[PATCH v2 3/3] docs: cgroup-v1: clarify that domain levels are system-specific

[Vitalii Bursov]

Add a clarification that domain levels are system-specific
and where to check for system details.

Add CPU clusters to the scheduler domain levels table.

Signed-off-by: Vitalii Bursov <vitaly@xxxxxxxxxx>
---
 Documentation/admin-guide/cgroup-v1/cpusets.rst | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/Documentation/admin-guide/cgroup-v1/cpusets.rst b/Documentation/admin-guide/cgroup-v1/cpusets.rst
index 7d3415eea..d16a3967d 100644
--- a/Documentation/admin-guide/cgroup-v1/cpusets.rst
+++ b/Documentation/admin-guide/cgroup-v1/cpusets.rst
@@ -568,19 +568,25 @@ on the next tick.  For some applications in special situation, waiting
 
 The 'cpuset.sched_relax_domain_level' file allows you to request changing
 this searching range as you like.  This file takes int value which
-indicates size of searching range in levels ideally as follows,
+indicates size of searching range in levels approximately as follows,
 otherwise initial value -1 that indicates the cpuset has no request.
 
 ====== ===========================================================
   -1   no request. use system default or follow request of others.
    0   no search.
    1   search siblings (hyperthreads in a core).
-   2   search cores in a package.
-   3   search cpus in a node [= system wide on non-NUMA system]
-   4   search nodes in a chunk of node [on NUMA system]
-   5   search system wide [on NUMA system]
+   2   search cpu clusters
+   3   search cores in a package.
+   4   search cpus in a node [= system wide on non-NUMA system]
+   5   search nodes in a chunk of node [on NUMA system]
+   6   search system wide [on NUMA system]
 ====== ===========================================================
 
+Not all levels can be present and values can change depending on the
+system architecture and kernel configuration. Check
+/sys/kernel/debug/sched/domains/cpu*/domain*/ for system-specific
+details.
+
 The system default is architecture dependent.  The system default
 can be changed using the relax_domain_level= boot parameter.
 
-- 
2.20.1