HDFS-10690. Optimize insertion/removal of replica in ShortCircuitCache. Contributed by Fenghua Hu.

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/shortcircuit/ShortCircuitCache.java

@@ -26,13 +26,14 @@ import java.nio.MappedByteBuffer;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Map.Entry;
-import java.util.TreeMap;
+import java.util.NoSuchElementException;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.Condition;
 import java.util.concurrent.locks.ReentrantLock;
 
+import org.apache.commons.collections.map.LinkedMap;
 import org.apache.commons.lang.mutable.MutableBoolean;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.hdfs.ExtendedBlockId;
@@ -107,16 +108,20 @@ public class ShortCircuitCache implements Closeable {
 
         int numDemoted = demoteOldEvictableMmaped(curMs);
         int numPurged = 0;
-        Long evictionTimeNs = (long) 0;
+        Long evictionTimeNs;
         while (true) {
-          Entry<Long, ShortCircuitReplica> entry =
-              evictable.ceilingEntry(evictionTimeNs);
-          if (entry == null) break;
-          evictionTimeNs = entry.getKey();
+          Object eldestKey;
+          try {
+            eldestKey = evictable.firstKey();
+          } catch (NoSuchElementException e) {
+            break;
+          }
+          evictionTimeNs = (Long)eldestKey;
           long evictionTimeMs =
               TimeUnit.MILLISECONDS.convert(evictionTimeNs, TimeUnit.NANOSECONDS);
           if (evictionTimeMs + maxNonMmappedEvictableLifespanMs >= curMs) break;
-          ShortCircuitReplica replica = entry.getValue();
+          ShortCircuitReplica replica = (ShortCircuitReplica)evictable.get(
+              eldestKey);
           if (LOG.isTraceEnabled()) {
             LOG.trace("CacheCleaner: purging " + replica + ": " +
                 StringUtils.getStackTrace(Thread.currentThread()));
@@ -263,11 +268,11 @@ public class ShortCircuitCache implements Closeable {
   private CacheCleaner cacheCleaner;
 
   /**
-   * Tree of evictable elements.
+   * LinkedMap of evictable elements.
    *
    * Maps (unique) insertion time in nanoseconds to the element.
    */
-  private final TreeMap<Long, ShortCircuitReplica> evictable = new TreeMap<>();
+  private final LinkedMap evictable = new LinkedMap();
 
   /**
    * Maximum total size of the cache, including both mmapped and
@@ -281,12 +286,11 @@ public class ShortCircuitCache implements Closeable {
   private long maxNonMmappedEvictableLifespanMs;
 
   /**
-   * Tree of mmaped evictable elements.
+   * LinkedMap of mmaped evictable elements.
    *
    * Maps (unique) insertion time in nanoseconds to the element.
    */
-  private final TreeMap<Long, ShortCircuitReplica> evictableMmapped =
-      new TreeMap<>();
+  private final LinkedMap evictableMmapped = new LinkedMap();
 
   /**
    * Maximum number of mmaped evictable elements.
@@ -482,13 +486,16 @@ public class ShortCircuitCache implements Closeable {
   private int demoteOldEvictableMmaped(long now) {
     int numDemoted = 0;
     boolean needMoreSpace = false;
-    Long evictionTimeNs = (long) 0;
+    Long evictionTimeNs;
 
