hadoop-hdfs-project/hadoop-hdfs-nfs/src/main/java/org/apache/hadoop/hdfs/nfs/nfs3/OpenFileCtxCache.java - hadoop - Git at Google

 /**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF 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.apache.hadoop.hdfs.nfs.nfs3;

 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.Map.Entry;
 import java.util.concurrent.ConcurrentMap;

 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.apache.hadoop.hdfs.nfs.conf.NfsConfigKeys;
 import org.apache.hadoop.hdfs.nfs.conf.NfsConfiguration;
 import org.apache.hadoop.nfs.nfs3.FileHandle;
 import org.apache.hadoop.util.Daemon;
 import org.apache.hadoop.util.Time;

 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Maps;

 /**
  * A cache saves OpenFileCtx objects for different users. Each cache entry is
  * used to maintain the writing context for a single file.
  */
 class OpenFileCtxCache {
   private static final Logger LOG =
       LoggerFactory.getLogger(OpenFileCtxCache.class);
   // Insert and delete with openFileMap are synced
   private final ConcurrentMap<FileHandle, OpenFileCtx> openFileMap = Maps
       .newConcurrentMap();

   private final int maxStreams;
   private final long streamTimeout;
   private final StreamMonitor streamMonitor;

   OpenFileCtxCache(NfsConfiguration config, long streamTimeout) {
     maxStreams = config.getInt(NfsConfigKeys.DFS_NFS_MAX_OPEN_FILES_KEY,
         NfsConfigKeys.DFS_NFS_MAX_OPEN_FILES_DEFAULT);
     LOG.info("Maximum open streams is " + maxStreams);
     this.streamTimeout = streamTimeout;
     streamMonitor = new StreamMonitor();
   }

   /**
    * The entry to be evicted is based on the following rules:<br>
    * 1. if the OpenFileCtx has any pending task, it will not be chosen.<br>
    * 2. if there is inactive OpenFileCtx, the first found one is to evict. <br>
    * 3. For OpenFileCtx entries don't belong to group 1 or 2, the idlest one
    * is select. If it's idle longer than OUTPUT_STREAM_TIMEOUT_MIN_DEFAULT, it
    * will be evicted. Otherwise, the whole eviction request is failed.
    */
   @VisibleForTesting
   Entry<FileHandle, OpenFileCtx> getEntryToEvict() {
     Iterator<Entry<FileHandle, OpenFileCtx>> it = openFileMap.entrySet()
         .iterator();
     if (LOG.isTraceEnabled()) {
       LOG.trace("openFileMap size:" + size());
     }

     Entry<FileHandle, OpenFileCtx> idlest = null;

     while (it.hasNext()) {
       Entry<FileHandle, OpenFileCtx> pairs = it.next();
       OpenFileCtx ctx = pairs.getValue();
       if (!ctx.getActiveState()) {
         if (LOG.isDebugEnabled()) {
           LOG.debug("Got one inactive stream: " + ctx);
         }
         return pairs;
       }
       if (ctx.hasPendingWork()) {
         // Always skip files with pending work.
         continue;
       }
       if (idlest == null) {
         idlest = pairs;
       } else {
         if (ctx.getLastAccessTime() < idlest.getValue().getLastAccessTime()) {
           idlest = pairs;
         }
       }
     }

     if (idlest == null) {
       LOG.warn("No eviction candidate. All streams have pending work.");
       return null;
     } else {
       long idleTime = Time.monotonicNow()
           - idlest.getValue().getLastAccessTime();
       if (idleTime < NfsConfigKeys.DFS_NFS_STREAM_TIMEOUT_MIN_DEFAULT) {
         if (LOG.isDebugEnabled()) {
           LOG.debug("idlest stream's idle time:" + idleTime);
         }
         LOG.warn("All opened streams are busy, can't remove any from cache.");
         return null;
       } else {
         return idlest;
       }
     }
   }

   boolean put(FileHandle h, OpenFileCtx context) {
     OpenFileCtx toEvict = null;
     synchronized (this) {
       Preconditions.checkState(size() <= this.maxStreams,
           "stream cache size " + size() + "  is larger than maximum" + this
               .maxStreams);
       if (size() == this.maxStreams) {
         Entry<FileHandle, OpenFileCtx> pairs = getEntryToEvict();
         if (pairs ==null) {
           return false;
         } else {
           if (LOG.isDebugEnabled()) {
             LOG.debug("Evict stream ctx: " + pairs.getValue());
           }
           toEvict = openFileMap.remove(pairs.getKey());
           Preconditions.checkState(toEvict == pairs.getValue(),
               "The deleted entry is not the same as odlest found.");
         }
       }
       openFileMap.put(h, context);
     }

