cgroup: extend cg_mask_supported() comment a bit

diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index d38452cfcbb8ed33798fedfb8e04fddcb262bcdc..3f94602c8f0f585b9a1f8b05aa813ec5a1ae1d6b 100644 (file)
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -2368,9 +2368,9 @@ int cg_mask_supported(CGroupMask *ret) {
         CGroupMask mask;
         int r;
 
-        /* Determines the mask of supported cgroup controllers. Only
-         * includes controllers we can make sense of and that are
-         * actually accessible. */
+        /* Determines the mask of supported cgroup controllers. Only includes controllers we can make sense of and that
+         * are actually accessible. Only covers real controllers, i.e. not the CGROUP_CONTROLLER_BPF_xyz
+         * pseudo-controllers. */
 
         r = cg_all_unified();
         if (r < 0)