3. User Interface
=================
-3.0. Configuration
-------------------
-
-a. Enable CONFIG_CGROUPS
-b. Enable CONFIG_MEMCG
-
-3.1. Prepare the cgroups (see cgroups.txt, Why are cgroups needed?)
--------------------------------------------------------------------
+To use the user interface:
-::
+1. Enable CONFIG_CGROUPS and CONFIG_MEMCG options
+2. Prepare the cgroups (see :ref:`Why are cgroups needed?
+ <cgroups-why-needed>` for the background information)::
# mount -t tmpfs none /sys/fs/cgroup
# mkdir /sys/fs/cgroup/memory
# mount -t cgroup none /sys/fs/cgroup/memory -o memory
-3.2. Make the new group and move bash into it::
+3. Make the new group and move bash into it::
# mkdir /sys/fs/cgroup/memory/0
# echo $$ > /sys/fs/cgroup/memory/0/tasks
-Since now we're in the 0 cgroup, we can alter the memory limit::
+4. Since now we're in the 0 cgroup, we can alter the memory limit::
# echo 4M > /sys/fs/cgroup/memory/0/memory.limit_in_bytes
+ The limit can now be queried::
+
+ # cat /sys/fs/cgroup/memory/0/memory.limit_in_bytes
+ 4194304
+
.. note::
We can use a suffix (k, K, m, M, g or G) to indicate values in kilo,
mega or gigabytes. (Here, Kilo, Mega, Giga are Kibibytes, Mebibytes,
.. note::
We cannot set limits on the root cgroup any more.
-::
-
- # cat /sys/fs/cgroup/memory/0/memory.limit_in_bytes
- 4194304
We can check the usage::