diff --git a/Documentation/admin-guide/cgroup-v1/cpusets.rst b/Documentation/admin-guide/cgroup-v1/cpusets.rst
index ae646d621a8a..7d3415eea05d 100644
--- a/Documentation/admin-guide/cgroup-v1/cpusets.rst
+++ b/Documentation/admin-guide/cgroup-v1/cpusets.rst
@@ -179,7 +179,7 @@ files describing that cpuset:
  - cpuset.mem_hardwall flag:  is memory allocation hardwalled
  - cpuset.memory_pressure: measure of how much paging pressure in cpuset
  - cpuset.memory_spread_page flag: if set, spread page cache evenly on allowed nodes
- - cpuset.memory_spread_slab flag: if set, spread slab cache evenly on allowed nodes
+ - cpuset.memory_spread_slab flag: OBSOLETE. Doesn't have any function.
  - cpuset.sched_load_balance flag: if set, load balance within CPUs on that cpuset
  - cpuset.sched_relax_domain_level: the searching range when migrating tasks
 
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index ba36c073304a..c940cf01b148 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -3897,6 +3897,7 @@ static struct cftype legacy_files[] = {
 	},
 
 	{
+		/* obsolete, may be removed in the future */
 		.name = "memory_spread_slab",
 		.read_u64 = cpuset_read_u64,
 		.write_u64 = cpuset_write_u64,