The getmemoryinfo RPC returns information about memory usage.
getmemoryinfo ("mode")
*bitcoin-cli help getmemoryinfo
getmemoryinfo ( "mode" ) Returns an object containing information about memory usage. Arguments: 1. mode (string, optional, default="stats") determines what kind of information is returned. - "stats" returns general statistics about memory usage in the daemon. - "mallocinfo" returns an XML string describing low-level heap state (only available if compiled with glibc 2.10+). Result (mode "stats"): { (json object) "locked" : { (json object) Information about locked memory manager "used" : n, (numeric) Number of bytes used "free" : n, (numeric) Number of bytes available in current arenas "total" : n, (numeric) Total number of bytes managed "locked" : n, (numeric) Amount of bytes that succeeded locking. If this number is smaller than total, locking pages failed at some point and key data could be swapped to disk. "chunks_used" : n, (numeric) Number allocated chunks "chunks_free" : n (numeric) Number unused chunks } } Result (mode "mallocinfo"): "str" (string) "..." Examples: > bitcoin-cli getmemoryinfo > curl --user myusername --data-binary '{"jsonrpc": "1.0", "id": "curltest", "method": "getmemoryinfo", "params": []}' -H 'content-type: text/plain;' http://127.0.0.1:8332/