     // Cleanup the old stream outside the lock
     if (toEvict != null) {
       toEvict.cleanup();
     }
     return true;
   }

   @VisibleForTesting
   void scan(long streamTimeout) {
     ArrayList<OpenFileCtx> ctxToRemove = new ArrayList<OpenFileCtx>();
     Iterator<Entry<FileHandle, OpenFileCtx>> it = openFileMap.entrySet()
         .iterator();
     if (LOG.isTraceEnabled()) {
       LOG.trace("openFileMap size:" + size());
     }

     while (it.hasNext()) {
       Entry<FileHandle, OpenFileCtx> pairs = it.next();
       FileHandle handle = pairs.getKey();
       OpenFileCtx ctx = pairs.getValue();
       if (!ctx.streamCleanup(handle, streamTimeout)) {
         continue;
       }

       // Check it again inside lock before removing
       synchronized (this) {
         OpenFileCtx ctx2 = openFileMap.get(handle);
         if (ctx2 != null) {
           if (ctx2.streamCleanup(handle, streamTimeout)) {
             openFileMap.remove(handle);
             if (LOG.isDebugEnabled()) {
               LOG.debug("After remove stream " + handle.dumpFileHandle()
                   + ", the stream number:" + size());
             }
             ctxToRemove.add(ctx2);
           }
         }
       }
     }

     // Invoke the cleanup outside the lock
     for (OpenFileCtx ofc : ctxToRemove) {
       ofc.cleanup();
     }
   }

   OpenFileCtx get(FileHandle key) {
     return openFileMap.get(key);
   }

   int size() {
     return openFileMap.size();
   }

   void start() {
     streamMonitor.start();
   }

   // Evict all entries
   void cleanAll() {
     ArrayList<OpenFileCtx> cleanedContext = new ArrayList<OpenFileCtx>();
     synchronized (this) {
       Iterator<Entry<FileHandle, OpenFileCtx>> it = openFileMap.entrySet()
           .iterator();
       if (LOG.isTraceEnabled()) {
         LOG.trace("openFileMap size:" + size());
       }

       while (it.hasNext()) {
         Entry<FileHandle, OpenFileCtx> pairs = it.next();
         OpenFileCtx ctx = pairs.getValue();
         it.remove();
         cleanedContext.add(ctx);
       }
     }

     // Invoke the cleanup outside the lock
     for (OpenFileCtx ofc : cleanedContext) {
       ofc.cleanup();
     }
   }

   void shutdown() {
     // stop the dump thread
     if (streamMonitor.isAlive()) {
       streamMonitor.shouldRun(false);
       streamMonitor.interrupt();
       try {
         streamMonitor.join(3000);
       } catch (InterruptedException ignored) {
       }
     }

     cleanAll();
   }

   /**
    * StreamMonitor wakes up periodically to find and closes idle streams.
    */
   class StreamMonitor extends Daemon {
     private final static int rotation = 5 * 1000; // 5 seconds
     private long lastWakeupTime = 0;
     private boolean shouldRun = true;

     void shouldRun(boolean shouldRun) {
       this.shouldRun = shouldRun;
     }

     @Override
     public void run() {
       while (shouldRun) {
         scan(streamTimeout);

         // Check if it can sleep
         try {
           long workedTime = Time.monotonicNow() - lastWakeupTime;
           if (workedTime < rotation) {
             if (LOG.isTraceEnabled()) {
               LOG.trace("StreamMonitor can still have a sleep:"
                   + ((rotation - workedTime) / 1000));
             }
             Thread.sleep(rotation - workedTime);
           }
           lastWakeupTime = Time.monotonicNow();

