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

…ple instances in parallel TODO: cleanup_crash.sh
CTU-IIG · Apr 26, 2021 · b0e6dc2 · b0e6dc2
1 parent 6e63922
commit b0e6dc2
Showing 1 changed file with 8 additions and 4 deletions.
diff --git a/src/main.cpp b/src/main.cpp
@@ -12,7 +12,7 @@
 
 using namespace std;
 
-static string opt_demos_cg_name = "demos";
+static const string CGROUP_NAME_PREFIX = "demos-";
 
 static void handle_cgroup_exc(stringstream &commands,
                               stringstream &mount_cmds,
@@ -207,7 +207,8 @@ static void print_help()
     cout << "Usage: demos-sched -c <CONFIG_FILE> [-h] [-g <CGROUP_NAME>]\n"
             "  -c <CONFIG_FILE>    path to configuration file\n"
             "  -C <CONFIG>         inline configuration in YAML format\n"
-            "  -g <CGROUP_NAME>    name of root cgroups, default \"" << opt_demos_cg_name << "\"\n"
+            "  -g <CGROUP_NAME>    name of root cgroups, default \"" << CGROUP_NAME_PREFIX << "<process_pid>\"\n"
+            "                       NOTE: this name must be unique for each running instance of DEmOS\n"
             "  -m <WINDOW_MESSAGE> print the passed message to stdout at the beginning of each window;\n"
             "                       this may be useful for external synchronization with scheduler windows\n"
             "  -s                  rerun itself via systemd-run to get access to unified cgroup hierarchy\n"
@@ -227,11 +228,14 @@ int main(int argc, char *argv[])
     string config_file, config_str, window_sync_message;
     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, "dhgm:c:C:s")) != -1) {
         switch (opt) {
             case 'g': // custom root cgroup name
-                opt_demos_cg_name = optarg;
+                root_cgroup_name = optarg;
                 break;
             case 'c': // config file path
                 config_file = optarg;
@@ -293,7 +297,7 @@ int main(int argc, char *argv[])
 
         // set up demos container cgroups
         Cgroup unified_root, freezer_root, cpuset_root;
-        create_toplevel_cgroups(unified_root, freezer_root, cpuset_root, opt_demos_cg_name);
+        create_toplevel_cgroups(unified_root, freezer_root, cpuset_root, root_cgroup_name);
         logger->debug("Top level cgroups created");
 
         // select power policy