11 * avoid perturbing the system memory utilization with its
  12 * own execution.  It also attempts to have as few dependencies
  13 * on kernel features as possible.
  14 *
  15 * It should be statically linked, with startup libs avoided.
  16 * It uses no library calls, and only the following 3 syscalls:
  17 *   sysinfo(), write(), and _exit()
  18 *
  19 * For output, it avoids printf (which in some C libraries
  20 * has large external dependencies) by  implementing it's own
  21 * number output and print routines, and using __builtin_strlen()
  22 */
  23
  24#include <sys/sysinfo.h>
  25#include <unistd.h>
  26
  27#define STDOUT_FILENO 1
  28
  29static int print(const char *s)
  30{
  31        return write(STDOUT_FILENO, s, __builtin_strlen(s));
  32}
  33
  34static inline char *num_to_str(unsigned long num, char *buf, int len)
  35{
  36        unsigned int digit;
  37
  38        /* put digits in buffer from back to front */
  39        buf += len - 1;
  40        *buf = 0;
  41        do {
  42                digit = num % 10;
  43                *(--buf) = digit + '0';
  44                num /= 10;
  45        } while (num > 0);
  46
  47        return buf;
  48}
  49
  50static int print_num(unsigned long num)
  51{
  52        char num_buf[30];
  53
  54        return print(num_to_str(num, num_buf, sizeof(num_buf)));
  55}
  56
  57static int print_k_value(const char *s, unsigned long num, unsigned long units)
  58{
  59        unsigned long long temp;
  60        int ccode;
  61
  62        print(s);
  63
  64        temp = num;
  65        temp = (temp * units)/1024;
  66        num = temp;
  67        ccode = print_num(num);
  68        print("\n");
  69        return ccode;
  70}
  71
  72/* this program has no main(), as startup libraries are not used */
  73void _start(void)
  74{
  75        int ccode;
  76        struct sysinfo info;
  77        unsigned long used;
  78
  79        print("Testing system size.\n");
  80        print("1..1\n");
  81
  82        ccode = sysinfo(&info);
  83        if (ccode < 0) {
  84                print("not ok 1 get runtime memory use\n");
  85                print("# could not get sysinfo\n");
  86                _exit(ccode);
  87        }
  88        /* ignore cache complexities for now */
  89        used = info.totalram - info.freeram - info.bufferram;
  90        print_k_value("ok 1 get runtime memory use # size = ", used,
  91                info.mem_unit);
  92
  93        print("# System runtime memory report (units in Kilobytes):\n");
  94        print_k_value("#   Total:  ", info.totalram, info.mem_unit);
  95        print_k_value("#   Free:   ", info.freeram, info.mem_unit);
  96        print_k_value("#   Buffer: ", info.bufferram, info.mem_unit);
  97        print_k_value("#   In use: ", used, info.mem_unit);
  98
  99        _exit(0);
 100}
 101