changeset 3995:4a916f2ce331

8003985: Support @Contended Annotation - JEP 142 Summary: HotSpot changes to support @Contended annotation. Reviewed-by: coleenp, kvn, jrose Contributed-by: Aleksey Shipilev <aleksey.shipilev@oracle.com>
author jwilhelm
date Mon, 14 Jan 2013 15:17:47 +0100
parents 90a92d5bca17
children 5b6a231e5a86 edd23b35b1a5
files agent/src/share/classes/sun/jvm/hotspot/oops/InstanceKlass.java src/cpu/sparc/vm/vm_version_sparc.cpp src/cpu/x86/vm/vm_version_x86.cpp src/share/vm/classfile/classFileParser.cpp src/share/vm/classfile/classFileParser.hpp src/share/vm/classfile/vmSymbols.hpp src/share/vm/oops/fieldInfo.hpp src/share/vm/oops/fieldStreams.hpp src/share/vm/oops/instanceKlass.hpp src/share/vm/runtime/globals.hpp src/share/vm/runtime/vmStructs.cpp
diffstat 11 files changed, 622 insertions(+), 97 deletions(-) [+]
line wrap: on
line diff
--- a/agent/src/share/classes/sun/jvm/hotspot/oops/InstanceKlass.java	Fri Jan 11 09:53:24 2013 -0800
+++ b/agent/src/share/classes/sun/jvm/hotspot/oops/InstanceKlass.java	Mon Jan 14 15:17:47 2013 +0100
@@ -52,6 +52,8 @@
   private static int LOW_OFFSET;
   private static int HIGH_OFFSET;
   private static int FIELD_SLOTS;
+  private static short FIELDINFO_TAG_SIZE;
+  private static short FIELDINFO_TAG_OFFSET;
 
   // ClassState constants
   private static int CLASS_STATE_ALLOCATED;
@@ -96,9 +98,12 @@
     NAME_INDEX_OFFSET              = db.lookupIntConstant("FieldInfo::name_index_offset").intValue();
     SIGNATURE_INDEX_OFFSET         = db.lookupIntConstant("FieldInfo::signature_index_offset").intValue();
     INITVAL_INDEX_OFFSET           = db.lookupIntConstant("FieldInfo::initval_index_offset").intValue();
-    LOW_OFFSET                     = db.lookupIntConstant("FieldInfo::low_offset").intValue();
-    HIGH_OFFSET                    = db.lookupIntConstant("FieldInfo::high_offset").intValue();
+    LOW_OFFSET                     = db.lookupIntConstant("FieldInfo::low_packed_offset").intValue();
+    HIGH_OFFSET                    = db.lookupIntConstant("FieldInfo::high_packed_offset").intValue();
     FIELD_SLOTS                    = db.lookupIntConstant("FieldInfo::field_slots").intValue();
+    FIELDINFO_TAG_SIZE             = db.lookupIntConstant("FIELDINFO_TAG_SIZE").shortValue();
+    FIELDINFO_TAG_OFFSET           = db.lookupIntConstant("FIELDINFO_TAG_OFFSET").shortValue();
+
     // read ClassState constants
     CLASS_STATE_ALLOCATED = db.lookupIntConstant("InstanceKlass::allocated").intValue();
     CLASS_STATE_LOADED = db.lookupIntConstant("InstanceKlass::loaded").intValue();
@@ -314,8 +319,12 @@
 
   public int getFieldOffset(int index) {
     U2Array fields = getFields();
-    return VM.getVM().buildIntFromShorts(fields.at(index * FIELD_SLOTS + LOW_OFFSET),
-                                         fields.at(index * FIELD_SLOTS + HIGH_OFFSET));
+    short lo = fields.at(index * FIELD_SLOTS + LOW_OFFSET);
+    short hi = fields.at(index * FIELD_SLOTS + HIGH_OFFSET);
+    if ((lo & FIELDINFO_TAG_SIZE) == FIELDINFO_TAG_OFFSET) {
+      return VM.getVM().buildIntFromShorts(lo, hi) >> FIELDINFO_TAG_SIZE;
+    }
+    throw new RuntimeException("should not reach here");
   }
 
   // Accessors for declared fields
--- a/src/cpu/sparc/vm/vm_version_sparc.cpp	Fri Jan 11 09:53:24 2013 -0800
+++ b/src/cpu/sparc/vm/vm_version_sparc.cpp	Mon Jan 14 15:17:47 2013 +0100
@@ -259,6 +259,10 @@
   if (!has_vis1()) // Drop to 0 if no VIS1 support
     UseVIS = 0;
 
+  if (FLAG_IS_DEFAULT(ContendedPaddingWidth) &&
+    (cache_line_size > ContendedPaddingWidth))
+    ContendedPaddingWidth = cache_line_size;
+
 #ifndef PRODUCT
   if (PrintMiscellaneous && Verbose) {
     tty->print("Allocation");
@@ -286,6 +290,9 @@
     if (PrefetchFieldsAhead > 0) {
       tty->print_cr("PrefetchFieldsAhead %d", PrefetchFieldsAhead);
     }
+    if (ContendedPaddingWidth > 0) {
+      tty->print_cr("ContendedPaddingWidth %d", ContendedPaddingWidth);
+    }
   }
 #endif // PRODUCT
 }
--- a/src/cpu/x86/vm/vm_version_x86.cpp	Fri Jan 11 09:53:24 2013 -0800
+++ b/src/cpu/x86/vm/vm_version_x86.cpp	Mon Jan 14 15:17:47 2013 +0100
@@ -734,6 +734,10 @@
   PrefetchFieldsAhead         = prefetch_fields_ahead();
 #endif
 
