Thanks. I'd forgotten about that. Anyhow, the point remains :)

Production (nginx + passenger)

        17824  1      7.8 MB  0.0 MB   nginx: master process /etc/nginx/sbin/nginx -c /etc/nginx/conf/nginx.conf
	3247   17824  8.3 MB  1.0 MB   nginx: worker process
	3685   17824  8.3 MB  1.0 MB   nginx: worker process
	3696   17824  8.2 MB  0.8 MB   nginx: worker process
	3699   17824  8.2 MB  1.0 MB   nginx: worker process
	### Processes: 5
	### Total private dirty RSS: 3.71 MB

	----- Passenger processes -----
	PID    VMSize    Private  Name
	-------------------------------
	17806  5.5 MB    0.0 MB   PassengerWatchdog
	17809  36.1 MB   2.1 MB   PassengerHelperAgent
	17814  10.9 MB   0.0 MB   PassengerLoggingAgent
	3385   424.6 MB  48.7 MB  Passenger ClassicRailsApp
	### Processes: 4
	### Total private dirty RSS: 50.79 MB

Development (Apache + mod_passenger, no Rails apps running through it at the moment)

        ---------- Apache processes ----------
	PID    PPID   VMSize    Private  Name
	--------------------------------------
	13388  20050  488.3 MB  18.8 MB  /usr/sbin/httpd -DFOREGROUND
	13389  20050  488.3 MB  18.8 MB  /usr/sbin/httpd -DFOREGROUND
	13390  20050  488.3 MB  18.8 MB  /usr/sbin/httpd -DFOREGROUND
	13391  20050  488.3 MB  18.9 MB  /usr/sbin/httpd -DFOREGROUND
	13392  20050  488.4 MB  18.9 MB  /usr/sbin/httpd -DFOREGROUND
	20050  1      406.8 MB  1.1 MB   /usr/sbin/httpd -DFOREGROUND
	### Processes: 6
	### Total private dirty RSS: 95.45 MB

        ----- Passenger processes -----
	PID    VMSize    Private  Name
	-------------------------------
	13370  212.0 MB  0.3 MB   PassengerWatchdog
	13373  491.3 MB  0.3 MB   PassengerHelperAgent
	13381  213.1 MB  0.6 MB   PassengerLoggingAgent
	### Processes: 3
	### Total private dirty RSS: 1.18 MB