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/**
* 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 io.journalkeeper.persistence.local.cache;
import io.journalkeeper.utils.format.Format;
import io.journalkeeper.utils.spi.Singleton;
import io.journalkeeper.utils.threads.AsyncLoopThread;
import io.journalkeeper.utils.threads.ThreadBuilder;
import io.journalkeeper.utils.threads.Threads;
import io.journalkeeper.utils.threads.ThreadsFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import sun.misc.Cleaner;
import sun.misc.VM;
import sun.nio.ch.DirectBuffer;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.stream.Collectors;
import java.util.stream.Stream;
/**
* @author LiYue
* Date: 2018-12-20
*/
@Singleton
public class PreloadBufferPool implements MemoryCacheManager {
private static final Logger logger = LoggerFactory.getLogger(PreloadBufferPool.class);
private static final String PRELOAD_THREAD = "PreloadBuffer-PreloadThread";
private static final String EVICT_THREAD = "PreloadBuffer-EvictThread";
// 缓存比率：如果非堆内存使用率超过这个比率，就不再申请内存，抛出OOM。
// 由于jvm在读写文件的时候会用到少量DirectBuffer作为缓存，必须预留一部分。
private final static double DEFAULT_CACHE_RATIO = 0.9d;
/**
* 缓存清理比率阈值，超过这个阈值执行缓存清理。
*/
private static final float DEFAULT_EVICT_RATIO = 0.9f;
/**
* 缓存核心利用率，系统会尽量将这个比率以内的内存用满。
*/
private static final float DEFAULT_CORE_RATIO = 0.8f;
private static final long DEFAULT_WRITE_PAGE_EXTRA_WEIGHT_MS = 60000L;
private final static long INTERVAL_MS = 50L;
private final static String MAX_MEMORY_KEY = "memory_cache.max_memory";
private final static String EVICT_RATIO_KEY = "memory_cache.evict_ratio";
private final static String CORE_RATIO_KEY = "memory_cache.core_ratio";
private static final String WRITE_PAGE_EXTRA_WEIGHT_MS_KEY="memory_cache.write.weight.ms";
private static final PreloadBufferPool instance = null;
private final Threads threads = ThreadsFactory.create();
// 可用的堆外内存上限，这个上限可以用JVM参数"PreloadBufferPool.MaxMemory"指定，
// 默认为虚拟机最大内存（VM.maxDirectMemory()）的90%。
private final long maxMemorySize;
// 核心堆外内存大小，JournalKeeper总是尽量占满coreMemorySize内存用于缓存更多的文件，提升读写性能。
private final long coreMemorySize;
// 堆外内存超过evictMemorySize就会启动清理，清理的策略是LRU
private final long evictMemorySize;
// 正在写入的页在置换时有额外的权重，这个权重用时间Ms体现。
// 默认是60秒。
// 置换权重 = 上次访问时间戳 + 额外权重，优先从内存中驱逐权重小的页。
// 例如：一个只读的页，上次访问时间戳是T，一个读写页，上次访问时间是T - 60秒，
// 这两个页在置换时有同样的权重
private final long writePageExtraWeightMs;
private final AtomicLong usedSize = new AtomicLong(0L);
private final Set directBufferHolders = ConcurrentHashMap.newKeySet();
private final Set mMapBufferHolders = ConcurrentHashMap.newKeySet();
private Map bufferCache = new ConcurrentHashMap<>();
public PreloadBufferPool() {
maxMemorySize = calcMaxMemorySize();
float evictRatio = getFloatProperty(EVICT_RATIO_KEY, DEFAULT_EVICT_RATIO);
evictMemorySize = Math.round(maxMemorySize * evictRatio);
float coreRatio = getFloatProperty(CORE_RATIO_KEY, DEFAULT_CORE_RATIO);
coreMemorySize = Math.round(maxMemorySize * coreRatio);
writePageExtraWeightMs = Long.parseLong(System.getProperty(WRITE_PAGE_EXTRA_WEIGHT_MS_KEY,String.valueOf(DEFAULT_WRITE_PAGE_EXTRA_WEIGHT_MS)));
threads.createThread(buildPreloadThread());
threads.createThread(buildEvictThread());
threads.start();
logger.info("JournalKeeper PreloadBufferPool loaded, max direct memory: {}, core direct memory: {}, evict direct memory: {}.",
Format.formatSize(maxMemorySize),
Format.formatSize(coreMemorySize),
Format.formatSize(evictMemorySize));
}
private static float getFloatProperty(String key, float defaultValue) {
try {
return Float.parseFloat(System.getProperty(key, String.valueOf(defaultValue)));
} catch (NumberFormatException e) {
return defaultValue;
}
}
private AsyncLoopThread buildPreloadThread() {
return ThreadBuilder.builder()
