jvm - Does RSS tracks reserved or commited memory? -

i'm running experiments different jvm options on java 8 in order lower rss:

• script used rss tracking:

  ps -o rss -o vsz -o pid $pid

• jvm args setting java process:

  -xx:+printnmtstatistics -xx:+unlockdiagnosticvmoptions -xx:nativememorytracking=detail

• taking baseline jcmd:

  jcmd $pid vm.native_memory baseline

• taking diff jcmd:

  jcmd $pid vm.native_memory summary.diff

output (partial thread area):

-                    thread (reserved=130696kb -21564kb, committed=130696kb -21564kb)                             (thread #121 -21)                             (stack: reserved=130048kb -21504kb, committed=130048kb -21504kb)                             (malloc=379kb -67kb #610 -105)                             (arena=268kb +7 #240 -42) 

question: memory taken account rss output above, committed or reserved?

the relation between reserved/committed , resident/virtual little more complex. rss covers pages resident in physical memory. things have been paged out (or never paged in) can be committed memory not resident.

maybe answers question: reserved-but-not-committed pages cannot resident.