Add support for freezer cgroup

Adds the freezer cgroup to process groups

Change-Id: Ib7a8dbe776ff156ff3827b9a659365384f3e6ac8
Bug: 143308662
Test: manual - frozen processes aren't scheduled for execution until
unfrozen

libprocessgroup/profiles/cgroups.json

@@ -39,6 +39,13 @@
       "Mode": "0755",
       "UID": "system",
       "GID": "system"
+    },
+    {
+      "Controller": "freezer",
+      "Path": "/dev/freezer",
+      "Mode": "0755",
+      "UID": "system",
+      "GID": "system"
     }
   ],
   "Cgroups2": {

libprocessgroup/profiles/task_profiles.json

@@ -66,6 +66,32 @@
         }
       ]
     },
+    {
+      "Name": "Frozen",
+      "Actions": [
+        {
+          "Name": "JoinCgroup",
+          "Params":
+          {
+            "Controller": "freezer",
+            "Path": "frozen"
+          }
+        }
+      ]
+    },
+    {
+      "Name": "Unfrozen",
+      "Actions": [
+        {
+          "Name": "JoinCgroup",
+          "Params":
+          {
+            "Controller": "freezer",
+            "Path": ""
+          }
+        }
+      ]
+    },
     {
       "Name": "NormalPerformance",
       "Actions": [

rootdir/init.rc

@@ -283,6 +283,16 @@ on init
     chmod 0664 /dev/cpuset/restricted/tasks
     chmod 0664 /dev/cpuset/tasks
 
+    # freezer cgroup entries
+    mkdir /dev/freezer/frozen
+    write /dev/freezer/frozen/freezer.state FROZEN
+    chown system system /dev/freezer/cgroup.procs
+    chown system system /dev/freezer/frozen
+    chown system system /dev/freezer/frozen/freezer.state
+    chown system system /dev/freezer/frozen/cgroup.procs
+
+    chmod 0444 /dev/freezer/frozen/freezer.state
+
     # make the PSI monitor accessible to others
     chown system system /proc/pressure/memory
     chmod 0664 /proc/pressure/memory