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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you 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.elasticsearch.common.util;
import org.apache.lucene.util.RamUsageEstimator;
import org.elasticsearch.common.recycler.AbstractRecyclerC;
import org.elasticsearch.common.recycler.Recycler;
import org.elasticsearch.common.settings.Setting;
import org.elasticsearch.common.settings.Setting.Property;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.unit.ByteSizeValue;
import org.elasticsearch.common.util.concurrent.EsExecutors;
import java.util.Arrays;
import java.util.Locale;
import static org.elasticsearch.common.recycler.Recyclers.concurrent;
import static org.elasticsearch.common.recycler.Recyclers.concurrentDeque;
import static org.elasticsearch.common.recycler.Recyclers.dequeFactory;
import static org.elasticsearch.common.recycler.Recyclers.none;
/** A recycler of fixed-size pages. */
public class PageCacheRecycler {
public static final Setting TYPE_SETTING =
new Setting<>("cache.recycler.page.type", Type.CONCURRENT.name(), Type::parse, Property.NodeScope);
public static final Setting LIMIT_HEAP_SETTING =
Setting.memorySizeSetting("cache.recycler.page.limit.heap", "10%", Property.NodeScope);
public static final Setting WEIGHT_BYTES_SETTING =
Setting.doubleSetting("cache.recycler.page.weight.bytes", 1d, 0d, Property.NodeScope);
public static final Setting WEIGHT_LONG_SETTING =
Setting.doubleSetting("cache.recycler.page.weight.longs", 1d, 0d, Property.NodeScope);
public static final Setting WEIGHT_INT_SETTING =
Setting.doubleSetting("cache.recycler.page.weight.ints", 1d, 0d, Property.NodeScope);
// object pages are less useful to us so we give them a lower weight by default
public static final Setting WEIGHT_OBJECTS_SETTING =
Setting.doubleSetting("cache.recycler.page.weight.objects", 0.1d, 0d, Property.NodeScope);
/** Page size in bytes: 16KB */
public static final int PAGE_SIZE_IN_BYTES = 1 << 14;
public static final int OBJECT_PAGE_SIZE = PAGE_SIZE_IN_BYTES / RamUsageEstimator.NUM_BYTES_OBJECT_REF;
public static final int LONG_PAGE_SIZE = PAGE_SIZE_IN_BYTES / Long.BYTES;
public static final int INT_PAGE_SIZE = PAGE_SIZE_IN_BYTES / Integer.BYTES;
public static final int BYTE_PAGE_SIZE = PAGE_SIZE_IN_BYTES;
private final Recycler bytePage;
private final Recycler intPage;
private final Recycler longPage;
private final Recycler objectPage;
public static final PageCacheRecycler NON_RECYCLING_INSTANCE;
static {
NON_RECYCLING_INSTANCE = new PageCacheRecycler(Settings.builder().put(LIMIT_HEAP_SETTING.getKey(), "0%").build());
}
public PageCacheRecycler(Settings settings) {
final Type type = TYPE_SETTING.get(settings);
final long limit = LIMIT_HEAP_SETTING.get(settings).getBytes();
final int availableProcessors = EsExecutors.numberOfProcessors(settings);
// We have a global amount of memory that we need to divide across data types.
// Since some types are more useful than other ones we give them different weights.
// Trying to store all of them in a single stack would be problematic because eg.
// a work load could fill the recycler with only byte[] pages and then another
// workload that would work with double[] pages couldn't recycle them because there
// is no space left in the stack/queue. LRU/LFU policies are not an option either
// because they would make obtain/release too costly: we really need constant-time
// operations.
