| /* |
| * Copyright (C) 2017 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 specic language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #define LOG_TAG "libperfmgr" |
| |
| #include <android-base/file.h> |
| #include <android-base/logging.h> |
| #include <android-base/stringprintf.h> |
| #include <android-base/strings.h> |
| |
| #include "perfmgr/FileNode.h" |
| |
| namespace android { |
| namespace perfmgr { |
| |
| FileNode::FileNode(std::string name, std::string node_path, |
| std::vector<RequestGroup> req_sorted, |
| std::size_t default_val_index, bool reset_on_init, |
| bool hold_fd) |
| : Node(std::move(name), std::move(node_path), std::move(req_sorted), |
| default_val_index, reset_on_init), |
| hold_fd_(hold_fd) { |
| if (reset_on_init) { |
| Update(false); |
| } |
| } |
| |
| std::chrono::milliseconds FileNode::Update(bool log_error) { |
| std::size_t value_index = default_val_index_; |
| std::chrono::milliseconds expire_time = std::chrono::milliseconds::max(); |
| |
| // Find the highest outstanding request's expire time |
| for (std::size_t i = 0; i < req_sorted_.size(); i++) { |
| if (req_sorted_[i].GetExpireTime(&expire_time)) { |
| value_index = i; |
| break; |
| } |
| } |
| |
| // Update node only if request index changes |
| if (value_index != current_val_index_) { |
| const std::string& req_value = |
| req_sorted_[value_index].GetRequestValue(); |
| |
| fd_.reset(TEMP_FAILURE_RETRY( |
| open(node_path_.c_str(), O_WRONLY | O_CLOEXEC | O_TRUNC))); |
| |
| if (fd_ == -1 || !android::base::WriteStringToFd(req_value, fd_)) { |
| if (log_error) { |
| LOG(WARNING) << "Failed to write to node: " << node_path_ |
| << " with value: " << req_value << ", fd: " << fd_; |
| } |
| // Retry in 500ms or sooner |
| expire_time = std::min(expire_time, std::chrono::milliseconds(500)); |
| } else { |
| // For regular file system, we need fsync |
| fsync(fd_); |
| // Some dev node requires file to remain open during the entire hint |
| // duration e.g. /dev/cpu_dma_latency, so fd_ is intentionally kept |
| // open during any requested value other than default one. If |
| // request a default value, node will write the value and then |
| // release the fd. |
| if ((!hold_fd_) || value_index == default_val_index_) { |
| fd_.reset(); |
| } |
| // Update current index only when succeed |
| current_val_index_ = value_index; |
| } |
| } |
| return expire_time; |
| } |
| |
| bool FileNode::GetHoldFd() const { |
| return hold_fd_; |
| } |
| |
| void FileNode::DumpToFd(int fd) const { |
| std::string node_value; |
| if (!android::base::ReadFileToString(node_path_, &node_value)) { |
| LOG(ERROR) << "Failed to read node path: " << node_path_; |
| } |
| node_value = android::base::Trim(node_value); |
| std::string buf(android::base::StringPrintf( |
| "%s\t%s\t%zu\t%s\n", name_.c_str(), node_path_.c_str(), |
| current_val_index_, node_value.c_str())); |
| if (!android::base::WriteStringToFd(buf, fd)) { |
| LOG(ERROR) << "Failed to dump fd: " << fd; |
| } |
| } |
| |
| } // namespace perfmgr |
| } // namespace android |