Created attachment 114218 [details]
Fix set_nice() to use private bus connections

Hi

In src/pulsecore/core-util.c:set_nice() we currently use a temporary dbus-connection to set the nice-level via rtkit. However, we never close that connection. This is fine, as the connection is shared and dbus-core will manage it. But no other part of pulseaudio (with one exception, see below) uses the libdbus1 managed connections. Therefore, we effectively end up with an unused dbus-connection that is not integrated into any main-loop. dbus-daemon will send bus-notifications to the connection (as libdbus1 installs matches for those by default (it has to!)) until the outgoing queue is full. Thus, we waste several KBs (or MBs? I didn't look it up) of memory for a message queue that is never dispatched.

If you look at set_scheduler() in the same file, you see the only other user of libdbus1 without pa_dbus. However, it correctly uses a private bus connection via dbus_get_bus_private(). It also correctly closes _and_ unref's it after it's done.

Note that you cannot call dbus_connection_close() on shared connections. Therefore, I recommend fixing set_nice() to work exactly like set_scheduler(). An untested patch is attached. I don't have any clue what the rtkit stuff does, so I cannot really test it. I hope you guys can give it a try.

Thanks
David