github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-06-01 11:03:43 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

cgroup, docs: Be explicit about independence of RT_GROUP_SCHED and non-cpu controllers

Browse Source 
The cgroup v2 cpu controller has a limitation that if
CONFIG_RT_GROUP_SCHED is enabled, the cpu controller can be enabled only
if all the realtime processes are in the root cgroup. The other
controllers have no such restriction. They can be used for the resource
control of realtime processes irrespective of whether
CONFIG_RT_GROUP_SCHED is enabled or not.

Signed-off-by: Shashank Balaji <shashank.mahadasyam@sony.com>
Acked-by: Waiman Long <longman@redhat.com>
Acked-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Shashank Balaji 2025-03-05 13:12:43 +09:00 committed by Tejun Heo
parent c4af66a95a
commit c7461cca91
1 changed files with 14 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
Documentation/admin-guide/cgroup-v2.rst
View File

@ -1075,15 +1075,20 @@ cpufreq governor about the minimum desired frequency which should always be
provided by a CPU, as well as the maximum desired frequency, which should not
be exceeded by a CPU.
WARNING: cgroup2 doesn't yet support control of realtime processes. For
a kernel built with the CONFIG_RT_GROUP_SCHED option enabled for group
scheduling of realtime processes, the cpu controller can only be enabled
when all RT processes are in the root cgroup. This limitation does
not apply if CONFIG_RT_GROUP_SCHED is disabled. Be aware that system
management software may already have placed RT processes into nonroot
cgroups during the system boot process, and these processes may need
to be moved to the root cgroup before the cpu controller can be enabled
with a CONFIG_RT_GROUP_SCHED enabled kernel.
WARNING: cgroup2 cpu controller doesn't yet fully support the control of
realtime processes. For a kernel built with the CONFIG_RT_GROUP_SCHED option
enabled for group scheduling of realtime processes, the cpu controller can only
be enabled when all RT processes are in the root cgroup. Be aware that system
management software may already have placed RT processes into non-root cgroups
during the system boot process, and these processes may need to be moved to the
root cgroup before the cpu controller can be enabled with a
CONFIG_RT_GROUP_SCHED enabled kernel.
With CONFIG_RT_GROUP_SCHED disabled, this limitation does not apply and some of
the interface files either affect realtime processes or account for them. See
the following section for details. Only the cpu controller is affected by
CONFIG_RT_GROUP_SCHED. Other controllers can be used for the resource control of
realtime processes irrespective of CONFIG_RT_GROUP_SCHED.
CPU Interface Files