Move parent task to cgroup before other tasks are spawned

In addition to moving crosvm threads, move the parent spawning process before forks/execs occur. This ensures that vCPU threads get exclusive pCPU access. Bug: 408290580 Test: m && adb reboot and saw all threads moved

Author: daidavid1

base/cvd/cuttlefish/host/commands/run_cvd/boot_state_machine.cc

@@ -55,6 +55,19 @@ DEFINE_int32(reboot_notification_fd, CF_DEFAULTS_REBOOT_NOTIFICATION_FD,
 namespace cuttlefish {
 namespace {
 
+Result<void> MoveSelfToCgroup(const std::string& id) {
+ auto to_path_file = "/sys/fs/cgroup/vsoc-" + id + "-cf/cgroup.procs";
+ auto pid = std::to_string(getpid());
+ SharedFD fd = SharedFD::Open(to_path_file, O_WRONLY | O_APPEND);
+ CF_EXPECT(fd->IsOpen(),
+ "failed to open " << to_path_file << ": " << fd->StrError());
+ if (WriteAll(fd, pid) != pid.size()) {
+ return CF_ERR("failed to write to" << to_path_file);
+ }
+
+ return {};
+}
+
 Result<void> MoveThreadsToCgroup(const std::string& from_path,
  const std::string& to_path) {
  std::string file_path = from_path + "/cgroup.threads";
@@ -210,6 +223,12 @@ Result<SharedFD> ProcessLeader(
  CF_EXPECT(SharedFD::Fifo(instance.restore_adbd_pipe_name(), 0600),
  "Unable to create adbd restore fifo");
  }
+
+ // Move to designated cgroup path when running with vcpufreq enabled.
+ if (!instance.vcpu_config_path().empty()) {
+ CF_EXPECT(MoveSelfToCgroup(instance.id()));
+ }
+
  /* These two paths result in pretty different process state, but both
  * achieve the same goal of making the current process the leader of a
  * process group, and are therefore grouped together. */