Note on memory footprint

Author: sandhose

synapse/README.rst

@@ -51,3 +51,10 @@ An example configuration setting these and a custom prefix would like::
 
     experimental_features:
       msc3886_endpoint: /rendezvous # this should match above
+
+^^^^^^^^^^^^
+Memory usage
+^^^^^^^^^^^^
+
+`max_entries` and `max_bytes` allow to tune how much memory the module may take.
+There is a constant overhead of approximately 1KiB per entry, so with the default config (`max_bytes = 4KiB, max_entries = 10000`), the maximum theorical memory footprint of the moduel is `(4KiB + 1KiB) * 10000 = 50MiB`.