| /* |
| * Copyright (C) 2020 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. |
| */ |
| |
| package com.android.server; |
| |
| import android.os.StrictMode; |
| import android.util.Slog; |
| |
| import libcore.io.IoUtils; |
| |
| import java.io.File; |
| import java.io.IOException; |
| import java.io.StringWriter; |
| import java.util.Arrays; |
| import java.util.List; |
| |
| /** |
| * Utility method for resource pressure (PSI). |
| */ |
| public final class ResourcePressureUtil { |
| |
| private static final String PSI_ROOT = "/proc/pressure"; |
| private static final String TAG = "ResourcePressureUtil"; |
| private static final List<String> PSI_FILES = Arrays.asList( |
| PSI_ROOT + "/memory", |
| PSI_ROOT + "/cpu", |
| PSI_ROOT + "/io" |
| ); |
| |
| private static String readResourcePsiState(String filePath) { |
| StringWriter contents = new StringWriter(); |
| try { |
| if (new File(filePath).exists()) { |
| contents.append("----- Output from " + filePath + " -----\n"); |
| contents.append(IoUtils.readFileAsString(filePath)); |
| contents.append("----- End output from " + filePath + " -----\n"); |
| } |
| } catch (IOException e) { |
| Slog.e(TAG, " could not read " + filePath, e); |
| } |
| return contents.toString(); |
| } |
| |
| /** |
| * @return a stanza about PSI to add to a report. |
| */ |
| public static String currentPsiState() { |
| final StrictMode.ThreadPolicy savedPolicy = StrictMode.allowThreadDiskReads(); |
| StringWriter aggregatedState = new StringWriter(); |
| |
| try { |
| PSI_FILES.stream() |
| .map(ResourcePressureUtil::readResourcePsiState) |
| .forEach(aggregatedState::append); |
| } finally { |
| StrictMode.setThreadPolicy(savedPolicy); |
| } |
| |
| String psiState = aggregatedState.toString(); |
| |
| return psiState.length() > 0 ? psiState + "\n" : psiState; |
| } |
| |
| private ResourcePressureUtil(){} |
| } |