// Ultimately a better solution would be to only store one kind of data and have the
// ability to interpret it either as a source of bytes, doubles, longs, etc. eg. thanks
// to direct ByteBuffers or sun.misc.Unsafe on a byte[] but this would have other issues
// that would need to be addressed such as garbage collection of native memory or safety
// of Unsafe writes.
final double bytesWeight = WEIGHT_BYTES_SETTING .get(settings);
final double intsWeight = WEIGHT_INT_SETTING .get(settings);
final double longsWeight = WEIGHT_LONG_SETTING .get(settings);
final double objectsWeight = WEIGHT_OBJECTS_SETTING .get(settings);
final double totalWeight = bytesWeight + intsWeight + longsWeight + objectsWeight;
final int maxPageCount = (int) Math.min(Integer.MAX_VALUE, limit / PAGE_SIZE_IN_BYTES);
final int maxBytePageCount = (int) (bytesWeight * maxPageCount / totalWeight);
bytePage = build(type, maxBytePageCount, availableProcessors, new AbstractRecyclerC() {
@Override
public byte[] newInstance() {
return new byte[BYTE_PAGE_SIZE];
}
@Override
public void recycle(byte[] value) {
// nothing to do
}
});
final int maxIntPageCount = (int) (intsWeight * maxPageCount / totalWeight);
intPage = build(type, maxIntPageCount, availableProcessors, new AbstractRecyclerC() {
@Override
public int[] newInstance() {
return new int[INT_PAGE_SIZE];
}
@Override
public void recycle(int[] value) {
// nothing to do
}
});
final int maxLongPageCount = (int) (longsWeight * maxPageCount / totalWeight);
longPage = build(type, maxLongPageCount, availableProcessors, new AbstractRecyclerC() {
@Override
public long[] newInstance() {
return new long[LONG_PAGE_SIZE];
}
@Override
public void recycle(long[] value) {
// nothing to do
}
});
final int maxObjectPageCount = (int) (objectsWeight * maxPageCount / totalWeight);
objectPage = build(type, maxObjectPageCount, availableProcessors, new AbstractRecyclerC() {
@Override
public Object[] newInstance() {
return new Object[OBJECT_PAGE_SIZE];
}
@Override
public void recycle(Object[] value) {
Arrays.fill(value, null); // we need to remove the strong refs on the objects stored in the array
}
});
assert PAGE_SIZE_IN_BYTES * (maxBytePageCount + maxIntPageCount + maxLongPageCount + maxObjectPageCount) <= limit;
}
public Recycler.V bytePage(boolean clear) {
final Recycler.V v = bytePage.obtain();
if (v.isRecycled() && clear) {
Arrays.fill(v.v(), (byte) 0);
}
return v;
}
public Recycler.V intPage(boolean clear) {
final Recycler.V v = intPage.obtain();
if (v.isRecycled() && clear) {
Arrays.fill(v.v(), 0);
}
return v;
}
public Recycler.V longPage(boolean clear) {
final Recycler.V v = longPage.obtain();
if (v.isRecycled() && clear) {
Arrays.fill(v.v(), 0L);
}
return v;
}
public Recycler.V objectPage() {
// object pages are cleared on release anyway
return objectPage.obtain();
}
private static Recycler build(Type type, int limit, int availableProcessors, Recycler.C c) {
final Recycler recycler;
if (limit == 0) {
recycler = none(c);
} else {
recycler = type.build(c, limit, availableProcessors);
}
return recycler;
}
public enum Type {
QUEUE {
@Override
Recycler build(Recycler.C c, int limit, int availableProcessors) {
return concurrentDeque(c, limit);
}
},
CONCURRENT {
@Override
Recycler build(Recycler.C c, int limit, int availableProcessors) {
return concurrent(dequeFactory(c, limit / availableProcessors), availableProcessors);
}
},
NONE {
@Override
Recycler build(Recycler.C c, int limit, int availableProcessors) {
return none(c);
}
};
public static Type parse(String type) {
try {
return Type.valueOf(type.toUpperCase(Locale.ROOT));
} catch (IllegalArgumentException e) {
throw new IllegalArgumentException("no type support [" + type + "]");
}
}
abstract Recycler build(Recycler.C c, int limit, int availableProcessors);
}
}