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//
// 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.
//
#ifndef UPDATE_ENGINE_COMMON_CPU_LIMITER_H_
#define UPDATE_ENGINE_COMMON_CPU_LIMITER_H_
#include <brillo/message_loops/message_loop.h>
namespace chromeos_update_engine {
// Cgroups cpu shares constants. 1024 is the default shares a standard process
// gets and 2 is the minimum value. We set High as a value that gives the
// update-engine 2x the cpu share of a standard process.
enum class CpuShares : int {
kHigh = 2048,
kNormal = 1024,
kLow = 2,
};
class CPULimiter {
public:
CPULimiter() = default;
~CPULimiter();
// Sets the cpu shares to low and sets up timeout events to stop the limiter.
void StartLimiter();
// Resets the cpu shares to normal and destroys any scheduled timeout sources.
void StopLimiter();
// Sets the cpu shares to |shares|. This method can be user at any time, but
// if the limiter is not running, the shares won't be reset to normal.
bool SetCpuShares(CpuShares shares);
private:
// The cpu shares timeout source callback sets the current cpu shares to
// normal.
void StopLimiterCallback();
// Current cpu shares.
CpuShares shares_ = CpuShares::kNormal;
// The cpu shares management timeout task id.
brillo::MessageLoop::TaskId manage_shares_id_{
brillo::MessageLoop::kTaskIdNull};
};
} // namespace chromeos_update_engine
#endif // UPDATE_ENGINE_COMMON_CPU_LIMITER_H_