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8137333: Boundless soft caching of property map histories causes high memory pressure

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Reviewed-by: hannesw, sundar
This commit is contained in:
Attila Szegedi 2015-09-30 10:09:44 +02:00
parent be533e6f12
commit f3ff9a5c9a
1 changed files with 41 additions and 21 deletions

62
nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/PropertyMap.java

@ -34,7 +34,9 @@ import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.lang.invoke.SwitchPoint;
import java.lang.ref.Reference;
import java.lang.ref.SoftReference;
import java.lang.ref.WeakReference;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Collection;
@ -43,6 +45,7 @@ import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.WeakHashMap;
import java.util.concurrent.atomic.LongAdder;
import jdk.nashorn.internal.runtime.options.Options;
import jdk.nashorn.internal.scripts.JO;
/**
@ -55,6 +58,9 @@ import jdk.nashorn.internal.scripts.JO;
* will return a new map.
*/
public class PropertyMap implements Iterable<Object>, Serializable {
private static final int INITIAL_SOFT_REFERENCE_DERIVATION_LIMIT =
Math.max(0, Options.getIntProperty("nashorn.propertyMap.softReferenceDerivationLimit", 32));
/** Used for non extensible PropertyMaps, negative logic as the normal case is extensible. See {@link ScriptObject#preventExtensions()} */
private static final int NOT_EXTENSIBLE = 0b0000_0001;
/** Does this map contain valid array keys? */
@ -78,6 +84,13 @@ public class PropertyMap implements Iterable<Object>, Serializable {
/** Structure class name */
private final String className;
/**
* Countdown of number of times this property map has been derived from another property map. When it
* reaches zero, the property map will start using weak references instead of soft references to hold on
* to its history elements.
*/
private final int softReferenceDerivationLimit;
/** A reference to the expected shared prototype property map. If this is set this
* property map should only be used if it the same as the actual prototype map. */
private transient SharedPropertyMap sharedProtoMap;
@ -86,7 +99,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
private transient HashMap<String, SwitchPoint> protoSwitches;
/** History of maps, used to limit map duplication. */
private transient WeakHashMap<Property, SoftReference<PropertyMap>> history;
private transient WeakHashMap<Property, Reference<PropertyMap>> history;
/** History of prototypes, used to limit map duplication. */
private transient WeakHashMap<ScriptObject, SoftReference<PropertyMap>> protoHistory;
@ -114,6 +127,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
this.fieldMaximum = fieldMaximum;
this.spillLength = spillLength;
this.flags = flags;
this.softReferenceDerivationLimit = INITIAL_SOFT_REFERENCE_DERIVATION_LIMIT;
if (Context.DEBUG) {
count.increment();
@ -126,7 +140,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
* @param propertyMap Existing property map.
* @param properties A {@link PropertyHashMap} with a new set of properties.
*/
private PropertyMap(final PropertyMap propertyMap, final PropertyHashMap properties, final int flags, final int fieldCount, final int spillLength) {
private PropertyMap(final PropertyMap propertyMap, final PropertyHashMap properties, final int flags, final int fieldCount, final int spillLength, final int softReferenceDerivationLimit) {
this.properties = properties;
this.flags = flags;
this.spillLength = spillLength;
@ -137,6 +151,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
this.listeners = propertyMap.listeners;
this.freeSlots = propertyMap.freeSlots;
this.sharedProtoMap = propertyMap.sharedProtoMap;
this.softReferenceDerivationLimit = softReferenceDerivationLimit;
if (Context.DEBUG) {
count.increment();
@ -150,7 +165,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
* @param propertyMap Existing property map.
*/
protected PropertyMap(final PropertyMap propertyMap) {
this(propertyMap, propertyMap.properties, propertyMap.flags, propertyMap.fieldCount, propertyMap.spillLength);
this(propertyMap, propertyMap.properties, propertyMap.flags, propertyMap.fieldCount, propertyMap.spillLength, propertyMap.softReferenceDerivationLimit);
}
private void writeObject(final ObjectOutputStream out) throws IOException {
@ -438,11 +453,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
*/
public final PropertyMap addPropertyNoHistory(final Property property) {
propertyAdded(property, true);
final PropertyHashMap newProperties = properties.immutableAdd(property);
final PropertyMap newMap = new PropertyMap(this, newProperties, newFlags(property), newFieldCount(property), newSpillLength(property));
newMap.updateFreeSlots(null, property);
return newMap;
return addPropertyInternal(property);
}
/**
