package com.orientechnologies.orient.core;
import java.lang.management.ManagementFactory;
import java.lang.management.MemoryMXBean;
import java.lang.management.MemoryNotificationInfo;
import java.lang.management.MemoryPoolMXBean;
import java.lang.management.MemoryType;
import java.util.Collection;
import java.util.concurrent.CopyOnWriteArrayList;
import javax.management.Notification;
import javax.management.NotificationEmitter;
import javax.management.NotificationListener;
import com.orientechnologies.common.io.OFileUtils;
import com.orientechnologies.common.log.OLogManager;
import com.orientechnologies.common.profiler.OProfiler;
import com.orientechnologies.common.profiler.OProfiler.OProfilerHookValue;
import com.orientechnologies.orient.core.OMemoryWatchDog.Listener.TYPE;
import com.orientechnologies.orient.core.config.OGlobalConfiguration;
/**
* This memory warning system will call the listener when we exceed the percentage of available memory specified. There should only
* be one instance of this object created, since the usage threshold can only be set to one number.
*/
public class OMemoryWatchDog {
private final Collection<Listener> listeners = new CopyOnWriteArrayList<Listener>();
private static final MemoryPoolMXBean tenuredGenPool = findTenuredGenPool();
private int alertTimes = 0;
public interface Listener {
public enum TYPE {
OS, JVM
}
/**
* Execute a soft free of memory resources.
*
* @param iType
* OS or JVM
* @param iUsedMemory
* Current used memory
* @param iMaxMemory
* Max memory
*/
public void memoryUsageLow(TYPE iType, long iUsedMemory, long iMaxMemory);
/**
* Execute a hard free of memory resources.
*
* @param iType
* OS or JVM
* @param iUsedMemory
* Current used memory
* @param iMaxMemory
* Max memory
*/
public void memoryUsageCritical(TYPE iType, long iUsedMemory, long iMaxMemory);
}
/**
* Create the memory watch dog with the default memory threshold.
*
* @param iThreshold
*/
public OMemoryWatchDog(final float iThreshold) {
OMemoryWatchDog.setPercentageUsageThreshold(iThreshold);
final MemoryMXBean memBean = ManagementFactory.getMemoryMXBean();
final NotificationEmitter memEmitter = (NotificationEmitter) memBean;
memEmitter.addNotificationListener(new NotificationListener() {
public synchronized void handleNotification(Notification n, Object hb) {
if (n.getType().equals(MemoryNotificationInfo.MEMORY_THRESHOLD_EXCEEDED)) {
alertTimes++;
long maxMemory = tenuredGenPool.getUsage().getMax();
long usedMemory = tenuredGenPool.getUsage().getUsed();
long freeMemory = maxMemory - usedMemory;
if (OLogManager.instance().isDebugEnabled())
OLogManager.instance().debug(this,
"Free memory is low %s %s%% (used %s of %s), calling listeners to free memory in SOFT way...",
OFileUtils.getSizeAsString(freeMemory), freeMemory * 100 / maxMemory, OFileUtils.getSizeAsString(usedMemory),
OFileUtils.getSizeAsString(maxMemory));
final long timer = OProfiler.getInstance().startChrono();
for (Listener listener : listeners) {
try {
listener.memoryUsageLow(TYPE.JVM, usedMemory, maxMemory);
} catch (Exception e) {
e.printStackTrace();
}
}
long threshold;
do {
// INVOKE GC AND WAIT A BIT
freeMemory(100);
// RECHECK IF MEMORY IS OK NOW
maxMemory = tenuredGenPool.getUsage().getMax();
usedMemory = tenuredGenPool.getUsage().getUsed();
freeMemory = maxMemory - usedMemory;
threshold = (long) (maxMemory * (1 - OGlobalConfiguration.MEMORY_OPTIMIZE_THRESHOLD.getValueAsFloat()));
if (OLogManager.instance().isDebugEnabled())
OLogManager.instance().debug(this, "Free memory now is %s %s%% (used %s of %s) with threshold for HARD clean is %s",
OFileUtils.getSizeAsString(freeMemory), freeMemory * 100 / maxMemory, OFileUtils.getSizeAsString(usedMemory),
OFileUtils.getSizeAsString(maxMemory), OFileUtils.getSizeAsString(threshold));
if (freeMemory < threshold) {
if (OLogManager.instance().isDebugEnabled())
OLogManager
.instance()
.debug(
this,
"Free memory is low %s %s%% (used %s of %s) while the threshold is %s, calling listeners to free memory in HARD way...",
OFileUtils.getSizeAsString(freeMemory), freeMemory * 100 / maxMemory,
OFileUtils.getSizeAsString(usedMemory), OFileUtils.getSizeAsString(maxMemory),
OFileUtils.getSizeAsString(threshold));
for (Listener listener : listeners) {
try {
listener.memoryUsageCritical(TYPE.JVM, usedMemory, maxMemory);
} catch (Exception e) {
e.printStackTrace();
}
}
}
} while (freeMemory < threshold);
OProfiler.getInstance().stopChrono("OMemoryWatchDog.freeResources", timer);
}
}
}, null, null);
OProfiler.getInstance().registerHookValue("memory.alerts", new OProfilerHookValue() {
public Object getValue() {
return alertTimes;
}
});
}
public Collection<Listener> getListeners() {
return listeners;
}
public Listener addListener(Listener listener) {
listeners.add(listener);
return listener;
}
public boolean removeListener(Listener listener) {
return listeners.remove(listener);
}
public static void setPercentageUsageThreshold(double percentage) {
if (percentage <= 0.0 || percentage > 1.0) {
throw new IllegalArgumentException("Percentage not in range");
}
long maxMemory = tenuredGenPool.getUsage().getMax();
long warningThreshold = (long) (maxMemory * percentage);
tenuredGenPool.setUsageThreshold(warningThreshold);
}
/**
* Tenured Space Pool can be determined by it being of type HEAP and by it being possible to set the usage threshold.
*/
private static MemoryPoolMXBean findTenuredGenPool() {
for (MemoryPoolMXBean pool : ManagementFactory.getMemoryPoolMXBeans()) {
// I don't know whether this approach is better, or whether
// we should rather check for the pool name "Tenured Gen"?
if (pool.getType() == MemoryType.HEAP && pool.isUsageThresholdSupported()) {
return pool;
}
}
throw new AssertionError("Could not find tenured space");
}
public static void freeMemory(final long iDelayTime) {
// INVOKE GC AND WAIT A BIT
System.gc();
if (iDelayTime > 0)
try {
Thread.sleep(iDelayTime);
} catch (InterruptedException e) {
}
}
}