This change allows for the testing of cli_monitor's automatic resource
balancing by executing the following command:
start ram_eater --ram-limit 1G --count 5
The command starts 5 instances of a RAM-eating process, which is,
however, able to yield resources when instructed. The RAM quota for the
processes gets automatically extended because of the overly large limit
of 1 GiB, which is far more than CLI monitor's RAM resources (100 MiB).
When the RAM usage hits the preservation limit, CLI monitor broadcasts
yield requests to each ram_eater instance, which allow the scenario to
remain alive.
This patch introduces new commands for dynamically balancing RAM between
subsystems. The 'status' command prints a table with the RAM status of
each subsystem. The 'ram' command changes the quota or a quota limit of
a given subsystem. The quota limit can be defined to allow the on-demand
expansion of the quota. Finally, the 'yield' command can be used to
instruct a subsystem to yield a specified amount of resources.
For trying out the new commands, a so-called 'ram_eater' example has
been added to the 'terminal_mux.run' scenario. This program simulates a
subsystem with a growing demand for resources, yet with the capability
to yield resources when instructed by the parent (i.e., cli_monitor).
Besides implementing the new features, the patch splits the
implementation of 'cli_monitor' into multiple files.
The new terminal_mux server is able to provide multiple terminal
sessions over one terminal-client session. The user can switch
between the different sessions using the keyboard shortcut C-y,
which brings up an ncurses-based menu.
Norman Feske
Christian Prochaska