#31 Suffix cgroup names with DEmOS process PID to allow running multi…

…ple instances in parallel

TODO: cleanup_crash.sh

src/main.cpp

@@ -6,7 +6,7 @@
 
 using namespace std;
 
-static string opt_demos_cg_name = "demos";
+static const string CGROUP_NAME_PREFIX = "demos-";
 
 static string pluralize(unsigned long count, const string &noun)
 {
@@ -78,6 +78,9 @@ int main(int argc, char *argv[])
     string config_file, config_str, window_sync_message, mf_sync_message, power_policy_name;
     bool dump_config = false;
     bool systemd_run = false;
+    // to support multiple instances of DEmOS running at once (primarily for testing),
+    //  default root cgroup name includes the scheduler process PID
+    string root_cgroup_name = CGROUP_NAME_PREFIX + to_string(getpid());
 
     while ((opt = getopt(argc, argv, "c:C:p:g:m:M:sdh")) != -1) {
         switch (opt) {
@@ -91,7 +94,7 @@ int main(int argc, char *argv[])
                 power_policy_name = optarg;
                 break;
             case 'g': // custom root cgroup name
-                opt_demos_cg_name = optarg;
+                root_cgroup_name = optarg;
                 break;
             case 'm': // window start sync message
                 window_sync_message = optarg;
@@ -154,7 +157,7 @@ int main(int argc, char *argv[])
         logger->trace("Creating top-level cgroups");
         Cgroup unified_root, freezer_root, cpuset_root;
         if (!cgroup_setup::create_toplevel_cgroups(
-              unified_root, freezer_root, cpuset_root, opt_demos_cg_name)) {
+              unified_root, freezer_root, cpuset_root, root_cgroup_name)) {
             // cgroup creation failed
             return 1;
         }