HDFS-14458. Report pmem stats to namenode. Contributed by Feilong He.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/MemoryCacheStats.java → hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/CacheStats.java

@@ -27,7 +27,7 @@ import com.google.common.annotations.VisibleForTesting;
 /**
  * Keeps statistics for the memory cache.
  */
-class MemoryCacheStats {
+class CacheStats {
 
   /**
    * The approximate amount of cache space in use.
@@ -47,7 +47,7 @@ class MemoryCacheStats {
    */
   private final long maxBytes;
 
-  MemoryCacheStats(long maxBytes) {
+  CacheStats(long maxBytes) {
     this.usedBytesCount = new UsedBytesCount();
     this.maxBytes = maxBytes;
   }
@@ -81,7 +81,7 @@ class MemoryCacheStats {
   private class UsedBytesCount {
     private final AtomicLong usedBytes = new AtomicLong(0);
 
-    private MemoryCacheStats.PageRounder rounder = new PageRounder();
+    private CacheStats.PageRounder rounder = new PageRounder();
 
     /**
      * Try to reserve more bytes.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetCache.java

@@ -23,7 +23,6 @@ import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_CACHE_REVOCATION
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_CACHE_REVOCATION_POLLING_MS;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_CACHE_REVOCATION_POLLING_MS_DEFAULT;
 
-import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
 
@@ -137,7 +136,7 @@ public class FsDatasetCache {
    */
   private final MappableBlockLoader cacheLoader;
 
-  private final MemoryCacheStats memCacheStats;
+  private final CacheStats memCacheStats;
 
   /**
    * Number of cache commands that could not be completed successfully
@@ -178,30 +177,17 @@ public class FsDatasetCache {
               ".  Reconfigure this to " + minRevocationPollingMs);
     }
     this.revocationPollingMs = confRevocationPollingMs;
-    // Both lazy writer and read cache are sharing this statistics.
-    this.memCacheStats = new MemoryCacheStats(
-        dataset.datanode.getDnConf().getMaxLockedMemory());
 
     this.cacheLoader = MappableBlockLoaderFactory.createCacheLoader(
         this.getDnConf());
-    cacheLoader.initialize(this);
-  }
-
-  /**
-   * Check if pmem cache is enabled.
-   */
-  private boolean isPmemCacheEnabled() {
-    return !cacheLoader.isTransientCache();
+    // Both lazy writer and read cache are sharing this statistics.
+    this.memCacheStats = cacheLoader.initialize(this.getDnConf());
   }
 
   DNConf getDnConf() {
     return this.dataset.datanode.getDnConf();
   }
 
-  MemoryCacheStats getMemCacheStats() {
-    return memCacheStats;
-  }
-
   /**
    * Get the cache path if the replica is cached into persistent memory.
    */
@@ -557,37 +543,32 @@ public class FsDatasetCache {
   /**
    * Get the approximate amount of DRAM cache space used.
    */
-  public long getCacheUsed() {
+  public long getMemCacheUsed() {
     return memCacheStats.getCacheUsed();
   }
 
   /**
-   * Get the approximate amount of persistent memory cache space used.
-   * TODO: advertise this metric to NameNode by FSDatasetMBean
+   * Get the approximate amount of cache space used either on DRAM or
+   * on persistent memory.
+   * @return
    */
-  public long getPmemCacheUsed() {
-    if (isPmemCacheEnabled()) {
-      return cacheLoader.getCacheUsed();
-    }
-    return 0;
+  public long getCacheUsed() {
+    return cacheLoader.getCacheUsed();
   }
 
   /**
-   * Get the maximum amount of bytes we can cache on DRAM.  This is a constant.
+   * Get the maximum amount of bytes we can cache on DRAM. This is a constant.
    */
-  public long getCacheCapacity() {
+  public long getMemCacheCapacity() {
     return memCacheStats.getCacheCapacity();
   }
 
   /**
-   * Get cache capacity of persistent memory.
-   * TODO: advertise this metric to NameNode by FSDatasetMBean
+   * Get the maximum amount of bytes we can cache either on DRAM or
+   * on persistent memory. This is a constant.
    */
-  public long getPmemCacheCapacity() {
-    if (isPmemCacheEnabled()) {
-      return cacheLoader.getCacheCapacity();
-    }
-    return 0;
+  public long getCacheCapacity() {
+    return cacheLoader.getCacheCapacity();
   }
 
   public long getNumBlocksFailedToCache() {
@@ -608,11 +589,6 @@ public class FsDatasetCache {
     return (val != null) && val.state.shouldAdvertise();
   }
 
