[PATCH v3 12/13] docs: cgroup-v2: Document kernel-noise isolation via isolated partitions

[Jing Wu <realwujing@gmail.com>]

Document that cpuset.cpus.partition=isolated now drives runtime updates
of the housekeeping masks for kernel-noise types: nohz_full (tick
suppression), RCU NOCB offloading, and managed IRQ migration.  No
additional cgroupfs files are required; the partition update path
automatically triggers explicit housekeeping callbacks for all affected
subsystems.

Signed-off-by: Jing Wu <realwujing@gmail.com>
Signed-off-by: Qiliang Yuan <yuanql9@chinatelecom.cn>
---
 Documentation/admin-guide/cgroup-v2.rst | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 6efd0095ed995..7c3b048e75cb5 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -2721,6 +2721,14 @@ Cpuset Interface Files
 	kernel boot command line option.  If those CPUs are to be put
 	into a partition, they have to be used in an isolated partition.
 
+	When an isolated partition is created or destroyed, the kernel
+	automatically drives runtime updates of the housekeeping masks
+	for kernel-noise types (nohz_full, RCU NOCB, managed IRQ
+	interrupts).  This extends isolation beyond scheduler domains:
+	the tick is stopped on isolated CPUs, RCU callbacks are
+	offloaded to housekeeping cores, and managed interrupts are
+	migrated away.  No additional cgroupfs files are required.
+
 
 Device controller
 -----------------

-- 
2.43.0