/*
* Copyright 2016 the original author or authors.
*
* 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 org.gradle.process.internal.health.memory;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import org.gradle.internal.concurrent.ExecutorFactory;
import org.gradle.internal.concurrent.Stoppable;
import org.gradle.internal.concurrent.StoppableScheduledExecutor;
import org.gradle.internal.event.ListenerManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
public class DefaultMemoryManager implements MemoryManager, Stoppable {
private static final Logger LOGGER = LoggerFactory.getLogger(MemoryManager.class);
public static final int STATUS_INTERVAL_SECONDS = 5;
private static final double DEFAULT_MIN_FREE_MEMORY_PERCENTAGE = 0.1D; // 10%
private static final long MIN_THRESHOLD_BYTES = 384 * 1024 * 1024; // 384M
private final double minFreeMemoryPercentage;
private final OsMemoryInfo osMemoryInfo;
private final JvmMemoryInfo jvmMemoryInfo;
private final ListenerManager listenerManager;
private final StoppableScheduledExecutor scheduler;
private final JvmMemoryStatusListener jvmBroadcast;
private final OsMemoryStatusListener osBroadcast;
private final boolean osMemoryStatusSupported;
private final Object holdersLock = new Object();
private final Object memoryLock = new Object();
private final List<MemoryHolder> holders = new ArrayList<MemoryHolder>();
private OsMemoryStatus currentOsMemoryStatus;
private final OsMemoryStatusListener osMemoryStatusListener;
public DefaultMemoryManager(OsMemoryInfo osMemoryInfo, JvmMemoryInfo jvmMemoryInfo, ListenerManager listenerManager, ExecutorFactory executorFactory) {
this(osMemoryInfo, jvmMemoryInfo, listenerManager, executorFactory, DEFAULT_MIN_FREE_MEMORY_PERCENTAGE, true);
}
@VisibleForTesting
DefaultMemoryManager(OsMemoryInfo osMemoryInfo, JvmMemoryInfo jvmMemoryInfo, ListenerManager listenerManager, ExecutorFactory executorFactory, double minFreeMemoryPercentage, boolean autoFree) {
Preconditions.checkArgument(minFreeMemoryPercentage >= 0, "Free memory percentage must be >= 0");
Preconditions.checkArgument(minFreeMemoryPercentage <= 1, "Free memory percentage must be <= 1");
this.minFreeMemoryPercentage = minFreeMemoryPercentage;
this.osMemoryInfo = osMemoryInfo;
this.jvmMemoryInfo = jvmMemoryInfo;
this.listenerManager = listenerManager;
this.scheduler = executorFactory.createScheduled("Memory manager", 1);
this.jvmBroadcast = listenerManager.getBroadcaster(JvmMemoryStatusListener.class);
this.osBroadcast = listenerManager.getBroadcaster(OsMemoryStatusListener.class);
this.osMemoryStatusSupported = supportsOsMemoryStatus();
this.osMemoryStatusListener = new OsMemoryListener(autoFree);
start();
}
private boolean supportsOsMemoryStatus() {
try {
osMemoryInfo.getOsSnapshot();
return true;
} catch (UnsupportedOperationException ex) {
return false;
}
}
private void start() {
scheduler.scheduleAtFixedRate(new MemoryCheck(), STATUS_INTERVAL_SECONDS, STATUS_INTERVAL_SECONDS, TimeUnit.SECONDS);
LOGGER.debug("Memory status broadcaster started");
if (osMemoryStatusSupported) {
addListener(osMemoryStatusListener);
} else {
LOGGER.info("This JVM does not support getting OS memory, so no OS memory status updates will be broadcast");
}
}
@Override
public void stop() {
scheduler.stop();
listenerManager.removeListener(osMemoryStatusListener);
}
@Override
public void requestFreeMemory(long memoryAmountBytes) {
synchronized (memoryLock) {
if (currentOsMemoryStatus != null) {
long totalPhysicalMemory = currentOsMemoryStatus.getTotalPhysicalMemory();
long requestedFreeMemory = getMemoryThresholdInBytes(totalPhysicalMemory) + (memoryAmountBytes > 0 ? memoryAmountBytes : 0);
long freeMemory = currentOsMemoryStatus.getFreePhysicalMemory();
long newFreeMemory = doRequestFreeMemory(requestedFreeMemory, freeMemory);
// If we've freed memory, invalidate the current OS memory snapshot
if (newFreeMemory > freeMemory) {
currentOsMemoryStatus = null;
}
} else {
LOGGER.debug("There is no current snapshot of OS memory available - memory cannot be freed until a new memory status update occurs");
}
}
}
private long doRequestFreeMemory(long requestedFreeMemory, long freeMemory) {
long toReleaseMemory = requestedFreeMemory;
if (freeMemory < requestedFreeMemory) {
LOGGER.debug("{} memory requested, {} free", requestedFreeMemory, freeMemory);
synchronized (holdersLock) {
for (MemoryHolder holder : holders) {
long released = holder.attemptToRelease(toReleaseMemory);
toReleaseMemory -= released;
freeMemory += released;
if (freeMemory >= requestedFreeMemory) {
break;
}
}
}
LOGGER.debug("{} memory requested, {} released, {} free", requestedFreeMemory, requestedFreeMemory - toReleaseMemory, freeMemory);
}
return freeMemory;
}
private long getMemoryThresholdInBytes(long totalPhysicalMemory) {
return Math.max(MIN_THRESHOLD_BYTES, (long) (totalPhysicalMemory * minFreeMemoryPercentage));
}
private class MemoryCheck implements Runnable {
@Override
public void run() {
try {
if (osMemoryStatusSupported) {
OsMemoryStatus os = osMemoryInfo.getOsSnapshot();
LOGGER.debug("Emitting OS memory status event {}", os);
osBroadcast.onOsMemoryStatus(os);
}
JvmMemoryStatus jvm = jvmMemoryInfo.getJvmSnapshot();
LOGGER.debug("Emitting JVM memory status event {}", jvm);
jvmBroadcast.onJvmMemoryStatus(jvm);
} catch (Exception ex) {
LOGGER.debug("Failed to collect memory status: {}", ex.getMessage(), ex);
}
}
}
private class OsMemoryListener implements OsMemoryStatusListener {
private final boolean autoFree;
private OsMemoryListener(boolean autoFree) {
this.autoFree = autoFree;
}
@Override
public void onOsMemoryStatus(OsMemoryStatus os) {
currentOsMemoryStatus = os;
if (autoFree) {
requestFreeMemory(0);
}
}
}
@Override
public void addMemoryHolder(MemoryHolder holder) {
holders.add(holder);
}
@Override
public void removeMemoryHolder(MemoryHolder holder) {
holders.remove(holder);
}
@Override
public void addListener(JvmMemoryStatusListener listener) {
listenerManager.addListener(listener);
}
@Override
public void addListener(OsMemoryStatusListener listener) {
listenerManager.addListener(listener);
}
@Override
public void removeListener(JvmMemoryStatusListener listener) {
listenerManager.removeListener(listener);
}
@Override
public void removeListener(OsMemoryStatusListener listener) {
listenerManager.removeListener(listener);
}
}