view src/share/vm/oops/cpCacheKlass.cpp @ 3917:eca1193ca245

4965777: GC changes to support use of discovered field for pending references Summary: If and when the reference handler thread is able to use the discovered field to link reference objects in its pending list, so will GC. In that case, GC will scan through this field once a reference object has been placed on the pending list, but not scan that field before that stage, as the field is used by the concurrent GC thread to link discovered objects. When ReferenceHandleR thread does not use the discovered field for the purpose of linking the elements in the pending list, as would be the case in older JDKs, the JVM will fall back to the old behaviour of using the next field for that purpose. Reviewed-by: jcoomes, mchung, stefank
author ysr
date Wed, 07 Sep 2011 13:55:42 -0700
parents c7f3d0b4570f
children baf763f388e6
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/*
 * Copyright (c) 1998, 2011, 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 "precompiled.hpp"
#include "classfile/javaClasses.hpp"
#include "gc_implementation/shared/markSweep.inline.hpp"
#include "gc_interface/collectedHeap.hpp"
#include "interpreter/bytecodes.hpp"
#include "memory/genOopClosures.inline.hpp"
#include "memory/permGen.hpp"
#include "oops/constantPoolOop.hpp"
#include "oops/cpCacheKlass.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/handles.inline.hpp"
#ifndef SERIALGC
#include "gc_implementation/parNew/parOopClosures.inline.hpp"
#include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
#include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
#include "memory/cardTableRS.hpp"
#include "oops/oop.pcgc.inline.hpp"
#endif


int constantPoolCacheKlass::oop_size(oop obj) const {
  assert(obj->is_constantPoolCache(), "must be constantPool");
  return constantPoolCacheOop(obj)->object_size();
}


constantPoolCacheOop constantPoolCacheKlass::allocate(int length,
                                                      TRAPS) {
  // allocate memory
  int size = constantPoolCacheOopDesc::object_size(length);

  KlassHandle klass (THREAD, as_klassOop());

  // Commented out below is the original code.  The code from
  // permanent_obj_allocate() was in-lined so that we could
  // set the _length field, necessary to correctly compute its
  // size(), before setting its klass word further below.
  // constantPoolCacheOop cache = (constantPoolCacheOop)
  //   CollectedHeap::permanent_obj_allocate(klass, size, CHECK_NULL);

  oop obj = CollectedHeap::permanent_obj_allocate_no_klass_install(klass, size, CHECK_NULL);
  NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value((HeapWord*) obj,
                                                              size));
  constantPoolCacheOop cache = (constantPoolCacheOop) obj;
  assert(!UseConcMarkSweepGC || obj->klass_or_null() == NULL,
         "klass should be NULL here when using CMS");
  cache->set_length(length);  // should become visible before klass is set below.
  cache->set_constant_pool(NULL);

  OrderAccess::storestore();
  obj->set_klass(klass());
  assert(cache->size() == size, "Incorrect cache->size()");
  return cache;
}

klassOop constantPoolCacheKlass::create_klass(TRAPS) {
  constantPoolCacheKlass o;
  KlassHandle h_this_klass(THREAD, Universe::klassKlassObj());
  KlassHandle k = base_create_klass(h_this_klass, header_size(), o.vtbl_value(), CHECK_NULL);
  // Make sure size calculation is right
  assert(k()->size() == align_object_size(header_size()), "wrong size for object");
  java_lang_Class::create_mirror(k, CHECK_NULL); // Allocate mirror
  return k();
}


void constantPoolCacheKlass::oop_follow_contents(oop obj) {
  assert(obj->is_constantPoolCache(), "obj must be constant pool cache");
  constantPoolCacheOop cache = (constantPoolCacheOop)obj;
  // Performance tweak: We skip iterating over the klass pointer since we
  // know that Universe::constantPoolCacheKlassObj never moves.
  // gc of constant pool cache instance variables
  MarkSweep::mark_and_push((oop*)cache->constant_pool_addr());
  // gc of constant pool cache entries
  int i = cache->length();
  while (i-- > 0) cache->entry_at(i)->follow_contents();
}

#ifndef SERIALGC
void constantPoolCacheKlass::oop_follow_contents(ParCompactionManager* cm,
                                                 oop obj) {
  assert(obj->is_constantPoolCache(), "obj must be constant pool cache");
  constantPoolCacheOop cache = (constantPoolCacheOop)obj;
  // Performance tweak: We skip iterating over the klass pointer since we
  // know that Universe::constantPoolCacheKlassObj never moves.
  // gc of constant pool cache instance variables
  PSParallelCompact::mark_and_push(cm, (oop*)cache->constant_pool_addr());
  // gc of constant pool cache entries
  int i = cache->length();
  while (i-- > 0) cache->entry_at(i)->follow_contents(cm);
}
#endif // SERIALGC


