#include <iostream>
#include <sstream>
#include <stdlib.h>
#include <sys/mman.h>
#include <string.h>
#include <stdio.h>

void usage()
{
  std::cout << "Usage: dirty_ram <MB>\n";
  exit(1);
}

int main(int argc, char **argv)
{
  if (argc != 2)
    usage();

  size_t mb;
  std::istringstream argin(argv[1]);
  argin >> mb;
  if (!argin)
    usage();

  size_t size = mb * 1048576;
  void *buf = mmap(0, size,
		   PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS,
		   -1, 0);
  if (buf == MAP_FAILED) {
    perror("mmap");
    return 1;
  }

  memset(buf, 1, size);
  return 0;
}