+  if (FLAG_IS_DEFAULT(ContendedPaddingWidth) &&
+     (cache_line_size > ContendedPaddingWidth))
+     ContendedPaddingWidth = cache_line_size;
+
 #ifndef PRODUCT
   if (PrintMiscellaneous && Verbose) {
     tty->print_cr("Logical CPUs per core: %u",
@@ -780,6 +784,9 @@
     if (PrefetchFieldsAhead > 0) {
       tty->print_cr("PrefetchFieldsAhead %d", PrefetchFieldsAhead);
     }
+    if (ContendedPaddingWidth > 0) {
+      tty->print_cr("ContendedPaddingWidth %d", ContendedPaddingWidth);
+    }
   }
 #endif // !PRODUCT
 }
--- a/src/share/vm/classfile/classFileParser.cpp	Fri Jan 11 09:53:24 2013 -0800
+++ b/src/share/vm/classfile/classFileParser.cpp	Mon Jan 14 15:17:47 2013 +0100
@@ -970,6 +970,12 @@
         runtime_visible_annotations_length = attribute_length;
         runtime_visible_annotations = cfs->get_u1_buffer();
         assert(runtime_visible_annotations != NULL, "null visible annotations");
+        parse_annotations(loader_data,
+                          runtime_visible_annotations,
+                          runtime_visible_annotations_length,
+                          cp,
+                          parsed_annotations,
+                          CHECK);
         cfs->skip_u1(runtime_visible_annotations_length, CHECK);
       } else if (PreserveAllAnnotations && attribute_name == vmSymbols::tag_runtime_invisible_annotations()) {
         runtime_invisible_annotations_length = attribute_length;
@@ -1216,19 +1222,16 @@
     field->initialize(access_flags.as_short(),
                       name_index,
                       signature_index,
-                      constantvalue_index,
-                      0);
+                      constantvalue_index);
+    BasicType type = cp->basic_type_for_signature_at(signature_index);
+
+    // Remember how many oops we encountered and compute allocation type
+    FieldAllocationType atype = fac->update(is_static, type);
+    field->set_allocation_type(atype);
+
+    // After field is initialized with type, we can augment it with aux info
     if (parsed_annotations.has_any_annotations())
       parsed_annotations.apply_to(field);
-
-    BasicType type = cp->basic_type_for_signature_at(signature_index);
-
-    // Remember how many oops we encountered and compute allocation type
-    FieldAllocationType atype = fac->update(is_static, type);
-
-    // The correct offset is computed later (all oop fields will be located together)
-    // We temporarily store the allocation type in the offset field
-    field->set_offset(atype);
   }
 
   int index = length;
@@ -1259,17 +1262,13 @@
       field->initialize(JVM_ACC_FIELD_INTERNAL,
                         injected[n].name_index,
                         injected[n].signature_index,
-                        0,
                         0);
 
       BasicType type = FieldType::basic_type(injected[n].signature());
 
       // Remember how many oops we encountered and compute allocation type
       FieldAllocationType atype = fac->update(false, type);
-
-      // The correct offset is computed later (all oop fields will be located together)
-      // We temporarily store the allocation type in the offset field
-      field->set_offset(atype);
+      field->set_allocation_type(atype);
       index++;
     }
   }
@@ -1735,7 +1734,8 @@
 }
 
 // Sift through annotations, looking for those significant to the VM:
-void ClassFileParser::parse_annotations(u1* buffer, int limit,
+void ClassFileParser::parse_annotations(ClassLoaderData* loader_data,
+                                        u1* buffer, int limit,
                                         constantPoolHandle cp,
                                         ClassFileParser::AnnotationCollector* coll,
                                         TRAPS) {
@@ -1752,9 +1752,12 @@
       e_type_off = 7,   // utf8 such as 'Ljava/lang/annotation/RetentionPolicy;'
       e_con_off = 9,    // utf8 payload, such as 'SOURCE', 'CLASS', 'RUNTIME'
       e_size = 11,     // end of 'e' annotation
-    c_tag_val = 'c',
-      c_con_off = 7,    // utf8 payload, such as 'I' or 'Ljava/lang/String;'
+    c_tag_val = 'c',    // payload is type
+      c_con_off = 7,    // utf8 payload, such as 'I'
       c_size = 9,       // end of 'c' annotation
+    s_tag_val = 's',    // payload is String
+      s_con_off = 7,    // utf8 payload, such as 'Ljava/lang/String;'
+      s_size = 9,
     min_size = 6        // smallest possible size (zero members)
   };
   while ((--nann) >= 0 && (index-2 + min_size <= limit)) {
@@ -1773,57 +1776,65 @@
     }
 
     // Here is where parsing particular annotations will take place.
-    AnnotationCollector::ID id = coll->annotation_index(aname);
+    AnnotationCollector::ID id = coll->annotation_index(loader_data, aname);
     if (id == AnnotationCollector::_unknown)  continue;
     coll->set_annotation(id);
-    // If there are no values, just set the bit and move on:
-    if (count == 0)   continue;
-
-    // For the record, here is how annotation payloads can be collected.
-    // Suppose we want to capture @Retention.value.  Here is how:
-    //if (id == AnnotationCollector::_class_Retention) {
-    //  Symbol* payload = NULL;
-    //  if (count == 1
-    //      && e_size == (index0 - index)  // match size
-    //      && e_tag_val == *(abase + tag_off)
-    //      && (check_symbol_at(cp, Bytes::get_Java_u2(abase + e_type_off))
-    //          == vmSymbols::RetentionPolicy_signature())
-    //      && member == vmSymbols::value_name()) {
-    //    payload = check_symbol_at(cp, Bytes::get_Java_u2(abase + e_con_off));
-    //  }
-    //  check_property(payload != NULL,
-    //                 "Invalid @Retention annotation at offset %u in class file %s",
-    //                 index0, CHECK);
-    //  if (payload != NULL) {
-    //      payload->increment_refcount();
-    //      coll->_class_RetentionPolicy = payload;
-    //  }
-    //}
+
+    if (id == AnnotationCollector::_sun_misc_Contended) {
+      if (count == 1
+          && s_size == (index - index0)  // match size
+          && s_tag_val == *(abase + tag_off)
+          && member == vmSymbols::value_name()) {
+        u2 group_index = Bytes::get_Java_u2(abase + s_con_off);
+        coll->set_contended_group(group_index);
+      } else {
+        coll->set_contended_group(0); // default contended group
+      }
+      coll->set_contended(true);
+    } else {
+      coll->set_contended(false);
+    }
   }
 }
 
