#define _GNU_SOURCE             /* See feature_test_macros(7) */
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <assert.h>

#define MEMSIZE (128 * 1024 * 1024)

char *testcase_description = "Separate file shared mapping page fault";

void testcase(unsigned long long *iterations)
{
        char tmpfile[4096];
        sprintf(&tmpfile[0], "/tmp/willitscale.%d.XXXXXX", sched_getcpu());
        int fd;
        unsigned long pgsize = getpagesize();

        if (1) {
                fd = open(tmpfile, O_RDWR|O_CREAT, 0755); //mkstemp(tmpfile);
        } else {
                fd = mkstemp(tmpfile);
                unlink(tmpfile);
        }
        assert(fd >= 0);
        assert(ftruncate(fd, MEMSIZE) == 0);

        while (1) {
                unsigned long i;

                char *c = mmap(NULL, MEMSIZE, PROT_READ|PROT_WRITE,
                               MAP_SHARED, fd, 0);
                assert(c != MAP_FAILED);

                for (i = 0; i < MEMSIZE; i += pgsize) {
                        c[i] = 0;
                        (*iterations)++;
                }

                munmap(c, MEMSIZE);
        }
}