int constantPoolCacheKlass::oop_oop_iterate(oop obj, OopClosure* blk) {
  assert(obj->is_constantPoolCache(), "obj must be constant pool cache");
  constantPoolCacheOop cache = (constantPoolCacheOop)obj;
  // Get size before changing pointers.
  // Don't call size() or oop_size() since that is a virtual call.
  int size = cache->object_size();
  // Performance tweak: We skip iterating over the klass pointer since we
  // know that Universe::constantPoolCacheKlassObj never moves.
  // iteration over constant pool cache instance variables
  blk->do_oop((oop*)cache->constant_pool_addr());
  // iteration over constant pool cache entries
  for (int i = 0; i < cache->length(); i++) cache->entry_at(i)->oop_iterate(blk);
  return size;
}


int constantPoolCacheKlass::oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) {
  assert(obj->is_constantPoolCache(), "obj must be constant pool cache");
  constantPoolCacheOop cache = (constantPoolCacheOop)obj;
  // Get size before changing pointers.
  // Don't call size() or oop_size() since that is a virtual call.
  int size = cache->object_size();
  // Performance tweak: We skip iterating over the klass pointer since we
  // know that Universe::constantPoolCacheKlassObj never moves.
  // iteration over constant pool cache instance variables
  oop* addr = (oop*)cache->constant_pool_addr();
  if (mr.contains(addr)) blk->do_oop(addr);
  // iteration over constant pool cache entries
  for (int i = 0; i < cache->length(); i++) cache->entry_at(i)->oop_iterate_m(blk, mr);
  return size;
}

int constantPoolCacheKlass::oop_adjust_pointers(oop obj) {
  assert(obj->is_constantPoolCache(), "obj must be constant pool cache");
  constantPoolCacheOop cache = (constantPoolCacheOop)obj;
  // Get size before changing pointers.
  // Don't call size() or oop_size() since that is a virtual call.
  int size = cache->object_size();
  // Performance tweak: We skip iterating over the klass pointer since we
  // know that Universe::constantPoolCacheKlassObj never moves.
  // Iteration over constant pool cache instance variables
  MarkSweep::adjust_pointer((oop*)cache->constant_pool_addr());
  // iteration over constant pool cache entries
  for (int i = 0; i < cache->length(); i++)
    cache->entry_at(i)->adjust_pointers();
  return size;
}

#ifndef SERIALGC
void constantPoolCacheKlass::oop_push_contents(PSPromotionManager* pm,
                                               oop obj) {
  assert(obj->is_constantPoolCache(), "should be constant pool");
  if (ScavengeRootsInCode) {
    constantPoolCacheOop cache = (constantPoolCacheOop)obj;
    // during a scavenge, it is safe to inspect my pool, since it is perm
    constantPoolOop pool = cache->constant_pool();
    assert(pool->is_constantPool(), "should be constant pool");
    for (int i = 0; i < cache->length(); i++) {
      ConstantPoolCacheEntry* e = cache->entry_at(i);
      oop* p = (oop*)&e->_f1;
      if (PSScavenge::should_scavenge(p))
        pm->claim_or_forward_depth(p);
      assert(!(e->is_vfinal() && PSScavenge::should_scavenge((oop*)&e->_f2)),
             "no live oops here");
    }
  }
}

int
constantPoolCacheKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
  assert(obj->is_constantPoolCache(), "obj must be constant pool cache");
  constantPoolCacheOop cache = (constantPoolCacheOop)obj;

  // Iteration over constant pool cache instance variables
  PSParallelCompact::adjust_pointer((oop*)cache->constant_pool_addr());

  // iteration over constant pool cache entries
  for (int i = 0; i < cache->length(); ++i) {
    cache->entry_at(i)->update_pointers();
  }

  return cache->object_size();
}
#endif // SERIALGC

void constantPoolCacheKlass::oop_print_on(oop obj, outputStream* st) {
  assert(obj->is_constantPoolCache(), "obj must be constant pool cache");
  constantPoolCacheOop cache = (constantPoolCacheOop)obj;
  // super print
  Klass::oop_print_on(obj, st);
  // print constant pool cache entries
  for (int i = 0; i < cache->length(); i++) cache->entry_at(i)->print(st, i);
}

void constantPoolCacheKlass::oop_print_value_on(oop obj, outputStream* st) {
  assert(obj->is_constantPoolCache(), "obj must be constant pool cache");
  constantPoolCacheOop cache = (constantPoolCacheOop)obj;
  st->print("cache [%d]", cache->length());
  cache->print_address_on(st);
  st->print(" for ");
  cache->constant_pool()->print_value_on(st);
}

void constantPoolCacheKlass::oop_verify_on(oop obj, outputStream* st) {
  guarantee(obj->is_constantPoolCache(), "obj must be constant pool cache");
  constantPoolCacheOop cache = (constantPoolCacheOop)obj;
  // super verify
  Klass::oop_verify_on(obj, st);
  // print constant pool cache entries
  for (int i = 0; i < cache->length(); i++) cache->entry_at(i)->verify(st);
}


const char* constantPoolCacheKlass::internal_name() const {
  return "{constant pool cache}";
}