8057710: Refactor G1 heap region default sizes

Summary: Refactored the defines to instead be static const in a HeapRegionBounds class.
Reviewed-by: mgerdin, tschatzl

src/share/vm/gc_implementation/g1/heapRegion.cpp

@@ -28,6 +28,7 @@
 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
 #include "gc_implementation/g1/heapRegion.inline.hpp"
+#include "gc_implementation/g1/heapRegionBounds.inline.hpp"
 #include "gc_implementation/g1/heapRegionRemSet.hpp"
 #include "gc_implementation/g1/heapRegionManager.inline.hpp"
 #include "gc_implementation/shared/liveRange.hpp"
@@ -137,32 +138,16 @@ void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
   }
 }
 
-// Minimum region size; we won't go lower than that.
-// We might want to decrease this in the future, to deal with small
-// heaps a bit more efficiently.
-#define MIN_REGION_SIZE  (      1024 * 1024 )
-
-// Maximum region size; we don't go higher than that. There's a good
-// reason for having an upper bound. We don't want regions to get too
-// large, otherwise cleanup's effectiveness would decrease as there
-// will be fewer opportunities to find totally empty regions after
-// marking.
-#define MAX_REGION_SIZE  ( 32 * 1024 * 1024 )
-
-// The automatic region size calculation will try to have around this
-// many regions in the heap (based on the min heap size).
-#define TARGET_REGION_NUMBER          2048
-
 size_t HeapRegion::max_region_size() {
-  return (size_t)MAX_REGION_SIZE;
+  return HeapRegionBounds::max_size();
 }
 
 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
   uintx region_size = G1HeapRegionSize;
   if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
     size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
-    region_size = MAX2(average_heap_size / TARGET_REGION_NUMBER,
-                       (uintx) MIN_REGION_SIZE);
+    region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
+                       (uintx) HeapRegionBounds::min_size());
   }
 
   int region_size_log = log2_long((jlong) region_size);
@@ -172,10 +157,10 @@ void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_hea
   region_size = ((uintx)1 << region_size_log);
 
   // Now make sure that we don't go over or under our limits.
-  if (region_size < MIN_REGION_SIZE) {
-    region_size = MIN_REGION_SIZE;
-  } else if (region_size > MAX_REGION_SIZE) {
-    region_size = MAX_REGION_SIZE;
+  if (region_size < HeapRegionBounds::min_size()) {
+    region_size = HeapRegionBounds::min_size();
+  } else if (region_size > HeapRegionBounds::max_size()) {
+    region_size = HeapRegionBounds::max_size();
   }
 
   // And recalculate the log.

src/share/vm/gc_implementation/g1/heapRegionBounds.hpp

+/*
+ * Copyright (c) 2014, 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.
+ *
+ */
+
+#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONBOUNDS_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONBOUNDS_HPP
+
+class HeapRegionBounds : public AllStatic {
+private:
+  // Minimum region size; we won't go lower than that.
+  // We might want to decrease this in the future, to deal with small
+  // heaps a bit more efficiently.
+  static const size_t MIN_REGION_SIZE = 1024 * 1024;
+
+  // Maximum region size; we don't go higher than that. There's a good
+  // reason for having an upper bound. We don't want regions to get too
+  // large, otherwise cleanup's effectiveness would decrease as there
+  // will be fewer opportunities to find totally empty regions after
+  // marking.
+  static const size_t MAX_REGION_SIZE = 32 * 1024 * 1024;
+
+  // The automatic region size calculation will try to have around this
+  // many regions in the heap (based on the min heap size).
+  static const size_t TARGET_REGION_NUMBER = 2048;
+
+public:
+  static inline size_t min_size();
+  static inline size_t max_size();
+  static inline size_t target_number();
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONBOUNDS_HPP

src/share/vm/gc_implementation/g1/heapRegionBounds.inline.hpp

+/*
+ * Copyright (c) 2014, 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.
+ *
+ */
+
+#include "gc_implementation/g1/heapRegionBounds.hpp"
+
+size_t HeapRegionBounds::min_size() {
+  return MIN_REGION_SIZE;
+}
+
+size_t HeapRegionBounds::max_size() {
+  return MAX_REGION_SIZE;
+}
+
+size_t HeapRegionBounds::target_number() {
+  return TARGET_REGION_NUMBER;
+}