8013032: CMS: assert(used() == used_after_gc && used_after_gc <= capacity())...

8013032: CMS: assert(used() == used_after_gc && used_after_gc <= capacity()) failed: used: 0 used_after_gc: 292080 capacity: 1431699456
Reviewed-by: tschatzl, mgerdin, johnc

src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp

@@ -917,18 +917,14 @@ void ConcurrentMarkSweepGeneration::compute_new_size() {
     return;
   }
 
-  // Compute some numbers about the state of the heap.
-  const size_t used_after_gc = used();
-  const size_t capacity_after_gc = capacity();
+  // The heap has been compacted but not reset yet.
+  // Any metric such as free() or used() will be incorrect.
 
   CardGeneration::compute_new_size();
 
   // Reset again after a possible resizing
   cmsSpace()->reset_after_compaction();
 
-  assert(used() == used_after_gc && used_after_gc <= capacity(),
-         err_msg("used: " SIZE_FORMAT " used_after_gc: " SIZE_FORMAT
-         " capacity: " SIZE_FORMAT, used(), used_after_gc, capacity()));
 }
 
 void ConcurrentMarkSweepGeneration::compute_new_size_free_list() {

test/gc/concurrentMarkSweep/CheckAllocateAndSystemGC.java

+/*
+ * Copyright (c) 2013, 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test CheckAllocateAndSystemGC
+ * @summary CMS: assert(used() == used_after_gc && used_after_gc <= capacity()) failed: used: 0 used_after_gc: 292080 capacity: 1431699456
+ * @bug 8013032
+ * @key gc
+ * @key regression
+ * @library /testlibrary
+ * @run main/othervm CheckAllocateAndSystemGC
+ * @author jon.masamitsu@oracle.com
+ */
+
+import com.oracle.java.testlibrary.*;
+
+public class CheckAllocateAndSystemGC {
+  public static void main(String args[]) throws Exception {
+
+    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
+      "-showversion",
+      "-XX:+UseConcMarkSweepGC",
+      "-Xmn4m",
+      "-XX:MaxTenuringThreshold=1",
+      "-XX:-UseCMSCompactAtFullCollection",
+      "CheckAllocateAndSystemGC$AllocateAndSystemGC"
+      );
+
+    OutputAnalyzer output = new OutputAnalyzer(pb.start());
+
+    output.shouldNotContain("error");
+
+    output.shouldHaveExitValue(0);
+  }
+  static class AllocateAndSystemGC {
+    public static void main(String [] args) {
+      Integer x[] = new Integer [1000];
+      // Allocate enough objects to cause a minor collection.
+      // These allocations suffice for a 4m young geneneration.
+      for (int i = 0; i < 100; i++) {
+        Integer y[] = new Integer[10000];
+      }
+      System.gc();
+    }
+  }
+}