WSL2-Linux-Kernel/tools/testing/selftests/size/get_size.c

101 строка
2.4 KiB
C

/*
* Copyright 2014 Sony Mobile Communications Inc.
*
* Licensed under the terms of the GNU GPL License version 2
*
* Selftest for runtime system size
*
* Prints the amount of RAM that the currently running system is using.
*
* This program tries to be as small as possible itself, to
* avoid perturbing the system memory utilization with its
* own execution. It also attempts to have as few dependencies
* on kernel features as possible.
*
* It should be statically linked, with startup libs avoided.
* It uses no library calls, and only the following 3 syscalls:
* sysinfo(), write(), and _exit()
*
* For output, it avoids printf (which in some C libraries
* has large external dependencies) by implementing it's own
* number output and print routines, and using __builtin_strlen()
*/
#include <sys/sysinfo.h>
#include <unistd.h>
#define STDOUT_FILENO 1
static int print(const char *s)
{
return write(STDOUT_FILENO, s, __builtin_strlen(s));
}
static inline char *num_to_str(unsigned long num, char *buf, int len)
{
unsigned int digit;
/* put digits in buffer from back to front */
buf += len - 1;
*buf = 0;
do {
digit = num % 10;
*(--buf) = digit + '0';
num /= 10;
} while (num > 0);
return buf;
}
static int print_num(unsigned long num)
{
char num_buf[30];
return print(num_to_str(num, num_buf, sizeof(num_buf)));
}
static int print_k_value(const char *s, unsigned long num, unsigned long units)
{
unsigned long long temp;
int ccode;
print(s);
temp = num;
temp = (temp * units)/1024;
num = temp;
ccode = print_num(num);
print("\n");
return ccode;
}
/* this program has no main(), as startup libraries are not used */
void _start(void)
{
int ccode;
struct sysinfo info;
unsigned long used;
print("Testing system size.\n");
print("1..1\n");
ccode = sysinfo(&info);
if (ccode < 0) {
print("not ok 1 get runtime memory use\n");
print("# could not get sysinfo\n");
_exit(ccode);
}
/* ignore cache complexities for now */
used = info.totalram - info.freeram - info.bufferram;
print_k_value("ok 1 get runtime memory use # size = ", used,
info.mem_unit);
print("# System runtime memory report (units in Kilobytes):\n");
print_k_value("# Total: ", info.totalram, info.mem_unit);
print_k_value("# Free: ", info.freeram, info.mem_unit);
print_k_value("# Buffer: ", info.bufferram, info.mem_unit);
print_k_value("# In use: ", used, info.mem_unit);
_exit(0);
}