test/gc/TestSmallHeap.java

rev 7621 : [mq]: smalltest

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2015, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -24,36 +24,48 @@
 /**
  * @test TestSmallHeap
  * @bug 8067438
  * @requires vm.gc=="null"
  * @summary Verify that starting the VM with a small heap works
- * @library /testlibrary
- * @run main/othervm -Xmx4m -XX:+UseParallelGC TestSmallHeap
- * @run main/othervm -Xmx4m -XX:+UseSerialGC TestSmallHeap
- * @run main/othervm -Xmx4m -XX:+UseG1GC TestSmallHeap
- * @run main/othervm -Xmx4m -XX:+UseConcMarkSweepGC -XX:CMSMarkStackSizeMax=1032 TestSmallHeap
- *
- * Note: It would be nice to verify the minimal supported heap size here,
- * but that turns out to be quite tricky since we align the heap size based
- * on the card table size. And the card table size is aligned based on the
- * minimal pages size provided by the os. This means that on most platforms,
- * where the minimal page size is 4k, we get a minimal heap size of 2m but
- * on Solaris/Sparc we have a page size of 8k and get a minimal heap size
- * of 8m.
+ * @library /testlibrary /../../test/lib
+ * @build TestSmallHeap
+ * @run main ClassFileInstaller sun.hotspot.WhiteBox
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xmx2m -XX:+UseParallelGC TestSmallHeap
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xmx2m -XX:+UseSerialGC TestSmallHeap
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xmx2m -XX:+UseG1GC TestSmallHeap
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xmx2m -XX:+UseConcMarkSweepGC TestSmallHeap
+ *
+ * Note: It would be nice to verify the minimal supported heap size (2m) here,
+ * but we align the heap size based on the card table size. And the card table
+ * size is aligned based on the minimal pages size provided by the os. This
+ * means that on most platforms, where the minimal page size is 4k, we get a
+ * minimal heap size of 2m but on Solaris/Sparc we have a page size of 8k and
+ * get a minimal heap size of 4m. And on platforms where the page size is 64k
+ * we get a minimal heap size of 32m. We never use large pages for the card table.
+ *
  * There is also no check in the VM for verifying that the maximum heap size
  * is larger than the supported minimal heap size. This means that specifying
- * -Xmx1m on the command line is fine but will give a heap of 2m (or 4m).
- * To work around these rather strange behaviors this test uses 4m for all
- * platforms.
+ * -Xmx1m on the command line is fine but will give a heap of 2m (or 4m or 32m).
+ * 
+ * To work around these rather strange behaviors this test uses -Xmx2m but then
+ * calculates what the expected heap size should be. The calculation is a
+ * simplified version of the code in the VM. We assume that the card table will
+ * use one page. Each byte in the card table corresponds to 512 bytes on the heap.
+ * So, the expected heap size is page_size * 512.
  */
 
-import sun.management.ManagementFactoryHelper;
+import com.oracle.java.testlibrary.*;
 import static com.oracle.java.testlibrary.Asserts.*;
+import sun.hotspot.WhiteBox;
+import sun.management.ManagementFactoryHelper;
 
 public class TestSmallHeap {
 
     public static void main(String[] args) {
+        WhiteBox wb = WhiteBox.getWhiteBox();
+        int pageSize = wb.getVMPageSize();
+        int heapBytesPerCard = 512;
+        long expectedMaxHeap = pageSize * heapBytesPerCard;
         String maxHeap = ManagementFactoryHelper.getDiagnosticMXBean().getVMOption("MaxHeapSize").getValue();
-        String expectedMaxHeap = "4194304";
-        assertEQ(maxHeap, expectedMaxHeap);
+        assertEQ(Long.parseLong(maxHeap), expectedMaxHeap);
     }
 }