It's a bit hard to comment without more details and without seeing your code. Here's an example I have for using 
DCMD_PROC_PAGEDATA. It is meant to check the effect of MAP_LAZY and it looks at the current process, but the principles 
are the same for what you are trying to do:

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <devctl.h>
#include <sys/mman.h>
#include <sys/procfs.h>

int
main(int argc, char **argv)
{
    // Map a page using MAP_LAZY.
    void    *ptr = mmap(0, __PAGESIZE * 10, PROT_READ | PROT_WRITE,
                        MAP_ANON | MAP_PRIVATE | MAP_LAZY, NOFD, 0);
    if (ptr == MAP_FAILED) {
        perror("mmap");
        return 1;
    }

    printf("ptr=%p\n", ptr);

    // Open the devctl interface for this process.
    int fd = open("/proc/self/ctl", O_RDWR);
    if (fd == -1) {
        perror("open");
        return 1;
    }

    // Ask for up to 32 mapinfo entries.
    procfs_mapinfo  mapinfo[32];
    memset(mapinfo, 0, sizeof(mapinfo));
    if (devctl(fd, DCMD_PROC_PAGEDATA, mapinfo, sizeof(mapinfo), NULL) == -1) {
        perror("devctl");
        return 1;
    }

    // Print results.
    for (int i = 0; i < 32; i++) {
        printf("vaddr=%lx size=%zu flags=%x paddr=%lx\n",
               (uintptr_t)mapinfo[i].vaddr,
               (size_t)mapinfo[i].size,
               mapinfo[i].flags,
               (uintptr_t)mapinfo[i].paddr);
    }

    return 0;
}

The output looks like:

ptr=9053000
vaddr=7fc7000 size=4096 flags=1083082 paddr=ffffffffffffffff
vaddr=7fc8000 size=516096 flags=1083382 paddr=ffffffffffffffff
vaddr=8046000 size=8192 flags=1783382 paddr=43b82e000
vaddr=8048000 size=4096 flags=1600571 paddr=43b80d000
vaddr=8049000 size=2097152 flags=10800a2 paddr=ffffffffffffffff
vaddr=8249000 size=4096 flags=1600132 paddr=43b87f000
vaddr=824a000 size=4096 flags=1700332 paddr=43beb7000
vaddr=9048000 size=20480 flags=1780302 paddr=432206000
vaddr=904d000 size=24576 flags=1080302 paddr=ffffffffffffffff
vaddr=9053000 size=40960 flags=1080382 paddr=ffffffffffffffff
vaddr=905d000 size=4096 flags=1780302 paddr=43b7fa000
vaddr=905e000 size=24576 flags=1080302 paddr=ffffffffffffffff
vaddr=9064000 size=4096 flags=1780302 paddr=43b774000
vaddr=100000000 size=221184 flags=610571 paddr=126a000
vaddr=100036000 size=2093056 flags=10800a2 paddr=ffffffffffffffff
vaddr=100235000 size=8192 flags=610172 paddr=43b4d0000
vaddr=100237000 size=4096 flags=710372 paddr=43b852000
vaddr=100238000 size=4096 flags=1780332 paddr=43b881000
vaddr=100239000 size=724992 flags=610571 paddr=1124000
vaddr=1002ea000 size=2097152 flags=1080022 paddr=ffffffffffffffff
vaddr=1004ea000 size=16384 flags=1680132 paddr=44a5ee000
vaddr=1004ee000 size=8192 flags=710372 paddr=43b7fd000
vaddr=1004f0000 size=12288 flags=1780332 paddr=43b725000
vaddr=1004f3000 size=90112 flags=610571 paddr=11dc000
vaddr=100509000 size=2093056 flags=1080022 paddr=ffffffffffffffff
vaddr=100708000 size=4096 flags=1680132 paddr=43b74a000
vaddr=100709000 size=4096 flags=710372 paddr=43b826000
vaddr=0 size=0 flags=0 paddr=0
vaddr=0 size=0 flags=0 paddr=0
vaddr=0 size=0 flags=0 paddr=0
vaddr=0 size=0 flags=0 paddr=0
vaddr=0 size=0 flags=0 paddr=0

--Elad