| // Copyright 2021 The Bazel Authors. All rights reserved. |
| // |
| // 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.google.devtools.build.lib.platform; |
| |
| import com.google.common.flogger.GoogleLogger; |
| import com.google.devtools.build.lib.events.Reporter; |
| import com.google.devtools.build.lib.jni.JniLoader; |
| import javax.annotation.Nullable; |
| import javax.annotation.concurrent.GuardedBy; |
| |
| /** A singleton that is the java side interface for dealing with memory pressure events. */ |
| public final class SystemMemoryPressureMonitor { |
| private static final GoogleLogger logger = GoogleLogger.forEnclosingClass(); |
| |
| private static final SystemMemoryPressureMonitor singleton = new SystemMemoryPressureMonitor(); |
| |
| @GuardedBy("this") |
| @Nullable |
| private Reporter reporter; |
| |
| public static SystemMemoryPressureMonitor getInstance() { |
| return singleton; |
| } |
| |
| private SystemMemoryPressureMonitor() { |
| JniLoader.loadJni(); |
| if (JniLoader.isJniAvailable()) { |
| registerJNI(); |
| } |
| } |
| |
| private native void registerJNI(); |
| |
| private native int systemMemoryPressure(); |
| |
| /** The possible memory pressure levels. */ |
| public enum Level { |
| NORMAL("Normal"), |
| WARNING("Warning"), |
| CRITICAL("Critical"); |
| |
| private final String logString; |
| |
| Level(String logString) { |
| this.logString = logString; |
| } |
| |
| public String logString() { |
| return logString; |
| } |
| |
| /** These constants are mapped to enum in third_party/bazel/src/main/native/unix_jni.h. */ |
| static Level fromInt(int number) { |
| switch (number) { |
| case 0: |
| return NORMAL; |
| case 1: |
| return WARNING; |
| case 2: |
| return CRITICAL; |
| default: |
| throw new IllegalStateException("Unknown memory pressure level: " + number); |
| } |
| } |
| }; |
| |
| /** Return current memory pressure */ |
| public Level level() { |
| return Level.fromInt(systemMemoryPressure()); |
| } |
| |
| public synchronized void setReporter(@Nullable Reporter reporter) { |
| this.reporter = reporter; |
| int pressure = systemMemoryPressure(); |
| if (Level.fromInt(pressure) != Level.NORMAL) { |
| memoryPressureCallback(pressure); |
| } |
| } |
| |
| synchronized void memoryPressureCallback(int value) { |
| SystemMemoryPressureEvent event = new SystemMemoryPressureEvent(Level.fromInt(value)); |
| if (reporter != null) { |
| reporter.post(event); |
| } |
| logger.atInfo().log("%s", event.logString()); |
| } |
| } |