PSSt (short for PSS tree) is a simple utility that shows memory usage for every process as well as their children, taking shared memory into account. tmpfs file systems, unreclaimable SLAB caches, and zram devices are also reported.

Sample output:

     PSS    ∑ PSS    PID command or mount point
  159.0k    12.8G      1 init [3]
    5.5M     7.0G  19645 ├ urxvt
    1.4M     7.0G  19646 │ └ bash
    1.0G     7.0G  19649 │   └ /opt/firefox/firefox-bin --name firefox-bin
  860.5M   860.5M  19937 │     ├ /opt/firefox/firefox-bin ...
  859.4M   859.4M  19817 │     ├ /opt/firefox/firefox-bin ...
    ...      ...    ...  │     ├ (...skipped for brevity...)
    7.4M     7.4M  20137 │     └ /opt/firefox/firefox-bin ...
    1.0G     1.0G  tmpfs ├ /dev/shm
    ...      ...    ...  ├ ...