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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.
//
#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::NumberToString(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 = " << static_cast<int>(shares_);
return true;
}
void CPULimiter::StopLimiterCallback() {
SetCpuShares(CpuShares::kNormal);
manage_shares_id_ = brillo::MessageLoop::kTaskIdNull;
}
} // namespace chromeos_update_engine