postgres=# select numa_zone_id, count(*) from pg_buffercache group by numa_zone_id;
NOTICE:  os_page_count=32768 os_page_size=4096 pages_per_blk=2.000000
 numa_zone_id | count
--------------+-------
              | 16149
            4 |    59
            0 |    59
            6 |    58
            2 |    59
(5 rows)

postgres=# create table xx as select generate_series(1, 1000000);
SELECT 1000000
postgres=# select numa_zone_id, count(*) from pg_buffercache group by numa_zone_id;
NOTICE:  os_page_count=32768 os_page_size=4096 pages_per_blk=2.000000
 numa_zone_id | count
--------------+-------
              | 14095
            4 |   572
            0 |   572
            6 |   571
            2 |   572
           -2 |     2
(6 rows)

postgres=# show shared_buffers ;
 shared_buffers
----------------
 128MB
(1 row)

postgres=# select pg_backend_pid();
 pg_backend_pid
----------------
          14121
(1 row)


## and now from 14121:

postgres=# select numa_zone_id, count(*) from pg_buffercache group by numa_zone_id;
NOTICE:  os_page_count=32768 os_page_size=4096 pages_per_blk=2.000000
 numa_zone_id | count
--------------+-------
              | 13439
            4 |    46
            0 |    48
            6 |    47
            2 |    47
           -2 |  2757

## also, this wont give us detailed addr <-> specific NUMA node info:
postgres@jw-test3:~$ grep --color /dev/zero /proc/14121/numa_maps
7f5dd6004000 interleave:0-7 file=/dev/zero\040(deleted) dirty=6829 mapmax=7 active=0 N0=853 N1=853 N2=855 N3=853 N4=852 N5=854 N6=854 N7=855 kernelpagesize_kB=4