.name(PRELOAD_THREAD)
.sleepTime(INTERVAL_MS, INTERVAL_MS)
.doWork(this::preLoadBuffer)
.onException(e -> logger.warn("{} exception:", PRELOAD_THREAD, e))
.daemon(true)
.build();
}
private AsyncLoopThread buildEvictThread() {
return ThreadBuilder.builder()
.name(EVICT_THREAD)
.sleepTime(INTERVAL_MS, INTERVAL_MS)
.condition(() -> usedSize.get() > evictMemorySize)
.doWork(this::evict)
.onException(e -> logger.warn("{} exception:", EVICT_THREAD, e))
.daemon(true)
.build();
}
/**
* 清除文件缓存页。LRU。
*/
private synchronized void evict() {
// 清理超过maxCount的缓存页
for (PreLoadCache preLoadCache : bufferCache.values()) {
if (!needEviction()) {
break;
}
while (preLoadCache.cache.size() > preLoadCache.maxCount && !needEviction()) {
try {
destroyOne(preLoadCache.cache.remove());
} catch (NoSuchElementException ignored) {
}
}
}
// 清理使用中最旧的页面，直到内存占用率达标
if (needEviction()) {
List> sorted;
sorted = Stream.concat(directBufferHolders.stream(), mMapBufferHolders.stream())
.filter(BufferHolder::isFree)
.map(bufferHolder -> new LruWrapper<>(bufferHolder, bufferHolder.lastAccessTime(), bufferHolder.writable() ? writePageExtraWeightMs : 0L))
.sorted(Comparator.comparing(LruWrapper::getWeight))
.collect(Collectors.toList());
while (needEviction() && !sorted.isEmpty()) {
LruWrapper wrapper = sorted.remove(0);
BufferHolder holder = wrapper.get();
if (holder.lastAccessTime() == wrapper.getLastAccessTime()) {
holder.evict();
}
}
}
}
@Override
public void printMetric() {
long totalUsed = usedSize.get();
long plUsed = bufferCache.values().stream().mapToLong(preLoadCache -> {
long cached = preLoadCache.cache.size();
long usedPreLoad = preLoadCache.onFlyCounter.get();
long totalSize = preLoadCache.bufferSize * (cached + usedPreLoad);
logger.info("PreloadCache usage: cached: {} * {} = {}, used: {} * {} = {}, total: {}",
Format.formatSize(preLoadCache.bufferSize), cached, Format.formatSize(preLoadCache.bufferSize * cached),
Format.formatSize(preLoadCache.bufferSize), usedPreLoad, Format.formatSize(preLoadCache.bufferSize * usedPreLoad),
Format.formatSize(totalSize));
return totalSize;
}).sum();
long mmpUsed = mMapBufferHolders.stream().mapToLong(BufferHolder::size).sum();
long directUsed = directBufferHolders.stream().mapToLong(BufferHolder::size).sum();
logger.info("Direct memory usage: preload/direct/mmp/used/max: {}/{}/{}/{}/{}.",
Format.formatSize(plUsed),
Format.formatSize(directUsed),
Format.formatSize(mmpUsed),
Format.formatSize(totalUsed),
Format.formatSize(maxMemorySize));
}
private boolean needEviction() {
return usedSize.get() > evictMemorySize;
}
private boolean isOutOfMemory() {
return usedSize.get() > maxMemorySize;
}
private boolean isHungry() {
return usedSize.get() < coreMemorySize;
}
@Override
public synchronized void addPreLoad(int bufferSize, int coreCount, int maxCount) {
PreLoadCache preLoadCache = bufferCache.putIfAbsent(bufferSize, new PreLoadCache(bufferSize, coreCount, maxCount));
if (null != preLoadCache) {
preLoadCache.referenceCount.incrementAndGet();
}
}
@Override
public synchronized void removePreLoad(int bufferSize) {
PreLoadCache preLoadCache = bufferCache.get(bufferSize);
if (null != preLoadCache) {
if (preLoadCache.referenceCount.decrementAndGet() <= 0) {
bufferCache.remove(bufferSize);
preLoadCache.cache.forEach(this::destroyOne);
}
}
}
private void destroyOne(ByteBuffer byteBuffer) {
usedSize.getAndAdd(-1 * byteBuffer.capacity());
releaseIfDirect(byteBuffer);
}
private void preLoadBuffer() {
for (PreLoadCache preLoadCache : bufferCache.values()) {
if (preLoadCache.cache.size() < preLoadCache.coreCount) {
if (isHungry()) {
try {
while (preLoadCache.cache.size() < preLoadCache.coreCount && usedSize.get() + preLoadCache.bufferSize < maxMemorySize) {
