#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#include <asm/page.h>
#include <errno.h>

#define SIZE (1024 * 1024 * 1024)

int main(int argc, char *argv[])
{
  char *addr;
  int i;

  if ((addr = mmap(0, SIZE, PROT_READ | PROT_WRITE,
      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0)) != MAP_FAILED) {
    printf("You have more than %i memory, increase SIZE\n", SIZE);
    return 1;
  }
  perror("mmap()");
  printf("OK, now trying uncommited...\n");
  if ((addr = mmap(0, SIZE, PROT_NONE,
      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0)) == MAP_FAILED) {
    perror("mmap()");
    return 1;
  }
  if (mprotect(addr, SIZE, PROT_READ | PROT_WRITE) == -1) {
    perror("mprotect()");
    return 1;
  }

  printf("Memory of size %i successfully committed!\n", SIZE);
  printf("overcommit_memory: ");
  fflush(stdout);
  system("cat /proc/sys/vm/overcommit_memory");

  for (i = 0; i < SIZE; i += PAGE_SIZE) {
    addr[i] = 1;
  }

  return 0;
}