cgroup: document cgroup_no_v1=
Add cgroup_no_v1= to kernel-parameters.txt, and a small blurb to
cgroup-v2.txt section about transitioning from cgroup to cgroup2.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index 9ae148a..3922ae1 100644
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -132,6 +132,12 @@
the hierarchies and controller associations before starting using the
controllers after system boot.
+During transition to v2, system management software might still
+automount the v1 cgroup filesystem and so hijack all controllers
+during boot, before manual intervention is possible. To make testing
+and experimenting easier, the kernel parameter cgroup_no_v1= allows
+disabling controllers in v1 and make them always available in v2.
+
2-2. Organizing Processes
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index cfb2c0f..0d962a1 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -608,6 +608,11 @@
cut the overhead, others just disable the usage. So
only cgroup_disable=memory is actually worthy}
+ cgroup_no_v1= [KNL] Disable one, multiple, all cgroup controllers in v1
+ Format: { controller[,controller...] | "all" }
+ Like cgroup_disable, but only applies to cgroup v1;
+ the blacklisted controllers remain available in cgroup2.
+
cgroup.memory= [KNL] Pass options to the cgroup memory controller.
Format: <string>
nosocket -- Disable socket memory accounting.