meson: drop default-hierarchy= option, always use unified

meson.build

@@ -761,17 +761,6 @@ if fallback_hostname == '' or fallback_hostname[0] == '.' or fallback_hostname[0
 endif
 conf.set_quoted('FALLBACK_HOSTNAME', fallback_hostname)
 
-default_hierarchy = get_option('default-hierarchy')
-conf.set_quoted('DEFAULT_HIERARCHY_NAME', default_hierarchy,
-                description : 'default cgroup hierarchy as string')
-if default_hierarchy == 'legacy'
-        conf.set('DEFAULT_HIERARCHY', 'CGROUP_UNIFIED_NONE')
-elif default_hierarchy == 'hybrid'
-        conf.set('DEFAULT_HIERARCHY', 'CGROUP_UNIFIED_SYSTEMD')
-else
-        conf.set('DEFAULT_HIERARCHY', 'CGROUP_UNIFIED_ALL')
-endif
-
 extra_net_naming_schemes = []
 extra_net_naming_map = []
 foreach scheme: get_option('extra-net-naming-schemes').split(',')
@@ -2768,7 +2757,6 @@ summary({
         'default LLMNR mode' :              default_llmnr,
         'default DNS servers' :             dns_servers.split(' '),
         'default NTP servers' :             ntp_servers.split(' '),
-        'default cgroup hierarchy' :        default_hierarchy,
         'default net.naming-scheme value' : default_net_naming_scheme,
         'default KillUserProcesses value' : kill_user_processes,
         'default locale' :                  default_locale,

meson_options.txt

@@ -227,8 +227,8 @@ option('configfiledir', type : 'string', value : '',
 option('fallback-hostname', type : 'string', value : 'localhost',
        description : 'the hostname used if none configured')
 option('default-hierarchy', type : 'combo',
-       choices : ['legacy', 'hybrid', 'unified'], value : 'unified',
-       description : 'default cgroup hierarchy')
+       choices : ['legacy', 'hybrid', 'unified'], deprecated : true,
+       description : '''This option is deprecated and will be removed in a future release''')
 option('extra-net-naming-schemes', type : 'string',
        description : 'comma-separated list of extra net.naming-scheme= definitions')
 option('default-net-naming-scheme', type : 'string', value : 'latest',

src/basic/build.c

@@ -244,7 +244,6 @@ const char* const systemd_features =
         " -LIBARCHIVE"
 #endif
 
-        " default-hierarchy=" DEFAULT_HIERARCHY_NAME
         ;
 
 static char *systemd_features_with_color(void) {

src/shared/cgroup-setup.c

@@ -81,9 +81,6 @@ static int cg_any_controller_used_for_v1(void) {
 
 bool cg_is_unified_wanted(void) {
         static thread_local int wanted = -1;
-        bool b;
-        const bool is_default = DEFAULT_HIERARCHY == CGROUP_UNIFIED_ALL;
-        _cleanup_free_ char *c = NULL;
         int r;
 
         /* If we have a cached value, return that. */
@@ -96,21 +93,20 @@ bool cg_is_unified_wanted(void) {
                 return (wanted = r >= CGROUP_UNIFIED_ALL);
 
         /* If we were explicitly passed systemd.unified_cgroup_hierarchy, respect that. */
+        bool b;
         r = proc_cmdline_get_bool("systemd.unified_cgroup_hierarchy", /* flags = */ 0, &b);
         if (r > 0)
                 return (wanted = b);
 
         /* If we passed cgroup_no_v1=all with no other instructions, it seems highly unlikely that we want to
          * use hybrid or legacy hierarchy. */
+        _cleanup_free_ char *c = NULL;
         r = proc_cmdline_get_key("cgroup_no_v1", 0, &c);
         if (r > 0 && streq_ptr(c, "all"))
                 return (wanted = true);
 
         /* If any controller is in use as v1, don't use unified. */
-        if (cg_any_controller_used_for_v1() > 0)
-                return (wanted = false);
-
-        return (wanted = is_default);
+        return (wanted = cg_any_controller_used_for_v1() <= 0);
 }
 
 bool cg_is_legacy_wanted(void) {
@@ -132,10 +128,6 @@ bool cg_is_legacy_wanted(void) {
 bool cg_is_hybrid_wanted(void) {
         static thread_local int wanted = -1;
         int r;
-        bool b;
-        const bool is_default = DEFAULT_HIERARCHY >= CGROUP_UNIFIED_SYSTEMD;
-        /* We default to true if the default is "hybrid", obviously, but also when the default is "unified",
-         * because if we get called, it means that unified hierarchy was not mounted. */
 
         /* If we have a cached value, return that. */
         if (wanted >= 0)
@@ -146,12 +138,17 @@ bool cg_is_hybrid_wanted(void) {
                 return (wanted = false);
 
         /* Otherwise, let's see what the kernel command line has to say.  Since checking is expensive, cache
-         * a non-error result. */
-        r = proc_cmdline_get_bool("systemd.legacy_systemd_cgroup_controller", /* flags = */ 0, &b);
-
-        /* The meaning of the kernel option is reversed wrt. to the return value of this function, hence the
+         * a non-error result.
+         * The meaning of the kernel option is reversed wrt. to the return value of this function, hence the
          * negation. */
-        return (wanted = r > 0 ? !b : is_default);
+        bool b;
+        r = proc_cmdline_get_bool("systemd.legacy_systemd_cgroup_controller", /* flags = */ 0, &b);
+        if (r > 0)
+                return (wanted = !b);
+
+        /* The default hierarchy is "unified". But if this is reached, it means that unified hierarchy was
+         * not mounted, so return true too. */
+        return (wanted = true);
 }
 
 bool cg_is_legacy_force_enabled(void) {

src/test/test-cgroup-setup.c

@@ -16,10 +16,8 @@ static void test_is_wanted_print_one(bool header) {
         log_info("-- %s --", __func__);
         assert_se(proc_cmdline(&cmdline) >= 0);
         log_info("cmdline: %s", cmdline);
-        if (header) {
-                log_info("default-hierarchy=" DEFAULT_HIERARCHY_NAME);
+        if (header)
                 (void) system("findmnt -n /sys/fs/cgroup");
-        }
 
         log_info("is_unified_wanted() → %s", yes_no(cg_is_unified_wanted()));
         log_info("is_hybrid_wanted() → %s", yes_no(cg_is_hybrid_wanted()));