Index: src/main/java/org/apache/jackrabbit/oak/plugins/segment/SegmentNodeStore.java
===================================================================
--- src/main/java/org/apache/jackrabbit/oak/plugins/segment/SegmentNodeStore.java	(revision 1712730)
+++ src/main/java/org/apache/jackrabbit/oak/plugins/segment/SegmentNodeStore.java	(working copy)
@@ -90,7 +90,7 @@
      * Only a single local commit is allowed at a time. When such
      * a commit is in progress, no external updates will be seen.
      */
-    private final Semaphore commitSemaphore = new Semaphore(1);
+    private final Semaphore commitSemaphore;
 
     private long maximumBackoff = MILLISECONDS.convert(10, SECONDS);
 
@@ -101,6 +101,12 @@
     private int checkpointsLockWaitTime = Integer.getInteger(
             "oak.checkpoints.lockWaitTime", 10);
 
+    /**
+     * Flag controlling the commit lock fairness
+     */
+    private boolean commitFairLock = Boolean
+            .getBoolean("oak.SegmentNodeStore.commitFairLock");
+
     @Nonnull
     public static SegmentNodeStoreBuilder newSegmentNodeStore(
             @Nonnull SegmentStore store) {
@@ -117,6 +123,7 @@
     }
 
     SegmentNodeStore(SegmentStore store, boolean internal) {
+        this.commitSemaphore = new Semaphore(1, commitFairLock);
         this.store = store;
         this.head = new AtomicReference<SegmentNodeState>(store.getHead());
         this.changeDispatcher = new ChangeDispatcher(getRoot());