From 298f884a265c1c4b30cce7467650cc4a165a284e Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Tue, 5 Nov 2013 22:14:52 +0100

Subject: [PATCH] cgroup: run PID 1 in the root cgroup

This way cleaning up the cgroup tree on shutdown is a lot easier since

we are in the root dir. Also PID 1 was previously artificially placed in

system.slice, even though our rule actually was not to have processes in

slices. The root slice otoh is magic anyway, so having PID 1 in there

sounds less surprising.

Of course, this means that PID is scheduled against the three top-level

slices.

---

 src/core/cgroup.c | 16 ++++++++--------

 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/core/cgroup.c b/src/core/cgroup.c

index 8bf4d89..42c0b3f 100644

--- a/src/core/cgroup.c

+++ b/src/core/cgroup.c

@@ -589,8 +589,8 @@ pid_t unit_search_main_pid(Unit *u) {

 int manager_setup_cgroup(Manager *m) {

         _cleanup_free_ char *path = NULL;

+        char *e;

         int r;

-        char *e, *a;

         assert(m);

@@ -610,9 +610,13 @@ int manager_setup_cgroup(Manager *m) {

                 return r;

         }

-        /* Already in /system.slice? If so, let's cut this off again */

+        /* LEGACY: Already in /system.slice? If so, let's cut this

+         * off. This is to support live upgrades from older systemd

+         * versions where PID 1 was moved there. */

         if (m->running_as == SYSTEMD_SYSTEM) {

                 e = endswith(m->cgroup_root, "/" SPECIAL_SYSTEM_SLICE);

+                if (!e)

+                        e = endswith(m->cgroup_root, "/system");

                 if (e)

                         *e = 0;

         }

@@ -643,12 +647,8 @@ int manager_setup_cgroup(Manager *m) {

                         log_debug("Release agent already installed.");

         }

-        /* 4. Realize the system slice and put us in there */

-        if (m->running_as == SYSTEMD_SYSTEM) {

-                a = strappenda(m->cgroup_root, "/" SPECIAL_SYSTEM_SLICE);

-                r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, a, 0);

-        } else

-                r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, 0);

+        /* 4. Make sure we are in the root cgroup */

+        r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, 0);

         if (r < 0) {

                 log_error("Failed to create root cgroup hierarchy: %s", strerror(-r));

                 return r;