-ClassFileParser::AnnotationCollector::ID ClassFileParser::AnnotationCollector::annotation_index(Symbol* name) {
+ClassFileParser::AnnotationCollector::ID
+ClassFileParser::AnnotationCollector::annotation_index(ClassLoaderData* loader_data,
+                                                                Symbol* name) {
   vmSymbols::SID sid = vmSymbols::find_sid(name);
+  bool privileged = false;
+  if (loader_data->is_the_null_class_loader_data()) {
+    // Privileged code can use all annotations.  Other code silently drops some.
+    privileged = true;
+  }
   switch (sid) {
   case vmSymbols::VM_SYMBOL_ENUM_NAME(java_lang_invoke_ForceInline_signature):
     if (_location != _in_method)  break;  // only allow for methods
+    if (!privileged)              break;  // only allow in privileged code
     return _method_ForceInline;
   case vmSymbols::VM_SYMBOL_ENUM_NAME(java_lang_invoke_DontInline_signature):
     if (_location != _in_method)  break;  // only allow for methods
+    if (!privileged)              break;  // only allow in privileged code
     return _method_DontInline;
   case vmSymbols::VM_SYMBOL_ENUM_NAME(java_lang_invoke_LambdaForm_Compiled_signature):
     if (_location != _in_method)  break;  // only allow for methods
+    if (!privileged)              break;  // only allow in privileged code
     return _method_LambdaForm_Compiled;
   case vmSymbols::VM_SYMBOL_ENUM_NAME(java_lang_invoke_LambdaForm_Hidden_signature):
     if (_location != _in_method)  break;  // only allow for methods
+    if (!privileged)              break;  // only allow in privileged code
     return _method_LambdaForm_Hidden;
+  case vmSymbols::VM_SYMBOL_ENUM_NAME(sun_misc_Contended_signature):
+    if (_location != _in_field && _location != _in_class)          break;  // only allow for fields and classes
+    if (!EnableContended || (RestrictContended && !privileged))    break;  // honor privileges
+    return _sun_misc_Contended;
   default: break;
   }
   return AnnotationCollector::_unknown;
 }
 
 void ClassFileParser::FieldAnnotationCollector::apply_to(FieldInfo* f) {
-  fatal("no field annotations yet");
+  if (is_contended())
+    f->set_contended_group(contended_group());
 }
 
 void ClassFileParser::MethodAnnotationCollector::apply_to(methodHandle m) {
@@ -1838,7 +1849,7 @@
 }
 
 void ClassFileParser::ClassAnnotationCollector::apply_to(instanceKlassHandle k) {
-  fatal("no class annotations yet");
+  k->set_is_contended(is_contended());
 }
 
 
@@ -2181,7 +2192,8 @@
         runtime_visible_annotations_length = method_attribute_length;
         runtime_visible_annotations = cfs->get_u1_buffer();
         assert(runtime_visible_annotations != NULL, "null visible annotations");
-        parse_annotations(runtime_visible_annotations,
+        parse_annotations(loader_data,
+            runtime_visible_annotations,
             runtime_visible_annotations_length, cp, &parsed_annotations,
             CHECK_(nullHandle));
         cfs->skip_u1(runtime_visible_annotations_length, CHECK_(nullHandle));
@@ -2886,7 +2898,8 @@
         runtime_visible_annotations_length = attribute_length;
         runtime_visible_annotations = cfs->get_u1_buffer();
         assert(runtime_visible_annotations != NULL, "null visible annotations");
-        parse_annotations(runtime_visible_annotations,
+        parse_annotations(loader_data,
+                          runtime_visible_annotations,
                           runtime_visible_annotations_length,
                           cp,
                           parsed_annotations,
@@ -3405,18 +3418,21 @@
     // Size of Java itable (in words)
     itable_size = access_flags.is_interface() ? 0 : klassItable::compute_itable_size(transitive_interfaces);
 
+    // get the padding width from the option
+    // TODO: Ask VM about specific CPU we are running on
+    int pad_size = ContendedPaddingWidth;
+
     // Field size and offset computation
     int nonstatic_field_size = super_klass() == NULL ? 0 : super_klass->nonstatic_field_size();
 #ifndef PRODUCT
     int orig_nonstatic_field_size = 0;
 #endif
-    int static_field_size = 0;
     int next_static_oop_offset;
     int next_static_double_offset;
     int next_static_word_offset;
     int next_static_short_offset;
     int next_static_byte_offset;
-    int next_static_type_offset;
+    int next_static_padded_offset;
     int next_nonstatic_oop_offset;
     int next_nonstatic_double_offset;
     int next_nonstatic_word_offset;
@@ -3426,11 +3442,36 @@
     int first_nonstatic_oop_offset;
     int first_nonstatic_field_offset;
     int next_nonstatic_field_offset;
+    int next_nonstatic_padded_offset;
+
+    // Count the contended fields by type.
+    int static_contended_count = 0;
+    int nonstatic_contended_count = 0;
+    FieldAllocationCount fac_contended;
+    for (AllFieldStream fs(fields, cp); !fs.done(); fs.next()) {
+      FieldAllocationType atype = (FieldAllocationType) fs.allocation_type();
+      if (fs.is_contended()) {
+        fac_contended.count[atype]++;
+        if (fs.access_flags().is_static()) {
+          static_contended_count++;
+        } else {
+          nonstatic_contended_count++;
+        }
+      }
+    }
+    int contended_count = static_contended_count + nonstatic_contended_count;
+
 
     // Calculate the starting byte offsets
     next_static_oop_offset      = InstanceMirrorKlass::offset_of_static_fields();
+
+    // class is contended, pad before all the fields
+    if (parsed_annotations.is_contended()) {
+      next_static_oop_offset += pad_size;
+    }
+
     next_static_double_offset   = next_static_oop_offset +
-                                  (fac.count[STATIC_OOP] * heapOopSize);
+                                  ((fac.count[STATIC_OOP] - fac_contended.count[STATIC_OOP]) * heapOopSize);
     if ( fac.count[STATIC_DOUBLE] &&
          (Universe::field_type_should_be_aligned(T_DOUBLE) ||
           Universe::field_type_should_be_aligned(T_LONG)) ) {
@@ -3438,25 +3479,29 @@
     }
 
     next_static_word_offset     = next_static_double_offset +
-                                  (fac.count[STATIC_DOUBLE] * BytesPerLong);
+                                  ((fac.count[STATIC_DOUBLE] - fac_contended.count[STATIC_DOUBLE]) * BytesPerLong);
     next_static_short_offset    = next_static_word_offset +
-                                  (fac.count[STATIC_WORD] * BytesPerInt);
+                                  ((fac.count[STATIC_WORD]   - fac_contended.count[STATIC_WORD]) * BytesPerInt);
     next_static_byte_offset     = next_static_short_offset +
-                                  (fac.count[STATIC_SHORT] * BytesPerShort);
-    next_static_type_offset     = align_size_up((next_static_byte_offset +
-                                  fac.count[STATIC_BYTE] ), wordSize );
-    static_field_size           = (next_static_type_offset -
-                                  next_static_oop_offset) / wordSize;
+                                  ((fac.count[STATIC_SHORT]  - fac_contended.count[STATIC_SHORT]) * BytesPerShort);
+    next_static_padded_offset   = next_static_byte_offset +
+                                  ((fac.count[STATIC_BYTE]   - fac_contended.count[STATIC_BYTE]) * 1);
 
     first_nonstatic_field_offset = instanceOopDesc::base_offset_in_bytes() +
                                    nonstatic_field_size * heapOopSize;
+
+    // class is contended, pad before all the fields
+    if (parsed_annotations.is_contended()) {
+      first_nonstatic_field_offset += pad_size;
+    }
+
     next_nonstatic_field_offset = first_nonstatic_field_offset;
 