-  @VisibleForTesting
-  MappableBlockLoader getCacheLoader() {
-    return cacheLoader;
-  }
-
   /**
    * This method can be executed during DataNode shutdown.
    */

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java

@@ -3164,10 +3164,10 @@ class FsDatasetImpl implements FsDatasetSpi<FsVolumeImpl> {
     public void evictBlocks(long bytesNeeded) throws IOException {
       int iterations = 0;
 
-      final long cacheCapacity = cacheManager.getCacheCapacity();
+      final long cacheCapacity = cacheManager.getMemCacheCapacity();
 
       while (iterations++ < MAX_BLOCK_EVICTIONS_PER_ITERATION &&
-             (cacheCapacity - cacheManager.getCacheUsed()) < bytesNeeded) {
+             (cacheCapacity - cacheManager.getMemCacheUsed()) < bytesNeeded) {
         RamDiskReplica replicaState = ramDiskReplicaTracker.getNextCandidateForEviction();
 
         if (replicaState == null) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/MappableBlockLoader.java

@@ -24,6 +24,7 @@ import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.hdfs.ExtendedBlockId;
 import org.apache.hadoop.hdfs.server.datanode.BlockMetadataHeader;
+import org.apache.hadoop.hdfs.server.datanode.DNConf;
 import org.apache.hadoop.util.DataChecksum;
 
 import java.io.BufferedInputStream;
@@ -43,7 +44,7 @@ public abstract class MappableBlockLoader {
   /**
    * Initialize a specific MappableBlockLoader.
    */
-  abstract void initialize(FsDatasetCache cacheManager) throws IOException;
+  abstract CacheStats initialize(DNConf dnConf) throws IOException;
 
   /**
    * Load the block.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/MemoryMappableBlockLoader.java

@@ -22,6 +22,7 @@ import org.apache.commons.io.IOUtils;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.hdfs.ExtendedBlockId;
+import org.apache.hadoop.hdfs.server.datanode.DNConf;
 import org.apache.hadoop.io.nativeio.NativeIO;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -39,12 +40,13 @@ import java.nio.channels.FileChannel;
 public class MemoryMappableBlockLoader extends MappableBlockLoader {
   private static final Logger LOG =
       LoggerFactory.getLogger(MemoryMappableBlockLoader.class);
-  private MemoryCacheStats memCacheStats;
+  private CacheStats memCacheStats;
 
   @Override
-  void initialize(FsDatasetCache cacheManager) throws IOException {
+  CacheStats initialize(DNConf dnConf) throws IOException {
     LOG.info("Initializing cache loader: MemoryMappableBlockLoader.");
-    this.memCacheStats = cacheManager.getMemCacheStats();
+    this.memCacheStats = new CacheStats(dnConf.getMaxLockedMemory());
+    return memCacheStats;
   }
 
   /**

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/NativePmemMappableBlockLoader.java

@@ -24,6 +24,7 @@ import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.hdfs.ExtendedBlockId;
 import org.apache.hadoop.hdfs.server.datanode.BlockMetadataHeader;
+import org.apache.hadoop.hdfs.server.datanode.DNConf;
 import org.apache.hadoop.io.nativeio.NativeIO;
 import org.apache.hadoop.io.nativeio.NativeIO.POSIX;
 import org.apache.hadoop.util.DataChecksum;
@@ -47,8 +48,8 @@ public class NativePmemMappableBlockLoader extends PmemMappableBlockLoader {
       LoggerFactory.getLogger(NativePmemMappableBlockLoader.class);
 
   @Override
-  void initialize(FsDatasetCache cacheManager) throws IOException {
-    super.initialize(cacheManager);
+  CacheStats initialize(DNConf dnConf) throws IOException {
+    return super.initialize(dnConf);
   }
 
   /**

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/PmemMappableBlockLoader.java

@@ -42,11 +42,16 @@ public class PmemMappableBlockLoader extends MappableBlockLoader {
   private PmemVolumeManager pmemVolumeManager;
 
   @Override
-  void initialize(FsDatasetCache cacheManager) throws IOException {
+  CacheStats initialize(DNConf dnConf) throws IOException {
     LOG.info("Initializing cache loader: " + this.getClass().getName());
-    DNConf dnConf = cacheManager.getDnConf();
     PmemVolumeManager.init(dnConf.getPmemVolumes());
     pmemVolumeManager = PmemVolumeManager.getInstance();
+    // The configuration for max locked memory is shaded.
+    LOG.info("Persistent memory is used for caching data instead of " +
+        "DRAM. Max locked memory is set to zero to disable DRAM cache");
+    // TODO: PMem is not supporting Lazy Writer now, will refine this stats
+    // while implementing it.
+    return new CacheStats(0L);
   }
 
