Documentation of miscellaneous cgroup controller. This new controller is
used to track and limit the usage of scalar resources.
Signed-off-by: Vipin Sharma <vipinsh@xxxxxxxxxx>
Reviewed-by: David Rientjes <rientjes@xxxxxxxxxx>
---
Documentation/admin-guide/cgroup-v1/index.rst | 1 +
Documentation/admin-guide/cgroup-v1/misc.rst | 4 +
Documentation/admin-guide/cgroup-v2.rst | 73 ++++++++++++++++++-
3 files changed, 76 insertions(+), 2 deletions(-)
create mode 100644 Documentation/admin-guide/cgroup-v1/misc.rst
diff --git a/Documentation/admin-guide/cgroup-v1/index.rst b/Documentation/admin-guide/cgroup-v1/index.rst
index 226f64473e8e..99fbc8a64ba9 100644
--- a/Documentation/admin-guide/cgroup-v1/index.rst
+++ b/Documentation/admin-guide/cgroup-v1/index.rst
@@ -17,6 +17,7 @@ Control Groups version 1
hugetlb
memcg_test
memory
+ misc
net_cls
net_prio
pids
diff --git a/Documentation/admin-guide/cgroup-v1/misc.rst b/Documentation/admin-guide/cgroup-v1/misc.rst
new file mode 100644
index 000000000000..661614c24df3
--- /dev/null
+++ b/Documentation/admin-guide/cgroup-v1/misc.rst
@@ -0,0 +1,4 @@
+===============
+Misc controller
+===============
+Please refer "Misc" documentation in Documentation/admin-guide/cgroup-v2.rst
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 64c62b979f2f..b1e81aa8598a 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -65,8 +65,11 @@ v1 is available under :ref:`Documentation/admin-guide/cgroup-v1/index.rst <cgrou
5-7-1. RDMA Interface Files
5-8. HugeTLB
5.8-1. HugeTLB Interface Files
- 5-8. Misc
- 5-8-1. perf_event
+ 5-9. Misc
+ 5.9-1 Miscellaneous cgroup Interface Files
+ 5.9-2 Migration and Ownership
+ 5-10. Others
+ 5-10-1. perf_event
5-N. Non-normative information
5-N-1. CPU controller root cgroup process behaviour
5-N-2. IO controller root cgroup process behaviour
@@ -2171,6 +2174,72 @@ HugeTLB Interface Files
Misc
----
+The Miscellaneous cgroup provides the resource limiting and tracking
+mechanism for the scalar resources which cannot be abstracted like the other
+cgroup resources. Controller is enabled by the CONFIG_CGROUP_MISC config
+option.
+
+A resource can be added to the controller via enum misc_res_type{} in the
+include/linux/misc_cgroup.h file and the corresponding name via misc_res_name[]
+in the kernel/cgroup/misc.c file. Provider of the resource must set its
+capacity prior to using the resource by calling misc_cg_set_capacity().
+
+Once a capacity is set then the resource usage can be updated using charge and
+uncharge APIs. All of the APIs to interact with misc controller are in
+include/linux/misc_cgroup.h.
+
+Misc Interface Files
+~~~~~~~~~~~~~~~~~~~~
+
+Miscellaneous controller provides 3 interface files. If two misc resources (res_a and res_b) are registered then:
+
+ misc.capacity
+ A read-only flat-keyed file shown only in the root cgroup. It shows
+ miscellaneous scalar resources available on the platform along with
+ their quantities::
+
+ $ cat misc.capacity
+ res_a 50
+ res_b 10
+
+ misc.current
+ A read-only flat-keyed file shown in the non-root cgroups. It shows
+ the current usage of the resources in the cgroup and its children.::
+
+ $ cat misc.current
+ res_a 3
+ res_b 0
+
+ misc.max
+ A read-write flat-keyed file shown in the non root cgroups. Allowed
+ maximum usage of the resources in the cgroup and its children.::
+
+ $ cat misc.max
+ res_a max
+ res_b 4
+
+ Limit can be set by::
+
+ # echo res_a 1 > misc.max
+
+ Limit can be set to max by::
+
+ # echo res_a max > misc.max
+
+ Limits can be set higher than the capacity value in the misc.capacity
+ file.
+
+Migration and Ownership
+~~~~~~~~~~~~~~~~~~~~~~~
+
+A miscellaneous scalar resource is charged to the cgroup in which it is used
+first, and stays charged to that cgroup until that resource is freed. Migrating
+a process to a different cgroup does not move the charge to the destination
+cgroup where the process has moved.
+
+Others
+------
+
perf_event
~~~~~~~~~~
--
2.31.0.291.g576ba9dcdaf-goog