-    unsigned int nonstatic_double_count = fac.count[NONSTATIC_DOUBLE];
-    unsigned int nonstatic_word_count   = fac.count[NONSTATIC_WORD];
-    unsigned int nonstatic_short_count  = fac.count[NONSTATIC_SHORT];
-    unsigned int nonstatic_byte_count   = fac.count[NONSTATIC_BYTE];
-    unsigned int nonstatic_oop_count    = fac.count[NONSTATIC_OOP];
+    unsigned int nonstatic_double_count = fac.count[NONSTATIC_DOUBLE] - fac_contended.count[NONSTATIC_DOUBLE];
+    unsigned int nonstatic_word_count   = fac.count[NONSTATIC_WORD]   - fac_contended.count[NONSTATIC_WORD];
+    unsigned int nonstatic_short_count  = fac.count[NONSTATIC_SHORT]  - fac_contended.count[NONSTATIC_SHORT];
+    unsigned int nonstatic_byte_count   = fac.count[NONSTATIC_BYTE]   - fac_contended.count[NONSTATIC_BYTE];
+    unsigned int nonstatic_oop_count    = fac.count[NONSTATIC_OOP]    - fac_contended.count[NONSTATIC_OOP];
 
     bool super_has_nonstatic_fields =
             (super_klass() != NULL && super_klass->has_nonstatic_fields());
@@ -3529,12 +3574,12 @@
     }
 
     if( allocation_style == 0 ) {
-      // Fields order: oops, longs/doubles, ints, shorts/chars, bytes
+      // Fields order: oops, longs/doubles, ints, shorts/chars, bytes, padded fields
       next_nonstatic_oop_offset    = next_nonstatic_field_offset;
       next_nonstatic_double_offset = next_nonstatic_oop_offset +
                                       (nonstatic_oop_count * heapOopSize);
     } else if( allocation_style == 1 ) {
-      // Fields order: longs/doubles, ints, shorts/chars, bytes, oops
+      // Fields order: longs/doubles, ints, shorts/chars, bytes, oops, padded fields
       next_nonstatic_double_offset = next_nonstatic_field_offset;
     } else if( allocation_style == 2 ) {
       // Fields allocation: oops fields in super and sub classes are together.
@@ -3613,27 +3658,33 @@
                                   (nonstatic_word_count * BytesPerInt);
     next_nonstatic_byte_offset  = next_nonstatic_short_offset +
                                   (nonstatic_short_count * BytesPerShort);
-
-    int notaligned_offset;
-    if( allocation_style == 0 ) {
-      notaligned_offset = next_nonstatic_byte_offset + nonstatic_byte_count;
-    } else { // allocation_style == 1
-      next_nonstatic_oop_offset = next_nonstatic_byte_offset + nonstatic_byte_count;
+    next_nonstatic_padded_offset = next_nonstatic_byte_offset +
+                                  nonstatic_byte_count;
+
+    // let oops jump before padding with this allocation style
+    if( allocation_style == 1 ) {
+      next_nonstatic_oop_offset = next_nonstatic_padded_offset;
       if( nonstatic_oop_count > 0 ) {
         next_nonstatic_oop_offset = align_size_up(next_nonstatic_oop_offset, heapOopSize);
       }
-      notaligned_offset = next_nonstatic_oop_offset + (nonstatic_oop_count * heapOopSize);
+      next_nonstatic_padded_offset = next_nonstatic_oop_offset + (nonstatic_oop_count * heapOopSize);
     }
-    next_nonstatic_type_offset = align_size_up(notaligned_offset, heapOopSize );
-    nonstatic_field_size = nonstatic_field_size + ((next_nonstatic_type_offset
-                                   - first_nonstatic_field_offset)/heapOopSize);
 
     // Iterate over fields again and compute correct offsets.
     // The field allocation type was temporarily stored in the offset slot.
     // oop fields are located before non-oop fields (static and non-static).
     for (AllFieldStream fs(fields, cp); !fs.done(); fs.next()) {
+
+      // skip already laid out fields
+      if (fs.is_offset_set()) continue;
+
+      // contended fields are handled below
+      if (fs.is_contended()) continue;
+
       int real_offset;
-      FieldAllocationType atype = (FieldAllocationType) fs.offset();
+      FieldAllocationType atype = (FieldAllocationType) fs.allocation_type();
+
+      // pack the rest of the fields
       switch (atype) {
         case STATIC_OOP:
           real_offset = next_static_oop_offset;
@@ -3722,13 +3773,225 @@
       fs.set_offset(real_offset);
     }
 