@ -457,15 +468,24 @@ public class PropertyMap implements Iterable<Object>, Serializable {
PropertyMap newMap = checkHistory(property);
if (newMap == null) {
final PropertyHashMap newProperties = properties.immutableAdd(property);
newMap = new PropertyMap(this, newProperties, newFlags(property), newFieldCount(property), newSpillLength(property));
newMap.updateFreeSlots(null, property);
newMap = addPropertyInternal(property);
addToHistory(property, newMap);
}
return newMap;
}
private PropertyMap deriveMap(final PropertyHashMap newProperties, final int newFlags, final int newFieldCount, final int newSpillLength) {
return new PropertyMap(this, newProperties, newFlags, newFieldCount, newSpillLength, softReferenceDerivationLimit == 0 ? 0 : softReferenceDerivationLimit - 1);
}
private PropertyMap addPropertyInternal(final Property property) {
final PropertyHashMap newProperties = properties.immutableAdd(property);
final PropertyMap newMap = deriveMap(newProperties, newFlags(property), newFieldCount(property), newSpillLength(property));
newMap.updateFreeSlots(null, property);
return newMap;
}
/**
* Remove a property from a map. Cloning or using an existing map if available.
*
@ -485,13 +505,13 @@ public class PropertyMap implements Iterable<Object>, Serializable {
// If deleted property was last field or spill slot we can make it reusable by reducing field/slot count.
// Otherwise mark it as free in free slots bitset.
if (isSpill && slot >= 0 && slot == spillLength - 1) {
newMap = new PropertyMap(this, newProperties, flags, fieldCount, spillLength - 1);
newMap = deriveMap(newProperties, flags, fieldCount, spillLength - 1);
newMap.freeSlots = freeSlots;
} else if (!isSpill && slot >= 0 && slot == fieldCount - 1) {
newMap = new PropertyMap(this, newProperties, flags, fieldCount - 1, spillLength);
newMap = deriveMap(newProperties, flags, fieldCount - 1, spillLength);
newMap.freeSlots = freeSlots;
} else {
newMap = new PropertyMap(this, newProperties, flags, fieldCount, spillLength);
newMap = deriveMap(newProperties, flags, fieldCount, spillLength);
newMap.updateFreeSlots(property, null);
}
addToHistory(property, newMap);
@ -539,7 +559,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
// Add replaces existing property.
final PropertyHashMap newProperties = properties.immutableReplace(oldProperty, newProperty);
final PropertyMap newMap = new PropertyMap(this, newProperties, flags, fieldCount, newSpillLength);
final PropertyMap newMap = deriveMap(newProperties, flags, fieldCount, newSpillLength);
if (!sameType) {
newMap.updateFreeSlots(oldProperty, newProperty);
@ -584,7 +604,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
final Property[] otherProperties = other.properties.getProperties();
final PropertyHashMap newProperties = properties.immutableAdd(otherProperties);
final PropertyMap newMap = new PropertyMap(this, newProperties, flags, fieldCount, spillLength);
final PropertyMap newMap = deriveMap(newProperties, flags, fieldCount, spillLength);
for (final Property property : otherProperties) {
// This method is only safe to use with non-slotted, native getter/setter properties
assert property.getSlot() == -1;
@ -618,7 +638,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
* @return New map with {@link #NOT_EXTENSIBLE} flag set.
*/
PropertyMap preventExtensions() {
return new PropertyMap(this, properties, flags | NOT_EXTENSIBLE, fieldCount, spillLength);
return deriveMap(properties, flags | NOT_EXTENSIBLE, fieldCount, spillLength);
}
/**
@ -634,7 +654,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
newProperties = newProperties.immutableAdd(oldProperty.addFlags(Property.NOT_CONFIGURABLE));
}
return new PropertyMap(this, newProperties, flags | NOT_EXTENSIBLE, fieldCount, spillLength);
return deriveMap(newProperties, flags | NOT_EXTENSIBLE, fieldCount, spillLength);
}
/**
@ -656,7 +676,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
newProperties = newProperties.immutableAdd(oldProperty.addFlags(propertyFlags));
}
return new PropertyMap(this, newProperties, flags | NOT_EXTENSIBLE, fieldCount, spillLength);
return deriveMap(newProperties, flags | NOT_EXTENSIBLE, fieldCount, spillLength);
}
/**
@ -743,7 +763,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
history = new WeakHashMap<>();
}
history.put(property, new SoftReference<>(newMap));
history.put(property, softReferenceDerivationLimit == 0 ? new WeakReference<>(newMap) : new SoftReference<>(newMap));
}
/**
@ -756,7 +776,7 @@ public class PropertyMap implements Iterable<Object>, Serializable {
private PropertyMap checkHistory(final Property property) {
if (history != null) {
final SoftReference<PropertyMap> ref = history.get(property);
final Reference<PropertyMap> ref = history.get(property);
final PropertyMap historicMap = ref == null ? null : ref.get();
if (historicMap != null) {