core: don't use the unified hierarchy for the elogind cgroup yet (#4628)

Too many things don't get along with the unified hierarchy yet:

 * https://github.com/opencontainers/runc/issues/1175
 * https://github.com/docker/docker/issues/28109
 * https://github.com/lxc/lxc/issues/1280

So revert the default to the legacy hierarchy for now. Developers of the above
software can opt into the unified hierarchy with
"elogind.legacy_elogind_cgroup_controller=0".

diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index b95d70a1879e33f6526ef18a0c78a1b2d303c255..d499da1dc941fc68a01f4ac7bc18ffa6ee8408e6 100644 (file)
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -2489,10 +2489,10 @@ bool cg_is_unified_systemd_controller_wanted(void) {
 
                 r = get_proc_cmdline_key("systemd.legacy_systemd_cgroup_controller=", &value);
                 if (r < 0)
-                        return true;
+                        return false;
 
                 if (r == 0)
-                        wanted = true;
+                        wanted = false;
                 else
                         wanted = parse_boolean(value) <= 0;
         }