+
+    // Handle the contended cases.
+    //
+    // Each contended field should not intersect the cache line with another contended field.
+    // In the absence of alignment information, we end up with pessimistically separating
+    // the fields with full-width padding.
+    //
+    // Additionally, this should not break alignment for the fields, so we round the alignment up
+    // for each field.
+    if (contended_count > 0) {
+
+      // if there is at least one contended field, we need to have pre-padding for them
+      if (nonstatic_contended_count > 0) {
+        next_nonstatic_padded_offset += pad_size;
+      }
+
+      // collect all contended groups
+      BitMap bm(cp->size());
+      for (AllFieldStream fs(fields, cp); !fs.done(); fs.next()) {
+        // skip already laid out fields
+        if (fs.is_offset_set()) continue;
+
+        if (fs.is_contended()) {
+          bm.set_bit(fs.contended_group());
+        }
+      }
+
+      int current_group = -1;
+      while ((current_group = (int)bm.get_next_one_offset(current_group + 1)) != (int)bm.size()) {
+
+        for (AllFieldStream fs(fields, cp); !fs.done(); fs.next()) {
+
+          // skip already laid out fields
+          if (fs.is_offset_set()) continue;
+
+          // skip non-contended fields and fields from different group
+          if (!fs.is_contended() || (fs.contended_group() != current_group)) continue;
+
+          // handle statics below
+          if (fs.access_flags().is_static()) continue;
+
+          int real_offset;
+          FieldAllocationType atype = (FieldAllocationType) fs.allocation_type();
+
+          switch (atype) {
+            case NONSTATIC_BYTE:
+              next_nonstatic_padded_offset = align_size_up(next_nonstatic_padded_offset, 1);
+              real_offset = next_nonstatic_padded_offset;
+              next_nonstatic_padded_offset += 1;
+              break;
+
+            case NONSTATIC_SHORT:
+              next_nonstatic_padded_offset = align_size_up(next_nonstatic_padded_offset, BytesPerShort);
+              real_offset = next_nonstatic_padded_offset;
+              next_nonstatic_padded_offset += BytesPerShort;
+              break;
+
+            case NONSTATIC_WORD:
+              next_nonstatic_padded_offset = align_size_up(next_nonstatic_padded_offset, BytesPerInt);
+              real_offset = next_nonstatic_padded_offset;
+              next_nonstatic_padded_offset += BytesPerInt;
+              break;
+
+            case NONSTATIC_DOUBLE:
+              next_nonstatic_padded_offset = align_size_up(next_nonstatic_padded_offset, BytesPerLong);
+              real_offset = next_nonstatic_padded_offset;
+              next_nonstatic_padded_offset += BytesPerLong;
+              break;
+
+            case NONSTATIC_OOP:
+              next_nonstatic_padded_offset = align_size_up(next_nonstatic_padded_offset, heapOopSize);
+              real_offset = next_nonstatic_padded_offset;
+              next_nonstatic_padded_offset += heapOopSize;
+
+              // Create new oop map
+              nonstatic_oop_offsets[nonstatic_oop_map_count] = real_offset;
+              nonstatic_oop_counts [nonstatic_oop_map_count] = 1;
+              nonstatic_oop_map_count += 1;
+              if( first_nonstatic_oop_offset == 0 ) { // Undefined
+                first_nonstatic_oop_offset = real_offset;
+              }
+              break;
+
+            default:
+              ShouldNotReachHere();
+          }
+
+          if (fs.contended_group() == 0) {
+            // Contended group defines the equivalence class over the fields:
+            // the fields within the same contended group are not inter-padded.
+            // The only exception is default group, which does not incur the
+            // equivalence, and so requires intra-padding.
+            next_nonstatic_padded_offset += pad_size;
+          }
+
+          fs.set_offset(real_offset);
+        } // for
+
+        // Start laying out the next group.
+        // Note that this will effectively pad the last group in the back;
+        // this is expected to alleviate memory contention effects for
+        // subclass fields and/or adjacent object.
+        // If this was the default group, the padding is already in place.
+        if (current_group != 0) {
+          next_nonstatic_padded_offset += pad_size;
+        }
+      }
+
+      // handle static fields
+
+      // if there is at least one contended field, we need to have pre-padding for them
+      if (static_contended_count > 0) {
+        next_static_padded_offset += pad_size;
+      }
+
+      current_group = -1;
+      while ((current_group = (int)bm.get_next_one_offset(current_group + 1)) != (int)bm.size()) {
+
+        for (AllFieldStream fs(fields, cp); !fs.done(); fs.next()) {
+
+          // skip already laid out fields
+          if (fs.is_offset_set()) continue;
+
+          // skip non-contended fields and fields from different group
+          if (!fs.is_contended() || (fs.contended_group() != current_group)) continue;
+
+          // non-statics already handled above
+          if (!fs.access_flags().is_static()) continue;
+
+          int real_offset;
+          FieldAllocationType atype = (FieldAllocationType) fs.allocation_type();
+
+          switch (atype) {
+
+            case STATIC_BYTE:
+              next_static_padded_offset = align_size_up(next_static_padded_offset, 1);
+              real_offset = next_static_padded_offset;
+              next_static_padded_offset += 1;
+              break;
+
+            case STATIC_SHORT:
+              next_static_padded_offset = align_size_up(next_static_padded_offset, BytesPerShort);
+              real_offset = next_static_padded_offset;
+              next_static_padded_offset += BytesPerShort;
+              break;
+
+            case STATIC_WORD:
+              next_static_padded_offset = align_size_up(next_static_padded_offset, BytesPerInt);
+              real_offset = next_static_padded_offset;
+              next_static_padded_offset += BytesPerInt;
+              break;
+
+            case STATIC_DOUBLE:
+              next_static_padded_offset = align_size_up(next_static_padded_offset, BytesPerLong);
+              real_offset = next_static_padded_offset;
+              next_static_padded_offset += BytesPerLong;
+              break;
+
+            case STATIC_OOP:
+              next_static_padded_offset = align_size_up(next_static_padded_offset, heapOopSize);
+              real_offset = next_static_padded_offset;
+              next_static_padded_offset += heapOopSize;
+              break;
+
+            default:
+              ShouldNotReachHere();
+          }
+
+          if (fs.contended_group() == 0) {
+            // Contended group defines the equivalence class over the fields:
+            // the fields within the same contended group are not inter-padded.
+            // The only exception is default group, which does not incur the
+            // equivalence, and so requires intra-padding.
+            next_static_padded_offset += pad_size;
+          }
+
+          fs.set_offset(real_offset);
+        } // for
+
+        // Start laying out the next group.
+        // Note that this will effectively pad the last group in the back;
+        // this is expected to alleviate memory contention effects for
+        // subclass fields and/or adjacent object.
+        // If this was the default group, the padding is already in place.
+        if (current_group != 0) {
+          next_static_padded_offset += pad_size;
+        }
+
+      }
+
+    } // handle contended
+
     // Size of instances
     int instance_size;
 
+    int notaligned_offset = next_nonstatic_padded_offset;
+
+    // Entire class is contended, pad in the back.
+    // This helps to alleviate memory contention effects for subclass fields
+    // and/or adjacent object.
+    if (parsed_annotations.is_contended()) {
+      notaligned_offset += pad_size;
+      next_static_padded_offset += pad_size;
+    }
+
+    int next_static_type_offset     = align_size_up(next_static_padded_offset, wordSize);
+    int static_field_size           = (next_static_type_offset -
+                                  InstanceMirrorKlass::offset_of_static_fields()) / wordSize;
+
+    next_nonstatic_type_offset = align_size_up(notaligned_offset, heapOopSize );
+    nonstatic_field_size = nonstatic_field_size + ((next_nonstatic_type_offset
+                                   - first_nonstatic_field_offset)/heapOopSize);
+
     next_nonstatic_type_offset = align_size_up(notaligned_offset, wordSize );
     instance_size = align_object_size(next_nonstatic_type_offset / wordSize);
 
-    assert(instance_size == align_object_size(align_size_up((instanceOopDesc::base_offset_in_bytes() + nonstatic_field_size*heapOopSize), wordSize) / wordSize), "consistent layout helper value");
+    assert(instance_size == align_object_size(align_size_up(
+                (instanceOopDesc::base_offset_in_bytes() + nonstatic_field_size*heapOopSize + ((parsed_annotations.is_contended()) ? pad_size : 0)),
+            wordSize) / wordSize), "consistent layout helper value");
 
