diff --git a/common/cpu_limiter.cc b/common/cpu_limiter.cc
new file mode 100644
index 0000000..67c50b6
--- /dev/null
+++ b/common/cpu_limiter.cc
@@ -0,0 +1,88 @@
+//
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#include "update_engine/common/cpu_limiter.h"
+
+#include <string>
+
+#include <base/bind.h>
+#include <base/logging.h>
+#include <base/strings/string_number_conversions.h>
+#include <base/time/time.h>
+
+#include "update_engine/common/utils.h"
+
+namespace {
+
+// Cgroup container is created in update-engine's upstart script located at
+// /etc/init/update-engine.conf.
+const char kCGroupSharesPath[] = "/sys/fs/cgroup/cpu/update-engine/cpu.shares";
+
+}  // namespace
+
+namespace chromeos_update_engine {
+
+CPULimiter::~CPULimiter() {
+  // Set everything back to normal on destruction.
+  CPULimiter::SetCpuShares(CpuShares::kNormal);
+}
+
+void CPULimiter::StartLimiter() {
+  if (manage_shares_id_ != brillo::MessageLoop::kTaskIdNull) {
+    LOG(ERROR) << "Cpu shares timeout source hasn't been destroyed.";
+    StopLimiter();
+  }
+  manage_shares_id_ = brillo::MessageLoop::current()->PostDelayedTask(
+      FROM_HERE,
+      base::Bind(&CPULimiter::StopLimiterCallback, base::Unretained(this)),
+      base::TimeDelta::FromHours(2));
+  SetCpuShares(CpuShares::kLow);
+}
+
+void CPULimiter::StopLimiter() {
+  if (manage_shares_id_ != brillo::MessageLoop::kTaskIdNull) {
+    // If the shares were never set and there isn't a message loop instance,
+    // we avoid calling CancelTask(), which otherwise would have been a no-op.
+    brillo::MessageLoop::current()->CancelTask(manage_shares_id_);
+    manage_shares_id_ = brillo::MessageLoop::kTaskIdNull;
+  }
+  SetCpuShares(CpuShares::kNormal);
+}
+
+bool CPULimiter::SetCpuShares(CpuShares shares) {
+  // Short-circuit to avoid re-setting the shares.
+  if (shares_ == shares)
+    return true;
+
+  std::string string_shares = base::IntToString(static_cast<int>(shares));
+  LOG(INFO) << "Setting cgroup cpu shares to  " << string_shares;
+  if (!utils::WriteFile(
+          kCGroupSharesPath, string_shares.c_str(), string_shares.size())) {
+    LOG(ERROR) << "Failed to change cgroup cpu shares to " << string_shares
+               << " using " << kCGroupSharesPath;
+    return false;
+  }
+  shares_ = shares;
+  LOG(INFO) << "CPU shares = " << shares_;
+  return true;
+}
+
+void CPULimiter::StopLimiterCallback() {
+  SetCpuShares(CpuShares::kNormal);
+  manage_shares_id_ = brillo::MessageLoop::kTaskIdNull;
+}
+
+}  // namespace chromeos_update_engine