Meaning of ram.current in _cat/nodes

In my elasticsearch cluster of 3 nodes, following is the memory usage as reported by _cat/nodes/ : -

name ram.current
es01 61.9gb
es02 62.5gb
es03 52.4gb

and following is the memory usage of elasticsearch process as checked by "top" : -

es01 : - VIRT : 217 g, RES : 34g , SHR : 2.0g
Total memory usage of system :- Mem: 62.867G total, 61.625G used, 10.784G cached ,538.797M buffers

It is similar for all the 3 systems, resident memory in use by elasticsearch is about 34 gb, i am using a max heap size limit of 30 gb.

Overall memory usage of systems is close to what is showed by ram.current, so does it show the memory usage of the system es is running on? or the memory usage of es process?

Seems like the first to me, however https://www.elastic.co/guide/en/elasticsearch/reference/current/cat-nodes.html "Used total memory" which is not clear.

If you want to double check how much heap is used, there is also a section that is specific to heap. Ram info includes heap and off heap data. Lucene relies on file system cache for its data structures, plus if you use doc_values those go off-heap as well.