preLoadCache.cache.add(createOne(preLoadCache.bufferSize));
}
} catch (OutOfMemoryError ignored) {
return;
}
} else {
List> outdated = directBufferHolders.stream()
.filter(b -> b.size() == preLoadCache.bufferSize)
.filter(BufferHolder::isFree)
.map(bufferHolder -> new LruWrapper<>(bufferHolder, bufferHolder.lastAccessTime(), bufferHolder.writable() ? writePageExtraWeightMs : 0L))
.sorted(Comparator.comparing(LruWrapper::getWeight))
.collect(Collectors.toList());
while (preLoadCache.cache.size() < preLoadCache.coreCount && !outdated.isEmpty()) {
LruWrapper wrapper = outdated.remove(0);
BufferHolder holder = wrapper.get();
if (holder.lastAccessTime() == wrapper.getLastAccessTime()) {
holder.evict();
}
}
}
}
}
}
private ByteBuffer createOne(int size) {
reserveMemory(size);
return ByteBuffer.allocateDirect(size);
}
private void reserveMemory(int size) {
usedSize.addAndGet(size);
try {
while (isOutOfMemory()) {
PreLoadCache preLoadCache = bufferCache.values().stream()
.filter(p -> p.cache.size() > 0)
.findAny().orElse(null);
if (null != preLoadCache) {
destroyOne(preLoadCache.cache.remove());
} else {
break;
}
}
if (isOutOfMemory()) {
// 如果内存不足，唤醒清理线程立即执行清理
threads.wakeupThread(EVICT_THREAD);
// 等待5x10ms，如果还不足抛出异常
for (int i = 0; i < 5 && isOutOfMemory(); i++) {
try {
Thread.sleep(10);
} catch (InterruptedException e) {
logger.warn("Interrupted: ", e);
}
}
if (isOutOfMemory()) {
throw new OutOfMemoryError();
}
}
} catch (Throwable t) {
usedSize.getAndAdd(-1 * size);
}
}
private void releaseIfDirect(ByteBuffer byteBuffer) {
if (byteBuffer instanceof DirectBuffer) {
try {
Method getCleanerMethod;
getCleanerMethod = byteBuffer.getClass().getMethod("cleaner");
getCleanerMethod.setAccessible(true);
Cleaner cleaner = (Cleaner) getCleanerMethod.invoke(byteBuffer, new Object[0]);
cleaner.clean();
} catch (Exception e) {
logger.warn("Exception: ", e);
}
}
}
@Override
public void allocateMMap(BufferHolder bufferHolder) {
reserveMemory(bufferHolder.size());
mMapBufferHolders.add(bufferHolder);
}
@Override
public ByteBuffer allocateDirect(int bufferSize, BufferHolder bufferHolder) {
ByteBuffer buffer = allocateDirect(bufferSize);
directBufferHolders.add(bufferHolder);
return buffer;
}
private ByteBuffer allocateDirect(int bufferSize) {
try {
PreLoadCache preLoadCache = bufferCache.get(bufferSize);
if (null != preLoadCache) {
try {
ByteBuffer byteBuffer = preLoadCache.cache.remove();
preLoadCache.onFlyCounter.getAndIncrement();
return byteBuffer;
} catch (NoSuchElementException e) {
logger.warn("Pool is empty, create ByteBuffer: {}", Format.formatSize(bufferSize));
ByteBuffer byteBuffer = createOne(bufferSize);
preLoadCache.onFlyCounter.getAndIncrement();
threads.wakeupThread(PRELOAD_THREAD);
return byteBuffer;
}
} else {
logger.warn("No cached buffer in pool, create ByteBuffer: {}", Format.formatSize(bufferSize));
return createOne(bufferSize);
}
} catch (OutOfMemoryError outOfMemoryError) {
logger.debug("OOM: {}/{}.", Format.formatSize(usedSize.get()), Format.formatSize(maxMemorySize));
throw outOfMemoryError;
}
}
@Override
public void releaseDirect(ByteBuffer byteBuffer, BufferHolder bufferHolder) {
directBufferHolders.remove(bufferHolder);
int size = byteBuffer.capacity();
PreLoadCache preLoadCache = bufferCache.get(size);
if (null != preLoadCache) {
if (needEviction() && preLoadCache.cache.size() >= preLoadCache.maxCount) {
destroyOne(byteBuffer);
} else {
byteBuffer.clear();
preLoadCache.cache.add(byteBuffer);
}
preLoadCache.onFlyCounter.getAndDecrement();
} else {
destroyOne(byteBuffer);
}
}
@Override
public void releaseMMap(BufferHolder bufferHolder) {
mMapBufferHolders.remove(bufferHolder);
usedSize.getAndAdd(-1 * bufferHolder.size());
}
@Override
public Collection getCaches() {
return new ArrayList<>(bufferCache.values());
