Revert "Use mem cgroups in libprocessgroup if they're available"

This reverts commit 32375c2328.

bug 63164307

Change-Id: I3336bbf7c2f3297b231c5b0a1ef538faff9513fd

libprocessgroup/processgroup.cpp

@@ -43,6 +43,9 @@
 
 using namespace std::chrono_literals;
 
+// Uncomment line below use memory cgroups for keeping track of (forked) PIDs
+// #define USE_MEMCG 1
+
 #define MEM_CGROUP_PATH "/dev/memcg/apps"
 #define MEM_CGROUP_TASKS "/dev/memcg/apps/tasks"
 #define ACCT_CGROUP_PATH "/acct"
@@ -88,6 +91,7 @@ class ProcessGroup {
 };
 
 static const char* getCgroupRootPath() {
+#ifdef USE_MEMCG
     static const char* cgroup_root_path = NULL;
     std::call_once(init_path_flag, [&]() {
             // Check if mem cgroup is mounted, only then check for write-access to avoid
@@ -96,6 +100,9 @@ static const char* getCgroupRootPath() {
                     ACCT_CGROUP_PATH : MEM_CGROUP_PATH;
             });
     return cgroup_root_path;
+#else
+    return ACCT_CGROUP_PATH;
+#endif
 }
 
 static int convertUidToPath(char *path, size_t size, uid_t uid)

rootdir/init.rc

@@ -36,8 +36,6 @@ on early-init
     mount cgroup none /dev/memcg memory
     # app mem cgroups, used by activity manager, lmkd and zygote
     mkdir /dev/memcg/apps/ 0755 system system
-    # cgroup for system_server and surfaceflinger
-    mkdir /dev/memcg/system 0755 system system
 
     start ueventd