     while (true) {
-      Entry<Long, ShortCircuitReplica> entry =
-          evictableMmapped.ceilingEntry(evictionTimeNs);
-      if (entry == null) break;
-      evictionTimeNs = entry.getKey();
+      Object eldestKey;
+      try {
+        eldestKey = evictableMmapped.firstKey();
+      } catch (NoSuchElementException e) {
+        break;
+      }
+      evictionTimeNs = (Long)eldestKey;
       long evictionTimeMs =
           TimeUnit.MILLISECONDS.convert(evictionTimeNs, TimeUnit.NANOSECONDS);
       if (evictionTimeMs + maxEvictableMmapedLifespanMs >= now) {
@@ -497,7 +504,8 @@ public class ShortCircuitCache implements Closeable {
         }
         needMoreSpace = true;
       }
-      ShortCircuitReplica replica = entry.getValue();
+      ShortCircuitReplica replica = (ShortCircuitReplica)evictableMmapped.get(
+          eldestKey);
       if (LOG.isTraceEnabled()) {
         String rationale = needMoreSpace ? "because we need more space" :
             "because it's too old";
@@ -527,10 +535,15 @@ public class ShortCircuitCache implements Closeable {
         return;
       }
       ShortCircuitReplica replica;
-      if (evictableSize == 0) {
-        replica = evictableMmapped.firstEntry().getValue();
-      } else {
-        replica = evictable.firstEntry().getValue();
+      try {
+        if (evictableSize == 0) {
+          replica = (ShortCircuitReplica)evictableMmapped.get(evictableMmapped
+              .firstKey());
+        } else {
+          replica = (ShortCircuitReplica)evictable.get(evictable.firstKey());
+        }
+      } catch (NoSuchElementException e) {
+        break;
       }
       if (LOG.isTraceEnabled()) {
         LOG.trace(this + ": trimEvictionMaps is purging " + replica +
@@ -573,10 +586,11 @@ public class ShortCircuitCache implements Closeable {
    * @param map       The map to remove it from.
    */
   private void removeEvictable(ShortCircuitReplica replica,
-      TreeMap<Long, ShortCircuitReplica> map) {
+      LinkedMap map) {
     Long evictableTimeNs = replica.getEvictableTimeNs();
     Preconditions.checkNotNull(evictableTimeNs);
-    ShortCircuitReplica removed = map.remove(evictableTimeNs);
+    ShortCircuitReplica removed = (ShortCircuitReplica)map.remove(
+        evictableTimeNs);
     Preconditions.checkState(removed == replica,
         "failed to make %s unevictable", replica);
     replica.setEvictableTimeNs(null);
@@ -593,7 +607,7 @@ public class ShortCircuitCache implements Closeable {
    * @param map              The map to insert it into.
    */
   private void insertEvictable(Long evictionTimeNs,
-      ShortCircuitReplica replica, TreeMap<Long, ShortCircuitReplica> map) {
+      ShortCircuitReplica replica, LinkedMap map) {
     while (map.containsKey(evictionTimeNs)) {
       evictionTimeNs++;
     }
@@ -861,14 +875,22 @@ public class ShortCircuitCache implements Closeable {
       IOUtilsClient.cleanup(LOG, cacheCleaner);
       // Purge all replicas.
       while (true) {
-        Entry<Long, ShortCircuitReplica> entry = evictable.firstEntry();
-        if (entry == null) break;
-        purge(entry.getValue());
+        Object eldestKey;
+        try {
+          eldestKey = evictable.firstKey();
+        } catch (NoSuchElementException e) {
+          break;
+        }
+        purge((ShortCircuitReplica)evictable.get(eldestKey));
       }
       while (true) {
-        Entry<Long, ShortCircuitReplica> entry = evictableMmapped.firstEntry();
-        if (entry == null) break;
-        purge(entry.getValue());
+        Object eldestKey;
+        try {
+          eldestKey = evictableMmapped.firstKey();
+        } catch (NoSuchElementException e) {
+          break;
+        }
+        purge((ShortCircuitReplica)evictableMmapped.get(eldestKey));
       }
     } finally {
       lock.unlock();
@@ -909,8 +931,8 @@ public class ShortCircuitCache implements Closeable {
     void visit(int numOutstandingMmaps,
         Map<ExtendedBlockId, ShortCircuitReplica> replicas,
         Map<ExtendedBlockId, InvalidToken> failedLoads,
-        Map<Long, ShortCircuitReplica> evictable,
-        Map<Long, ShortCircuitReplica> evictableMmapped);
+        LinkedMap evictable,
+        LinkedMap evictableMmapped);
   }
 
   @VisibleForTesting // ONLY for testing

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/fs/TestEnhancedByteBufferAccess.java

@@ -34,6 +34,7 @@ import java.util.Map;
 import java.util.Random;
 import java.util.concurrent.TimeoutException;
 
