6916623: Align object to 16 bytes to use Compressed Oops with java heap up to 64Gb

Added new product ObjectAlignmentInBytes flag to control object alignment.

Reviewed-by: twisti, ysr, iveresov

hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp

@@ -32,6 +32,23 @@
 // highest ranked  free list lock rank
 int CompactibleFreeListSpace::_lockRank = Mutex::leaf + 3;
 
+// Defaults are 0 so things will break badly if incorrectly initialized.
+int CompactibleFreeListSpace::IndexSetStart  = 0;
+int CompactibleFreeListSpace::IndexSetStride = 0;
+
+size_t MinChunkSize = 0;
+
+void CompactibleFreeListSpace::set_cms_values() {
+  // Set CMS global values
+  assert(MinChunkSize == 0, "already set");
+  #define numQuanta(x,y) ((x+y-1)/y)
+  MinChunkSize = numQuanta(sizeof(FreeChunk), MinObjAlignmentInBytes) * MinObjAlignment;
+
+  assert(IndexSetStart == 0 && IndexSetStride == 0, "already set");
+  IndexSetStart  = MinObjAlignment;
+  IndexSetStride = MinObjAlignment;
+}
+
 // Constructor
 CompactibleFreeListSpace::CompactibleFreeListSpace(BlockOffsetSharedArray* bs,
   MemRegion mr, bool use_adaptive_freelists,
@@ -302,7 +319,7 @@ size_t CompactibleFreeListSpace::sumIndexedFreeListArrayReturnedBytes() {
 
 size_t CompactibleFreeListSpace::totalCountInIndexedFreeLists() const {
   size_t count = 0;
-  for (int i = MinChunkSize; i < IndexSetSize; i++) {
+  for (int i = (int)MinChunkSize; i < IndexSetSize; i++) {
     debug_only(
       ssize_t total_list_count = 0;
       for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL;

hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp

@@ -91,10 +91,10 @@ class CompactibleFreeListSpace: public CompactibleSpace {
   enum SomeConstants {
     SmallForLinearAlloc = 16,        // size < this then use _sLAB
     SmallForDictionary  = 257,       // size < this then use _indexedFreeList
-    IndexSetSize        = SmallForDictionary,  // keep this odd-sized
-    IndexSetStart       = MinObjAlignment,
-    IndexSetStride      = MinObjAlignment
+    IndexSetSize        = SmallForDictionary  // keep this odd-sized
   };
+  static int IndexSetStart;
+  static int IndexSetStride;
 
  private:
   enum FitStrategyOptions {
@@ -278,6 +278,9 @@ class CompactibleFreeListSpace: public CompactibleSpace {
   HeapWord* nearLargestChunk() const { return _nearLargestChunk; }
   void set_nearLargestChunk(HeapWord* v) { _nearLargestChunk = v; }
 
+  // Set CMS global values
+  static void set_cms_values();
+
   // Return the free chunk at the end of the space.  If no such
   // chunk exists, return NULL.
   FreeChunk* find_chunk_at_end();

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

@@ -159,7 +159,7 @@ ConcurrentMarkSweepGeneration::ConcurrentMarkSweepGeneration(
      CardTableRS* ct, bool use_adaptive_freelists,
      FreeBlockDictionary::DictionaryChoice dictionaryChoice) :
   CardGeneration(rs, initial_byte_size, level, ct),
-  _dilatation_factor(((double)MinChunkSize)/((double)(oopDesc::header_size()))),
+  _dilatation_factor(((double)MinChunkSize)/((double)(CollectedHeap::min_fill_size()))),
   _debug_collection_type(Concurrent_collection_type)
 {
   HeapWord* bottom = (HeapWord*) _virtual_space.low();
@@ -222,7 +222,7 @@ ConcurrentMarkSweepGeneration::ConcurrentMarkSweepGeneration(
   // promoting generation, we'll instead just use the mimimum
   // object size (which today is a header's worth of space);
   // note that all arithmetic is in units of HeapWords.
-  assert(MinChunkSize >= oopDesc::header_size(), "just checking");
+  assert(MinChunkSize >= CollectedHeap::min_fill_size(), "just checking");
   assert(_dilatation_factor >= 1.0, "from previous assert");
 }
 

hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/freeChunk.hpp

@@ -133,9 +133,5 @@ class FreeChunk VALUE_OBJ_CLASS_SPEC {
   void print_on(outputStream* st);
 };
 
-// Alignment helpers etc.
-#define numQuanta(x,y) ((x+y-1)/y)
-enum AlignmentConstants {
-  MinChunkSize = numQuanta(sizeof(FreeChunk), MinObjAlignmentInBytes) * MinObjAlignment
-};
+extern size_t MinChunkSize;