     // Number of non-static oop map blocks allocated at end of klass.
     const unsigned int total_oop_map_count =
@@ -4008,6 +4271,18 @@
     }
 #endif
 
+#ifndef PRODUCT
+    if (PrintFieldLayout) {
+      print_field_layout(name,
+            fields,
+            cp,
+            instance_size,
+            first_nonstatic_field_offset,
+            next_nonstatic_field_offset,
+            next_static_type_offset);
+    }
+#endif
+
     // preserve result across HandleMark
     preserve_this_klass = this_klass();
   }
@@ -4020,6 +4295,38 @@
   return this_klass;
 }
 
+void ClassFileParser::print_field_layout(Symbol* name,
+                                         Array<u2>* fields,
+                                         constantPoolHandle cp,
+                                         int instance_size,
+                                         int instance_fields_start,
+                                         int instance_fields_end,
+                                         int static_fields_end) {
+  tty->print("%s: field layout\n", name->as_klass_external_name());
+  tty->print("  @%3d %s\n", instance_fields_start, "--- instance fields start ---");
+  for (AllFieldStream fs(fields, cp); !fs.done(); fs.next()) {
+    if (!fs.access_flags().is_static()) {
+      tty->print("  @%3d \"%s\" %s\n",
+          fs.offset(),
+          fs.name()->as_klass_external_name(),
+          fs.signature()->as_klass_external_name());
+    }
+  }
+  tty->print("  @%3d %s\n", instance_fields_end, "--- instance fields end ---");
+  tty->print("  @%3d %s\n", instance_size * wordSize, "--- instance ends ---");
+  tty->print("  @%3d %s\n", InstanceMirrorKlass::offset_of_static_fields(), "--- static fields start ---");
+  for (AllFieldStream fs(fields, cp); !fs.done(); fs.next()) {
+    if (fs.access_flags().is_static()) {
+      tty->print("  @%3d \"%s\" %s\n",
+          fs.offset(),
+          fs.name()->as_klass_external_name(),
+          fs.signature()->as_klass_external_name());
+    }
+  }
+  tty->print("  @%3d %s\n", static_fields_end, "--- static fields end ---");
+  tty->print("\n");
+}
+
 unsigned int
 ClassFileParser::compute_oop_map_count(instanceKlassHandle super,
                                        unsigned int nonstatic_oop_map_count,
--- a/src/share/vm/classfile/classFileParser.hpp	Fri Jan 11 09:53:24 2013 -0800
+++ b/src/share/vm/classfile/classFileParser.hpp	Mon Jan 14 15:17:47 2013 +0100
@@ -95,17 +95,20 @@
       _method_DontInline,
       _method_LambdaForm_Compiled,
       _method_LambdaForm_Hidden,
+      _sun_misc_Contended,
       _annotation_LIMIT
     };
     const Location _location;
     int _annotations_present;
+    u2 _contended_group;
+
     AnnotationCollector(Location location)
     : _location(location), _annotations_present(0)
     {
       assert((int)_annotation_LIMIT <= (int)sizeof(_annotations_present) * BitsPerByte, "");
     }
     // If this annotation name has an ID, report it (or _none).
-    ID annotation_index(Symbol* name);
+    ID annotation_index(ClassLoaderData* loader_data, Symbol* name);
     // Set the annotation name:
     void set_annotation(ID id) {
       assert((int)id >= 0 && (int)id < (int)_annotation_LIMIT, "oob");
@@ -114,6 +117,12 @@
     // Report if the annotation is present.
     bool has_any_annotations() { return _annotations_present != 0; }
     bool has_annotation(ID id) { return (nth_bit((int)id) & _annotations_present) != 0; }
+
+    void set_contended_group(u2 group) { _contended_group = group; }
+    u2 contended_group() { return _contended_group; }
+
+    void set_contended(bool contended) { set_annotation(_sun_misc_Contended); }
+    bool is_contended() { return has_annotation(_sun_misc_Contended); }
   };
   class FieldAnnotationCollector: public AnnotationCollector {
   public:
@@ -177,6 +186,14 @@
                           Array<AnnotationArray*>** fields_type_annotations,
                           u2* java_fields_count_ptr, TRAPS);
 
+  void print_field_layout(Symbol* name,
+                          Array<u2>* fields,
+                          constantPoolHandle cp,
+                          int instance_size,
+                          int instance_fields_start,
+                          int instance_fields_end,
+                          int static_fields_end);
+
   // Method parsing
   methodHandle parse_method(ClassLoaderData* loader_data,
                             constantPoolHandle cp,
@@ -247,7 +264,8 @@
                                         int runtime_invisible_annotations_length, TRAPS);
   int skip_annotation(u1* buffer, int limit, int index);
   int skip_annotation_value(u1* buffer, int limit, int index);
-  void parse_annotations(u1* buffer, int limit, constantPoolHandle cp,
+  void parse_annotations(ClassLoaderData* loader_data,
+                         u1* buffer, int limit, constantPoolHandle cp,
                          /* Results (currently, only one result is supported): */
                          AnnotationCollector* result,
                          TRAPS);
--- a/src/share/vm/classfile/vmSymbols.hpp	Fri Jan 11 09:53:24 2013 -0800
+++ b/src/share/vm/classfile/vmSymbols.hpp	Mon Jan 14 15:17:47 2013 +0100
@@ -194,7 +194,10 @@
   template(java_lang_VirtualMachineError,             "java/lang/VirtualMachineError")            \
   template(java_lang_StackOverflowError,              "java/lang/StackOverflowError")             \
   template(java_lang_StackTraceElement,               "java/lang/StackTraceElement")              \
+                                                                                                  \
+  /* Concurrency support */                                                                       \
   template(java_util_concurrent_locks_AbstractOwnableSynchronizer,   "java/util/concurrent/locks/AbstractOwnableSynchronizer") \
+  template(sun_misc_Contended_signature,              "Lsun/misc/Contended;")                     \
                                                                                                   \
   /* class symbols needed by intrinsics */                                                        \
   VM_INTRINSICS_DO(VM_INTRINSIC_IGNORE, template, VM_SYMBOL_IGNORE, VM_SYMBOL_IGNORE, VM_ALIAS_IGNORE) \
@@ -284,7 +287,7 @@
   NOT_LP64(  do_alias(intptr_signature,               int_signature)  )                           \
   LP64_ONLY( do_alias(intptr_signature,               long_signature) )                           \
   template(selectAlternative_signature, "(ZLjava/lang/invoke/MethodHandle;Ljava/lang/invoke/MethodHandle;)Ljava/lang/invoke/MethodHandle;") \
-                                                                                                  \
+                                                                      \
   /* common method and field names */                                                             \
   template(object_initializer_name,                   "<init>")                                   \
   template(class_initializer_name,                    "<clinit>")                                 \
--- a/src/share/vm/oops/fieldInfo.hpp	Fri Jan 11 09:53:24 2013 -0800
+++ b/src/share/vm/oops/fieldInfo.hpp	Mon Jan 14 15:17:47 2013 +0100
@@ -43,14 +43,29 @@
  public:
   // fields
   // Field info extracted from the class file and stored
-  // as an array of 7 shorts
+  // as an array of 6 shorts.
+
+#define FIELDINFO_TAG_SIZE             2
+#define FIELDINFO_TAG_BLANK            0
+#define FIELDINFO_TAG_OFFSET           1
+#define FIELDINFO_TAG_TYPE_PLAIN       2
+#define FIELDINFO_TAG_TYPE_CONTENDED   3
+#define FIELDINFO_TAG_MASK             3
+
+  // Packed field has the tag, and can be either of:
+  //    hi bits <--------------------------- lo bits
+  //   |---------high---------|---------low---------|
+  //    ..........................................00  - blank
+  //    [------------------offset----------------]01  - real field offset
+  //    ......................[-------type-------]10  - plain field with type
+  //    [--contention_group--][-------type-------]11  - contended field with type and contention group
   enum FieldOffset {
     access_flags_offset      = 0,
     name_index_offset        = 1,
     signature_index_offset   = 2,
     initval_index_offset     = 3,
-    low_offset               = 4,
-    high_offset              = 5,
+    low_packed_offset        = 4,
+    high_packed_offset       = 5,
     field_slots              = 6
   };
 