}
@Override
public long getMaxMemorySize() {
return maxMemorySize;
}
@Override
public long getTotalUsedMemorySize() {
return usedSize.get();
}
@Override
public long getDirectUsedMemorySize() {
return directBufferHolders.stream().mapToLong(BufferHolder::size).sum() +
bufferCache.values().stream().mapToLong(c -> c.getBufferSize() * c.getCachedCount()).sum();
}
/**
* 计算可供缓存使用的最大堆外内存。
*
* 1. 如果PreloadBufferPool.MaxMemory设置为数值，直接使用设置值。
* 2. 如果PreloadBufferPool.MaxMemory设置为百分比，比如：90%，最大堆外内存 = 物理内存 * 90% - 最大堆内存（由JVM参数-Xmx配置）
* 3. 如果PreloadBufferPool.MaxMemory未设置或者设置了非法值，最大堆外内存 = VM.maxDirectMemory() * 90%。
* 其中VM.maxDirectMemory()取值为JVM参数-XX:MaxDirectMemorySize，如果未设置-XX:MaxDirectMemorySize，取值为JVM参数-Xmx。
*
* @return 可使用的最大堆外内存大小。
*/
private long calcMaxMemorySize() {
String mmsString = System.getProperty(MAX_MEMORY_KEY);
int pct = Format.getPercentage(mmsString);
if (pct > 0 && pct < 100) {
long physicalMemorySize = getPhysicalMemorySize();
long reservedHeapMemorySize = Runtime.getRuntime().maxMemory();
if (Long.MAX_VALUE == reservedHeapMemorySize) {
logger.warn("Runtime.getRuntime().maxMemory() returns unlimited!");
reservedHeapMemorySize = physicalMemorySize / 2;
}
// 如果设置了百分比，最大可使用堆外内存= 物理内存 * 百分比 - 最大堆内存
long mms = physicalMemorySize * pct / 100 - reservedHeapMemorySize;
if (mms > 0) {
return mms;
} else {
return Math.round(VM.maxDirectMemory() * DEFAULT_CACHE_RATIO);
}
}
return Format.parseSize(System.getProperty(MAX_MEMORY_KEY), Math.round(VM.maxDirectMemory() * DEFAULT_CACHE_RATIO));
}
private static long getPhysicalMemorySize() {
com.sun.management.OperatingSystemMXBean os = (com.sun.management.OperatingSystemMXBean)
java.lang.management.ManagementFactory.getOperatingSystemMXBean();
return os.getTotalPhysicalMemorySize();
}
@Override
public void close() {
if (null != PreloadBufferPool.instance) {
PreloadBufferPool.instance.threads.stop();
PreloadBufferPool.instance.bufferCache.values().forEach(p -> {
while (!p.cache.isEmpty()) {
PreloadBufferPool.instance.destroyOne(p.cache.remove());
}
});
PreloadBufferPool.instance.directBufferHolders.parallelStream().forEach(BufferHolder::evict);
PreloadBufferPool.instance.mMapBufferHolders.parallelStream().forEach(BufferHolder::evict);
PreloadBufferPool.instance.bufferCache.values().forEach(p -> {
while (!p.cache.isEmpty()) {
PreloadBufferPool.instance.destroyOne(p.cache.remove());
}
});
}
PreloadBufferPool.logger.info("Preload buffer pool closed.");
}
@Override
public long getMapUsedMemorySize() {
return mMapBufferHolders.stream().mapToLong(BufferHolder::size).sum();
}
public static class PreLoadCache implements PreloadCacheMetric {
private final int bufferSize;
private final int coreCount, maxCount;
private final Queue cache = new ConcurrentLinkedQueue<>();
private final AtomicInteger onFlyCounter = new AtomicInteger(0);
private final AtomicInteger referenceCount;
PreLoadCache(int bufferSize, int coreCount, int maxCount) {
this.bufferSize = bufferSize;
this.coreCount = coreCount;
this.maxCount = maxCount;
this.referenceCount = new AtomicInteger(1);
}
public int getBufferSize() {
return bufferSize;
}
public int getCoreCount() {
return coreCount;
}
public int getMaxCount() {
return maxCount;
}
public int getUsedCount() {
return onFlyCounter.get();
}
public int getCachedCount() {
return cache.size();
}
}
private static class LruWrapper {
private final long lastAccessTime;
private final long extraWeight;
private final V t;
LruWrapper(V t, long lastAccessTime, long extraWeight) {
this.lastAccessTime = lastAccessTime;
this.t = t;
this.extraWeight = extraWeight;
}
private long getLastAccessTime() {
return lastAccessTime;
}
private V get() {
return t;
}
private long getWeight() {
return lastAccessTime + extraWeight;
}
}
}