   /**

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestCacheByPmemMappableBlockLoader.java

@@ -84,7 +84,6 @@ public class TestCacheByPmemMappableBlockLoader {
   private static DistributedFileSystem fs;
   private static DataNode dn;
   private static FsDatasetCache cacheManager;
-  private static PmemMappableBlockLoader cacheLoader;
   /**
    * Used to pause DN BPServiceActor threads. BPSA threads acquire the
    * shared read lock. The test acquires the write lock for exclusive access.
@@ -131,8 +130,6 @@ public class TestCacheByPmemMappableBlockLoader {
         DFSConfigKeys.DFS_NAMENODE_PATH_BASED_CACHE_REFRESH_INTERVAL_MS, 100);
     conf.setLong(DFSConfigKeys.DFS_CACHEREPORT_INTERVAL_MSEC_KEY, 500);
     conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, BLOCK_SIZE);
-    conf.setLong(DFSConfigKeys.DFS_DATANODE_MAX_LOCKED_MEMORY_KEY,
-        CACHE_CAPACITY);
     conf.setLong(DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_KEY, 1);
     conf.setInt(DFS_DATANODE_FSDATASETCACHE_MAX_THREADS_PER_VOLUME_KEY, 10);
 
@@ -153,7 +150,6 @@ public class TestCacheByPmemMappableBlockLoader {
     fs = cluster.getFileSystem();
     dn = cluster.getDataNodes().get(0);
     cacheManager = ((FsDatasetImpl) dn.getFSDataset()).cacheManager;
-    cacheLoader = (PmemMappableBlockLoader) cacheManager.getCacheLoader();
   }
 
   @After
@@ -216,7 +212,9 @@ public class TestCacheByPmemMappableBlockLoader {
         Ints.checkedCast(CACHE_CAPACITY / BLOCK_SIZE);
     BlockReaderTestUtil.enableHdfsCachingTracing();
     Assert.assertEquals(0, CACHE_CAPACITY % BLOCK_SIZE);
-    assertEquals(CACHE_CAPACITY, cacheManager.getPmemCacheCapacity());
+    assertEquals(CACHE_CAPACITY, cacheManager.getCacheCapacity());
+    // DRAM cache is expected to be disabled.
+    assertEquals(0L, cacheManager.getMemCacheCapacity());
 
     final Path testFile = new Path("/testFile");
     final long testFileLen = maxCacheBlocksNum * BLOCK_SIZE;
@@ -246,7 +244,9 @@ public class TestCacheByPmemMappableBlockLoader {
     }, 1000, 30000);
 
     // The pmem cache space is expected to have been used up.
-    assertEquals(CACHE_CAPACITY, cacheManager.getPmemCacheUsed());
+    assertEquals(CACHE_CAPACITY, cacheManager.getCacheUsed());
+    // There should be no cache used on DRAM.
+    assertEquals(0L, cacheManager.getMemCacheUsed());
     Map<ExtendedBlockId, Byte> blockKeyToVolume =
         PmemVolumeManager.getInstance().getBlockKeyToVolume();
     // All block keys should be kept in blockKeyToVolume
@@ -318,7 +318,7 @@ public class TestCacheByPmemMappableBlockLoader {
     }, 1000, 30000);
 
     // It is expected that no pmem cache space is used.
-    assertEquals(0, cacheManager.getPmemCacheUsed());
+    assertEquals(0, cacheManager.getCacheUsed());
     // No record should be kept by blockKeyToVolume after testFile is uncached.
     assertEquals(blockKeyToVolume.size(), 0);
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestFsDatasetCache.java

@@ -63,7 +63,7 @@ import org.apache.hadoop.hdfs.server.datanode.DataNode;
 import org.apache.hadoop.hdfs.server.datanode.DataNodeFaultInjector;
 import org.apache.hadoop.hdfs.server.datanode.InternalDataNodeTestUtils;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
-import org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.MemoryCacheStats.PageRounder;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.CacheStats.PageRounder;
 import org.apache.hadoop.hdfs.server.namenode.FSImage;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.hdfs.server.protocol.BlockIdCommand;