--- a/src/share/vm/prims/whitebox.cpp	Mon Nov 10 17:14:59 2014 +0100
+++ b/src/share/vm/prims/whitebox.cpp	Wed Nov 05 08:22:17 2014 -0800
@@ -344,15 +344,6 @@
   return MemTracker::tracking_level() == NMT_detail;
 WB_END
 
-WB_ENTRY(void, WB_NMTOverflowHashBucket(JNIEnv* env, jobject o, jlong num))
-  address pc = (address)1;
-  for (jlong index = 0; index < num; index ++) {
-    NativeCallStack stack(&pc, 1);
-    os::malloc(0, mtTest, stack);
-    pc += MallocSiteTable::hash_buckets();
-  }
-WB_END
-
 WB_ENTRY(jboolean, WB_NMTChangeTrackingLevel(JNIEnv* env))
   // Test that we can downgrade NMT levels but not upgrade them.
   if (MemTracker::tracking_level() == NMT_off) {
@@ -383,6 +374,12 @@
     return MemTracker::tracking_level() == NMT_minimal;
   }
 WB_END
+
+WB_ENTRY(jint, WB_NMTGetHashSize(JNIEnv* env, jobject o))
+  int hash_size = MallocSiteTable::hash_buckets();
+  assert(hash_size > 0, "NMT hash_size should be > 0");
+  return (jint)hash_size;
+WB_END
 #endif // INCLUDE_NMT
 
 static jmethodID reflected_method_to_jmid(JavaThread* thread, JNIEnv* env, jobject method) {
@@ -981,9 +978,9 @@
   {CC"NMTCommitMemory",     CC"(JJ)V",                (void*)&WB_NMTCommitMemory    },
   {CC"NMTUncommitMemory",   CC"(JJ)V",                (void*)&WB_NMTUncommitMemory  },
   {CC"NMTReleaseMemory",    CC"(JJ)V",                (void*)&WB_NMTReleaseMemory   },
-  {CC"NMTOverflowHashBucket", CC"(J)V",               (void*)&WB_NMTOverflowHashBucket},
   {CC"NMTIsDetailSupported",CC"()Z",                  (void*)&WB_NMTIsDetailSupported},
   {CC"NMTChangeTrackingLevel", CC"()Z",               (void*)&WB_NMTChangeTrackingLevel},
+  {CC"NMTGetHashSize",      CC"()I",                  (void*)&WB_NMTGetHashSize     },
 #endif // INCLUDE_NMT
   {CC"deoptimizeAll",      CC"()V",                   (void*)&WB_DeoptimizeAll     },
   {CC"deoptimizeMethod",   CC"(Ljava/lang/reflect/Executable;Z)I",

--- a/test/TEST.ROOT	Mon Nov 10 17:14:59 2014 +0100
+++ b/test/TEST.ROOT	Wed Nov 05 08:22:17 2014 -0800
@@ -30,3 +30,4 @@
 keys=cte_test jcmd nmt regression gc stress
 
 groups=TEST.groups [closed/TEST.groups]
+requires.properties=sun.arch.data.model

--- a/test/runtime/NMT/MallocSiteHashOverflow.java	Mon Nov 10 17:14:59 2014 +0100
+++ b/test/runtime/NMT/MallocSiteHashOverflow.java	Wed Nov 05 08:22:17 2014 -0800
@@ -24,41 +24,56 @@
 /*
  * @test
  * @summary Test corner case that overflows malloc site hashtable bucket
+ * @requires sun.arch.data.model == "32"
  * @key nmt jcmd stress
  * @library /testlibrary /testlibrary/whitebox
- * @ignore - This test is disabled since it will stress NMT and timeout during normal testing
+ * @ignore 8062870
  * @build MallocSiteHashOverflow
  * @run main ClassFileInstaller sun.hotspot.WhiteBox
- * @run main/othervm/timeout=480 -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:NativeMemoryTracking=detail MallocSiteHashOverflow
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:NativeMemoryTracking=detail MallocSiteHashOverflow
  */
 
 import com.oracle.java.testlibrary.*;
 import sun.hotspot.WhiteBox;
 
 public class MallocSiteHashOverflow {
-    private static long K = 1024;
+
     public static void main(String args[]) throws Exception {
-        String vm_name = System.getProperty("java.vm.name");
 
+        // Size of entries based on malloc tracking header defined in mallocTracker.hpp
         // For 32-bit systems, create 257 malloc sites with the same hash bucket to overflow a hash bucket
-        // For 64-bit systems, create 64K + 1 malloc sites with the same hash bucket to overflow a hash bucket
         long entries = 257;
-        if (Platform.is64bit()) {
-            entries = 64 * K + 1;
-        }
 
         OutputAnalyzer output;
         WhiteBox wb = WhiteBox.getWhiteBox();
+        int MAX_HASH_SIZE = wb.NMTGetHashSize();
 
         // Grab my own PID
         String pid = Integer.toString(ProcessTools.getProcessId());
         ProcessBuilder pb = new ProcessBuilder();
 
-        wb.NMTOverflowHashBucket(entries);
-
-        // Run 'jcmd <pid> VM.native_memory summary'
+        // Verify that current tracking level is "detail"
         pb.command(new String[] { JDKToolFinder.getJDKTool("jcmd"), pid, "VM.native_memory", "statistics"});
         output = new OutputAnalyzer(pb.start());
-        output.shouldContain("Tracking level has been downgraded due to lack of resources");
+        output.shouldContain("Native Memory Tracking Statistics");
+
+        // Attempt to cause NMT to downgrade tracking level by allocating small amounts
+        // of memory with random pseudo call stack
+        int pc = 1;
+        for (int i = 0; i < entries; i++) {
+            long addr = wb.NMTMallocWithPseudoStack(1, pc);
+            if (addr == 0) {
+                throw new RuntimeException("NMTMallocWithPseudoStack: out of memory");
+            }
+            // We free memory here since it doesn't affect pseudo malloc alloc site hash table entries
+            wb.NMTFree(addr);
+            pc += MAX_HASH_SIZE;
+            if (i == entries) {
+                // Verify that tracking has been downgraded
+                pb.command(new String[] { JDKToolFinder.getJDKTool("jcmd"), pid, "VM.native_memory", "statistics"});
+                output = new OutputAnalyzer(pb.start());
+                output.shouldContain("Tracking level has been downgraded due to lack of resources");
+            }
+        }
     }
 }

--- a/test/testlibrary/whitebox/sun/hotspot/WhiteBox.java	Mon Nov 10 17:14:59 2014 +0100
+++ b/test/testlibrary/whitebox/sun/hotspot/WhiteBox.java	Wed Nov 05 08:22:17 2014 -0800
@@ -104,10 +104,10 @@
   public native void NMTCommitMemory(long addr, long size);
   public native void NMTUncommitMemory(long addr, long size);
   public native void NMTReleaseMemory(long addr, long size);
-  public native void NMTOverflowHashBucket(long num);
   public native long NMTMallocWithPseudoStack(long size, int index);
   public native boolean NMTIsDetailSupported();
   public native boolean NMTChangeTrackingLevel();
+  public native int NMTGetHashSize();
 
   // Compiler
   public native void    deoptimizeAll();