#include <fcntl.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
int main() {
int fd = open("/dev/zero", O_RDWR);
if (fd == -1) perror("open(/dev/zero)"), exit(1);
for (size_t mmap_size = 64ull << 30; mmap_size >= 4 << 10; mmap_size /= 2) {
size_t allocated = 0;
while (mmap(0, mmap_size, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE,
fd, 0) != MAP_FAILED) {
allocated += mmap_size;
}
fprintf(stderr, "allocated %zu with size %zu\n", allocated, mmap_size);
}
fprintf(stderr, "DONE\n");
_exit(0);
}