         } catch (InterruptedException e) {
           LOG.info("StreamMonitor got interrupted");
           return;
         }
       }
     }
   }
 }
	/**
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF 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.apache.hadoop.hdfs.nfs.nfs3;

	import java.util.ArrayList;
	import java.util.Iterator;
	import java.util.Map.Entry;
	import java.util.concurrent.ConcurrentMap;

	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;
	import org.apache.hadoop.hdfs.nfs.conf.NfsConfigKeys;
	import org.apache.hadoop.hdfs.nfs.conf.NfsConfiguration;
	import org.apache.hadoop.nfs.nfs3.FileHandle;
	import org.apache.hadoop.util.Daemon;
	import org.apache.hadoop.util.Time;

	import com.google.common.annotations.VisibleForTesting;
	import com.google.common.base.Preconditions;
	import com.google.common.collect.Maps;

	/**
	* A cache saves OpenFileCtx objects for different users. Each cache entry is
	* used to maintain the writing context for a single file.
	*/
	class OpenFileCtxCache {
	private static final Logger LOG =
	LoggerFactory.getLogger(OpenFileCtxCache.class);
	// Insert and delete with openFileMap are synced
	private final ConcurrentMap<FileHandle, OpenFileCtx> openFileMap = Maps
	.newConcurrentMap();

	private final int maxStreams;
	private final long streamTimeout;
	private final StreamMonitor streamMonitor;

	OpenFileCtxCache(NfsConfiguration config, long streamTimeout) {
	maxStreams = config.getInt(NfsConfigKeys.DFS_NFS_MAX_OPEN_FILES_KEY,
	NfsConfigKeys.DFS_NFS_MAX_OPEN_FILES_DEFAULT);
	LOG.info("Maximum open streams is " + maxStreams);
	this.streamTimeout = streamTimeout;
	streamMonitor = new StreamMonitor();
	}

	/**
	* The entry to be evicted is based on the following rules:<br>
	* 1. if the OpenFileCtx has any pending task, it will not be chosen.<br>
	* 2. if there is inactive OpenFileCtx, the first found one is to evict. <br>
	* 3. For OpenFileCtx entries don't belong to group 1 or 2, the idlest one
	* is select. If it's idle longer than OUTPUT_STREAM_TIMEOUT_MIN_DEFAULT, it
	* will be evicted. Otherwise, the whole eviction request is failed.
	*/
	@VisibleForTesting
	Entry<FileHandle, OpenFileCtx> getEntryToEvict() {
	Iterator<Entry<FileHandle, OpenFileCtx>> it = openFileMap.entrySet()
	.iterator();
	if (LOG.isTraceEnabled()) {
	LOG.trace("openFileMap size:" + size());
	}

	Entry<FileHandle, OpenFileCtx> idlest = null;

	while (it.hasNext()) {
	Entry<FileHandle, OpenFileCtx> pairs = it.next();
	OpenFileCtx ctx = pairs.getValue();
	if (!ctx.getActiveState()) {
	if (LOG.isDebugEnabled()) {
	LOG.debug("Got one inactive stream: " + ctx);
	}
	return pairs;
	}
	if (ctx.hasPendingWork()) {
	// Always skip files with pending work.
	continue;
	}
	if (idlest == null) {
	idlest = pairs;
	} else {
	if (ctx.getLastAccessTime() < idlest.getValue().getLastAccessTime()) {
	idlest = pairs;
	}
	}
	}

	if (idlest == null) {
	LOG.warn("No eviction candidate. All streams have pending work.");
	return null;
	} else {
	long idleTime = Time.monotonicNow()
	- idlest.getValue().getLastAccessTime();
	if (idleTime < NfsConfigKeys.DFS_NFS_STREAM_TIMEOUT_MIN_DEFAULT) {
	if (LOG.isDebugEnabled()) {
	LOG.debug("idlest stream's idle time:" + idleTime);
	}
	LOG.warn("All opened streams are busy, can't remove any from cache.");
	return null;
	} else {
	return idlest;
	}
	}
	}

	boolean put(FileHandle h, OpenFileCtx context) {
	OpenFileCtx toEvict = null;
	synchronized (this) {
	Preconditions.checkState(size() <= this.maxStreams,
	"stream cache size " + size() + " is larger than maximum" + this
	.maxStreams);
	if (size() == this.maxStreams) {
	Entry<FileHandle, OpenFileCtx> pairs = getEntryToEvict();
	if (pairs ==null) {
	return false;
	} else {
	if (LOG.isDebugEnabled()) {
	LOG.debug("Evict stream ctx: " + pairs.getValue());
	}
	toEvict = openFileMap.remove(pairs.getKey());
	Preconditions.checkState(toEvict == pairs.getValue(),
	"The deleted entry is not the same as odlest found.");
	}
	}
	openFileMap.put(h, context);
	}