@@ -76,17 +91,90 @@
   void initialize(u2 access_flags,
                   u2 name_index,
                   u2 signature_index,
-                  u2 initval_index,
-                  u4 offset) {
+                  u2 initval_index) {
     _shorts[access_flags_offset] = access_flags;
     _shorts[name_index_offset] = name_index;
     _shorts[signature_index_offset] = signature_index;
     _shorts[initval_index_offset] = initval_index;
-    set_offset(offset);
+    _shorts[low_packed_offset] = 0;
+    _shorts[high_packed_offset] = 0;
   }
 
   u2 access_flags() const                        { return _shorts[access_flags_offset];            }
-  u4 offset() const                              { return build_int_from_shorts(_shorts[low_offset], _shorts[high_offset]); }
+  u4 offset() const {
+    u2 lo = _shorts[low_packed_offset];
+    switch(lo & FIELDINFO_TAG_MASK) {
+      case FIELDINFO_TAG_OFFSET:
+        return build_int_from_shorts(_shorts[low_packed_offset], _shorts[high_packed_offset]) >> FIELDINFO_TAG_SIZE;
+#ifndef PRODUCT
+      case FIELDINFO_TAG_TYPE_PLAIN:
+        ShouldNotReachHere2("Asking offset for the plain type field");
+      case FIELDINFO_TAG_TYPE_CONTENDED:
+        ShouldNotReachHere2("Asking offset for the contended type field");
+      case FIELDINFO_TAG_BLANK:
+        ShouldNotReachHere2("Asking offset for the blank field");
+#endif
+    }
+    ShouldNotReachHere();
+    return 0;
+  }
+
+  bool is_contended() const {
+    u2 lo = _shorts[low_packed_offset];
+    switch(lo & FIELDINFO_TAG_MASK) {
+      case FIELDINFO_TAG_TYPE_PLAIN:
+        return false;
+      case FIELDINFO_TAG_TYPE_CONTENDED:
+        return true;
+#ifndef PRODUCT
+      case FIELDINFO_TAG_OFFSET:
+        ShouldNotReachHere2("Asking contended flag for the field with offset");
+      case FIELDINFO_TAG_BLANK:
+        ShouldNotReachHere2("Asking contended flag for the blank field");
+#endif
+    }
+    ShouldNotReachHere();
+    return false;
+  }
+
+  u2 contended_group() const {
+    u2 lo = _shorts[low_packed_offset];
+    switch(lo & FIELDINFO_TAG_MASK) {
+      case FIELDINFO_TAG_TYPE_PLAIN:
+        return 0;
+      case FIELDINFO_TAG_TYPE_CONTENDED:
+        return _shorts[high_packed_offset];
+#ifndef PRODUCT
+      case FIELDINFO_TAG_OFFSET:
+        ShouldNotReachHere2("Asking the contended group for the field with offset");
+      case FIELDINFO_TAG_BLANK:
+        ShouldNotReachHere2("Asking the contended group for the blank field");
+#endif
+    }
+    ShouldNotReachHere();
+    return 0;
+ }
+
+  u2 allocation_type() const {
+    u2 lo = _shorts[low_packed_offset];
+    switch(lo & FIELDINFO_TAG_MASK) {
+      case FIELDINFO_TAG_TYPE_PLAIN:
+      case FIELDINFO_TAG_TYPE_CONTENDED:
+        return (lo >> FIELDINFO_TAG_SIZE);
+#ifndef PRODUCT
+      case FIELDINFO_TAG_OFFSET:
+        ShouldNotReachHere2("Asking the field type for field with offset");
+      case FIELDINFO_TAG_BLANK:
+        ShouldNotReachHere2("Asking the field type for the blank field");
+#endif
+    }
+    ShouldNotReachHere();
+    return 0;
+  }
+
+  bool is_offset_set() const {
+    return (_shorts[low_packed_offset] & FIELDINFO_TAG_MASK) == FIELDINFO_TAG_OFFSET;
+  }
 
