(ejabberd@ip-10-19-17-221)1> erlang:memory().
[{total,1879496184},
 {processes,1101731992},
 {processes_used,1101731400},
 {system,777764192},
 {atom,1033401},
 {atom_used,1012541},
 {binary,75551632},
 {code,24569808},
 {ets,30400408}]
(ejabberd@ip-10-19-17-221)2> lists:foreach(fun erlang:garbage_collect/1, processes()). 
ok
(ejabberd@ip-10-19-17-221)3> 
(ejabberd@ip-10-19-17-221)3> erlang:memory().
[{total,1011509088},
 {processes,261563416},
 {processes_used,261561928},
 {system,749945672},
 {atom,1033401},
 {atom_used,1012541},
 {binary,47658592},
 {code,24569808},
 {ets,30400408}]