	// Cleanup the old stream outside the lock
	if (toEvict != null) {
	toEvict.cleanup();
	}
	return true;
	}

	@VisibleForTesting
	void scan(long streamTimeout) {
	ArrayList<OpenFileCtx> ctxToRemove = new ArrayList<OpenFileCtx>();
	Iterator<Entry<FileHandle, OpenFileCtx>> it = openFileMap.entrySet()
	.iterator();
	if (LOG.isTraceEnabled()) {
	LOG.trace("openFileMap size:" + size());
	}

	while (it.hasNext()) {
	Entry<FileHandle, OpenFileCtx> pairs = it.next();
	FileHandle handle = pairs.getKey();
	OpenFileCtx ctx = pairs.getValue();
	if (!ctx.streamCleanup(handle, streamTimeout)) {
	continue;
	}

	// Check it again inside lock before removing
	synchronized (this) {
	OpenFileCtx ctx2 = openFileMap.get(handle);
	if (ctx2 != null) {
	if (ctx2.streamCleanup(handle, streamTimeout)) {
	openFileMap.remove(handle);
	if (LOG.isDebugEnabled()) {
	LOG.debug("After remove stream " + handle.dumpFileHandle()
	+ ", the stream number:" + size());
	}
	ctxToRemove.add(ctx2);
	}
	}
	}
	}

	// Invoke the cleanup outside the lock
	for (OpenFileCtx ofc : ctxToRemove) {
	ofc.cleanup();
	}
	}

	OpenFileCtx get(FileHandle key) {
	return openFileMap.get(key);
	}

	int size() {
	return openFileMap.size();
	}

	void start() {
	streamMonitor.start();
	}

	// Evict all entries
	void cleanAll() {
	ArrayList<OpenFileCtx> cleanedContext = new ArrayList<OpenFileCtx>();
	synchronized (this) {
	Iterator<Entry<FileHandle, OpenFileCtx>> it = openFileMap.entrySet()
	.iterator();
	if (LOG.isTraceEnabled()) {
	LOG.trace("openFileMap size:" + size());
	}

	while (it.hasNext()) {
	Entry<FileHandle, OpenFileCtx> pairs = it.next();
	OpenFileCtx ctx = pairs.getValue();
	it.remove();
	cleanedContext.add(ctx);
	}
	}

	// Invoke the cleanup outside the lock
	for (OpenFileCtx ofc : cleanedContext) {
	ofc.cleanup();
	}
	}

	void shutdown() {
	// stop the dump thread
	if (streamMonitor.isAlive()) {
	streamMonitor.shouldRun(false);
	streamMonitor.interrupt();
	try {
	streamMonitor.join(3000);
	} catch (InterruptedException ignored) {
	}
	}

	cleanAll();
	}

	/**
	* StreamMonitor wakes up periodically to find and closes idle streams.
	*/
	class StreamMonitor extends Daemon {
	private final static int rotation = 5 * 1000; // 5 seconds
	private long lastWakeupTime = 0;
	private boolean shouldRun = true;

	void shouldRun(boolean shouldRun) {
	this.shouldRun = shouldRun;
	}

	@Override
	public void run() {
	while (shouldRun) {
	scan(streamTimeout);

	// Check if it can sleep
	try {
	long workedTime = Time.monotonicNow() - lastWakeupTime;
	if (workedTime < rotation) {
	if (LOG.isTraceEnabled()) {
	LOG.trace("StreamMonitor can still have a sleep:"
	+ ((rotation - workedTime) / 1000));
	}
	Thread.sleep(rotation - workedTime);
	}
	lastWakeupTime = Time.monotonicNow();

	} catch (InterruptedException e) {
	LOG.info("StreamMonitor got interrupted");
	return;
	}
	}
	}
	}
	}