1 // 2 // Copyright (C) 2016 The Android Open Source Project 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 17 #ifndef UPDATE_ENGINE_COMMON_CPU_LIMITER_H_ 18 #define UPDATE_ENGINE_COMMON_CPU_LIMITER_H_ 19 20 #include <brillo/message_loops/message_loop.h> 21 22 namespace chromeos_update_engine { 23 24 // Cgroups cpu shares constants. 1024 is the default shares a standard process 25 // gets and 2 is the minimum value. We set High as a value that gives the 26 // update-engine 2x the cpu share of a standard process. 27 enum class CpuShares : int { 28 kHigh = 2048, 29 kNormal = 1024, 30 kLow = 2, 31 }; 32 33 class CPULimiter { 34 public: 35 CPULimiter() = default; 36 ~CPULimiter(); 37 38 // Sets the cpu shares to low and sets up timeout events to stop the limiter. 39 void StartLimiter(); 40 41 // Resets the cpu shares to normal and destroys any scheduled timeout sources. 42 void StopLimiter(); 43 44 // Sets the cpu shares to |shares|. This method can be user at any time, but 45 // if the limiter is not running, the shares won't be reset to normal. 46 bool SetCpuShares(CpuShares shares); 47 48 private: 49 // The cpu shares timeout source callback sets the current cpu shares to 50 // normal. 51 void StopLimiterCallback(); 52 53 // Current cpu shares. 54 CpuShares shares_ = CpuShares::kNormal; 55 56 // The cpu shares management timeout task id. 57 brillo::MessageLoop::TaskId manage_shares_id_{ 58 brillo::MessageLoop::kTaskIdNull}; 59 }; 60 61 } // namespace chromeos_update_engine 62 63 #endif // UPDATE_ENGINE_COMMON_CPU_LIMITER_H_ 64