   Symbol* name(constantPoolHandle cp) const {
     int index = name_index();
@@ -106,8 +194,46 @@
 
   void set_access_flags(u2 val)                  { _shorts[access_flags_offset] = val;             }
   void set_offset(u4 val)                        {
-    _shorts[low_offset] = extract_low_short_from_int(val);
-    _shorts[high_offset] = extract_high_short_from_int(val);
+    val = val << FIELDINFO_TAG_SIZE; // make room for tag
+    _shorts[low_packed_offset] = extract_low_short_from_int(val) | FIELDINFO_TAG_OFFSET;
+    _shorts[high_packed_offset] = extract_high_short_from_int(val);
+  }
+
+  void set_allocation_type(int type) {
+    u2 lo = _shorts[low_packed_offset];
+    switch(lo & FIELDINFO_TAG_MASK) {
+      case FIELDINFO_TAG_BLANK:
+        _shorts[low_packed_offset] = ((type << FIELDINFO_TAG_SIZE)) & 0xFFFF;
+        _shorts[low_packed_offset] &= ~FIELDINFO_TAG_MASK;
+        _shorts[low_packed_offset] |= FIELDINFO_TAG_TYPE_PLAIN;
+        return;
+#ifndef PRODUCT
+      case FIELDINFO_TAG_TYPE_PLAIN:
+      case FIELDINFO_TAG_TYPE_CONTENDED:
+      case FIELDINFO_TAG_OFFSET:
+        ShouldNotReachHere2("Setting the field type with overwriting");
+#endif
+    }
+    ShouldNotReachHere();
+  }
+
+  void set_contended_group(u2 val) {
+    u2 lo = _shorts[low_packed_offset];
+    switch(lo & FIELDINFO_TAG_MASK) {
+      case FIELDINFO_TAG_TYPE_PLAIN:
+        _shorts[low_packed_offset] |= FIELDINFO_TAG_TYPE_CONTENDED;
+        _shorts[high_packed_offset] = val;
+        return;
+#ifndef PRODUCT
+      case FIELDINFO_TAG_TYPE_CONTENDED:
+        ShouldNotReachHere2("Overwriting contended group");
+      case FIELDINFO_TAG_BLANK:
+        ShouldNotReachHere2("Setting contended group for the blank field");
+      case FIELDINFO_TAG_OFFSET:
+        ShouldNotReachHere2("Setting contended group for field with offset");
+#endif
+    }
+    ShouldNotReachHere();
   }
 
   bool is_internal() const {
--- a/src/share/vm/oops/fieldStreams.hpp	Fri Jan 11 09:53:24 2013 -0800
+++ b/src/share/vm/oops/fieldStreams.hpp	Mon Jan 14 15:17:47 2013 +0100
@@ -160,9 +160,26 @@
     return field()->offset();
   }
 
+  int allocation_type() const {
+    return field()->allocation_type();
+  }
+
   void set_offset(int offset) {
     field()->set_offset(offset);
   }
+
+  bool is_offset_set() const {
+    return field()->is_offset_set();
+  }
+
+  bool is_contended() const {
+    return field()->is_contended();
+  }
+
+  int contended_group() const {
+    return field()->contended_group();
+  }
+
 };
 
 // Iterate over only the internal fields
--- a/src/share/vm/oops/instanceKlass.hpp	Fri Jan 11 09:53:24 2013 -0800
+++ b/src/share/vm/oops/instanceKlass.hpp	Mon Jan 14 15:17:47 2013 +0100
@@ -230,7 +230,8 @@
     _misc_rewritten            = 1 << 0, // methods rewritten.
     _misc_has_nonstatic_fields = 1 << 1, // for sizing with UseCompressedOops
     _misc_should_verify_class  = 1 << 2, // allow caching of preverification
-    _misc_is_anonymous         = 1 << 3  // has embedded _inner_classes field
+    _misc_is_anonymous         = 1 << 3, // has embedded _inner_classes field
+    _misc_is_contended         = 1 << 4  // marked with contended annotation
   };
   u2              _misc_flags;
   u2              _minor_version;        // minor version number of class file
@@ -550,6 +551,17 @@
     return is_anonymous() ? java_mirror() : class_loader();
   }
 
+  bool is_contended() const                {
+    return (_misc_flags & _misc_is_contended) != 0;
+  }
+  void set_is_contended(bool value)        {
+    if (value) {
+      _misc_flags |= _misc_is_contended;
+    } else {
+      _misc_flags &= ~_misc_is_contended;
+    }
+  }
+
   // signers
   objArrayOop signers() const              { return _signers; }
   void set_signers(objArrayOop s)          { klass_oop_store((oop*)&_signers, s); }
--- a/src/share/vm/runtime/globals.hpp	Fri Jan 11 09:53:24 2013 -0800
+++ b/src/share/vm/runtime/globals.hpp	Mon Jan 14 15:17:47 2013 +0100
@@ -1075,7 +1075,7 @@
                                                                             \
   product(intx, ClearFPUAtPark, 0, "(Unsafe,Unstable)" )                    \
                                                                             \
-  product(intx, hashCode, 0,                                                \
+  product(intx, hashCode, 5,                                                \
          "(Unstable) select hashCode generation algorithm" )                \
                                                                             \
   product(intx, WorkAroundNPTLTimedWaitHang, 1,                             \
@@ -1173,6 +1173,18 @@
   notproduct(bool, PrintCompactFieldsSavings, false,                        \
           "Print how many words were saved with CompactFields")             \
                                                                             \
+  notproduct(bool, PrintFieldLayout, false,                                 \
+          "Print field layout for each class")                              \
+                                                                            \
+  product(intx, ContendedPaddingWidth, 128,                                 \
+          "How many bytes to pad the fields/classes marked @Contended with")\
+                                                                            \
+  product(bool, EnableContended, true,                                      \
+          "Enable @Contended annotation support")                           \
+                                                                            \
+  product(bool, RestrictContended, true,                                    \
+          "Restrict @Contended to trusted classes")                         \
+                                                                            \
   product(bool, UseBiasedLocking, true,                                     \
           "Enable biased locking in JVM")                                   \
                                                                             \
--- a/src/share/vm/runtime/vmStructs.cpp	Fri Jan 11 09:53:24 2013 -0800
+++ b/src/share/vm/runtime/vmStructs.cpp	Mon Jan 14 15:17:47 2013 +0100
@@ -2284,10 +2284,17 @@
   declare_constant(FieldInfo::name_index_offset)                          \
   declare_constant(FieldInfo::signature_index_offset)                     \
   declare_constant(FieldInfo::initval_index_offset)                       \
-  declare_constant(FieldInfo::low_offset)                                 \
-  declare_constant(FieldInfo::high_offset)                                \
+  declare_constant(FieldInfo::low_packed_offset)                          \
+  declare_constant(FieldInfo::high_packed_offset)                         \
   declare_constant(FieldInfo::field_slots)                                \
                                                                           \
+  /*************************************/                                 \
+  /* FieldInfo tag constants           */                                 \
+  /*************************************/                                 \
+                                                                          \
+  declare_preprocessor_constant("FIELDINFO_TAG_SIZE", FIELDINFO_TAG_SIZE) \
+  declare_preprocessor_constant("FIELDINFO_TAG_OFFSET", FIELDINFO_TAG_OFFSET) \
+                                                                          \
   /************************************************/                      \
   /* InstanceKlass InnerClassAttributeOffset enum */                      \
   /************************************************/                      \