+import org.apache.commons.collections.map.LinkedMap;
 import org.apache.commons.lang.SystemUtils;
 import org.apache.commons.lang.mutable.MutableBoolean;
 import org.apache.commons.logging.Log;
@@ -307,8 +308,8 @@ public class TestEnhancedByteBufferAccess {
     public void visit(int numOutstandingMmaps,
         Map<ExtendedBlockId, ShortCircuitReplica> replicas,
         Map<ExtendedBlockId, InvalidToken> failedLoads,
-        Map<Long, ShortCircuitReplica> evictable,
-        Map<Long, ShortCircuitReplica> evictableMmapped) {
+        LinkedMap evictable,
+        LinkedMap evictableMmapped) {
       if (expectedNumOutstandingMmaps >= 0) {
         Assert.assertEquals(expectedNumOutstandingMmaps, numOutstandingMmaps);
       }
@@ -373,8 +374,8 @@ public class TestEnhancedByteBufferAccess {
       public void visit(int numOutstandingMmaps,
           Map<ExtendedBlockId, ShortCircuitReplica> replicas,
           Map<ExtendedBlockId, InvalidToken> failedLoads, 
-          Map<Long, ShortCircuitReplica> evictable,
-          Map<Long, ShortCircuitReplica> evictableMmapped) {
+          LinkedMap evictable,
+          LinkedMap evictableMmapped) {
         ShortCircuitReplica replica = replicas.get(
             new ExtendedBlockId(firstBlock.getBlockId(), firstBlock.getBlockPoolId()));
         Assert.assertNotNull(replica);
@@ -410,8 +411,8 @@ public class TestEnhancedByteBufferAccess {
           public void visit(int numOutstandingMmaps,
               Map<ExtendedBlockId, ShortCircuitReplica> replicas,
               Map<ExtendedBlockId, InvalidToken> failedLoads,
-              Map<Long, ShortCircuitReplica> evictable,
-              Map<Long, ShortCircuitReplica> evictableMmapped) {
+              LinkedMap evictable,
+              LinkedMap evictableMmapped) {
             finished.setValue(evictableMmapped.isEmpty());
           }
         });
@@ -685,8 +686,8 @@ public class TestEnhancedByteBufferAccess {
           public void visit(int numOutstandingMmaps,
               Map<ExtendedBlockId, ShortCircuitReplica> replicas,
               Map<ExtendedBlockId, InvalidToken> failedLoads,
-              Map<Long, ShortCircuitReplica> evictable,
-              Map<Long, ShortCircuitReplica> evictableMmapped) {
+              LinkedMap evictable,
+              LinkedMap evictableMmapped) {
             Assert.assertEquals(expectedOutstandingMmaps, numOutstandingMmaps);
             ShortCircuitReplica replica =
                 replicas.get(ExtendedBlockId.fromExtendedBlock(block));

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/shortcircuit/TestShortCircuitCache.java

@@ -34,6 +34,7 @@ import java.util.Iterator;
 import java.util.Map;
 import java.util.concurrent.TimeoutException;
 
+import org.apache.commons.collections.map.LinkedMap;
 import org.apache.commons.lang.mutable.MutableBoolean;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -502,8 +503,8 @@ public class TestShortCircuitCache {
       public void visit(int numOutstandingMmaps,
           Map<ExtendedBlockId, ShortCircuitReplica> replicas,
           Map<ExtendedBlockId, InvalidToken> failedLoads,
-          Map<Long, ShortCircuitReplica> evictable,
-          Map<Long, ShortCircuitReplica> evictableMmapped) {
+          LinkedMap evictable,
+          LinkedMap evictableMmapped) {
         ShortCircuitReplica replica = replicas.get(
             ExtendedBlockId.fromExtendedBlock(block));
         Assert.assertNotNull(replica);
@@ -518,8 +519,8 @@ public class TestShortCircuitCache {
       public void visit(int numOutstandingMmaps,
           Map<ExtendedBlockId, ShortCircuitReplica> replicas,
           Map<ExtendedBlockId, InvalidToken> failedLoads,
-          Map<Long, ShortCircuitReplica> evictable,
-          Map<Long, ShortCircuitReplica> evictableMmapped) {
+          LinkedMap evictable,
+          LinkedMap evictableMmapped) {
         ShortCircuitReplica replica = replicas.get(
             ExtendedBlockId.fromExtendedBlock(block));
         Assert.assertNotNull(replica);