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" determines what kind of information is returned. This argument is optional, the default mode is "stats". - "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"): { "locked": { (json object) Information about locked memory manager "used": xxxxx, (numeric) Number of bytes used "free": xxxxx, (numeric) Number of bytes available in current arenas "total": xxxxxxx, (numeric) Total number of bytes managed "locked": xxxxxx, (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": xxxxx, (numeric) Number allocated chunks "chunks_free": xxxxx, (numeric) Number unused chunks } } Result (mode "mallocinfo"): "..." 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/