HDFS-10987. Make Decommission less expensive when lot of blocks present. Contributed by Brahma Reddy Battula.
Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/332a61fd Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/332a61fd Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/332a61fd Branch: refs/heads/HDFS-10285 Commit: 332a61fd74fd2a9874319232c583ab5d2c53ff03 Parents: fdce515 Author: Kihwal Lee <kih...@apache.org> Authored: Thu Oct 13 13:52:49 2016 -0500 Committer: Kihwal Lee <kih...@apache.org> Committed: Thu Oct 13 13:52:49 2016 -0500 ---------------------------------------------------------------------- .../blockmanagement/DecommissionManager.java | 29 +++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hadoop/blob/332a61fd/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DecommissionManager.java ---------------------------------------------------------------------- diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DecommissionManager.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DecommissionManager.java index 6436fab..87b36da 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DecommissionManager.java +++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DecommissionManager.java @@ -389,6 +389,10 @@ public class DecommissionManager { */ private int numBlocksChecked = 0; /** + * The number of blocks checked after (re)holding lock. + */ + private int numBlocksCheckedPerLock = 0; + /** * The number of nodes that have been checked on this tick. Used for * statistics. */ @@ -418,6 +422,7 @@ public class DecommissionManager { } // Reset the checked count at beginning of each iteration numBlocksChecked = 0; + numBlocksCheckedPerLock = 0; numNodesChecked = 0; // Check decom progress namesystem.writeLock(); @@ -451,7 +456,8 @@ public class DecommissionManager { iterkey).iterator(); final LinkedList<DatanodeDescriptor> toRemove = new LinkedList<>(); - while (it.hasNext() && !exceededNumBlocksPerCheck()) { + while (it.hasNext() && !exceededNumBlocksPerCheck() && namesystem + .isRunning()) { numNodesChecked++; final Map.Entry<DatanodeDescriptor, AbstractList<BlockInfo>> entry = it.next(); @@ -577,7 +583,28 @@ public class DecommissionManager { int decommissionOnlyReplicas = 0; int lowRedundancyInOpenFiles = 0; while (it.hasNext()) { + if (insufficientList == null + && numBlocksCheckedPerLock >= numBlocksPerCheck) { + // During fullscan insufficientlyReplicated will NOT be null, iterator + // will be DN's iterator. So should not yield lock, otherwise + // ConcurrentModificationException could occur. + // Once the fullscan done, iterator will be a copy. So can yield the + // lock. + // Yielding is required in case of block number is greater than the + // configured per-iteration-limit. + namesystem.writeUnlock(); + try { + LOG.debug("Yielded lock during decommission check"); + Thread.sleep(0, 500); + } catch (InterruptedException ignored) { + return; + } + // reset + numBlocksCheckedPerLock = 0; + namesystem.writeLock(); + } numBlocksChecked++; + numBlocksCheckedPerLock++; final BlockInfo block = it.next(); // Remove the block from the list if it's no longer in the block map, // e.g. the containing file has been deleted --------------------------------------------------------------------- To unsubscribe, e-mail: common-commits-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-commits-h...@hadoop.apache.org