view src/share/vm/classfile/loaderConstraints.hpp @ 2149:7e37af9d69ef

7011379: G1: overly long concurrent marking cycles Summary: This changeset introduces filtering of SATB buffers at the point when they are about to be enqueued. If this filtering clears enough entries on each buffer, the buffer can then be re-used and not enqueued. This cuts down the number of SATB buffers that need to be processed by the concurrent marking threads. Reviewed-by: johnc, ysr
author tonyp
date Wed, 19 Jan 2011 09:35:17 -0500
parents f95d63e2154a
children 3582bf76420e
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/*
 * Copyright (c) 2003, 2010, 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
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#ifndef SHARE_VM_CLASSFILE_LOADERCONSTRAINTS_HPP
#define SHARE_VM_CLASSFILE_LOADERCONSTRAINTS_HPP

#include "classfile/dictionary.hpp"
#include "classfile/placeholders.hpp"
#include "utilities/hashtable.hpp"

class LoaderConstraintEntry;

class LoaderConstraintTable : public Hashtable {
  friend class VMStructs;
private:

  enum Constants {
    _loader_constraint_size = 107,                     // number of entries in constraint table
    _nof_buckets            = 1009                     // number of buckets in hash table
  };

  LoaderConstraintEntry** find_loader_constraint(symbolHandle name,
                                                 Handle loader);

public:

  LoaderConstraintTable(int nof_buckets);

  LoaderConstraintEntry* new_entry(unsigned int hash, symbolOop name,
                                   klassOop klass, int num_loaders,
                                   int max_loaders);

  LoaderConstraintEntry* bucket(int i) {
    return (LoaderConstraintEntry*)Hashtable::bucket(i);
  }

  LoaderConstraintEntry** bucket_addr(int i) {
    return (LoaderConstraintEntry**)Hashtable::bucket_addr(i);
  }

  // GC support
  void oops_do(OopClosure* f);
  void always_strong_classes_do(OopClosure* blk);

  // Check class loader constraints
  bool add_entry(symbolHandle name, klassOop klass1, Handle loader1,
                                    klassOop klass2, Handle loader2);

  // Note:  The main entry point for this module is via SystemDictionary.
  // SystemDictionary::check_signature_loaders(symbolHandle signature,
  //                                           Handle loader1, Handle loader2,
  //                                           bool is_method, TRAPS)

  klassOop find_constrained_klass(symbolHandle name, Handle loader);

  // Class loader constraints

  void ensure_loader_constraint_capacity(LoaderConstraintEntry *p, int nfree);
  void extend_loader_constraint(LoaderConstraintEntry* p, Handle loader,
                                klassOop klass);
  void merge_loader_constraints(LoaderConstraintEntry** pp1,
                                LoaderConstraintEntry** pp2, klassOop klass);

  bool check_or_update(instanceKlassHandle k, Handle loader,
                              symbolHandle name);


  void purge_loader_constraints(BoolObjectClosure* is_alive);

  void verify(Dictionary* dictionary, PlaceholderTable* placeholders);
#ifndef PRODUCT
  void print();
#endif
};

class LoaderConstraintEntry : public HashtableEntry {
  friend class VMStructs;
private:
  symbolOop              _name;                   // class name
  int                    _num_loaders;
  int                    _max_loaders;
  oop*                   _loaders;                // initiating loaders

public:

  klassOop klass() { return (klassOop)literal(); }
  klassOop* klass_addr() { return (klassOop*)literal_addr(); }
  void set_klass(klassOop k) { set_literal(k); }

  LoaderConstraintEntry* next() {
    return (LoaderConstraintEntry*)HashtableEntry::next();
  }

  LoaderConstraintEntry** next_addr() {
    return (LoaderConstraintEntry**)HashtableEntry::next_addr();
  }
  void set_next(LoaderConstraintEntry* next) {
    HashtableEntry::set_next(next);
  }

  symbolOop name() { return _name; }
  symbolOop* name_addr() { return &_name; }
  void set_name(symbolOop name) { _name = name; }

  int num_loaders() { return _num_loaders; }
  void set_num_loaders(int i) { _num_loaders = i; }

  int max_loaders() { return _max_loaders; }
  void set_max_loaders(int i) { _max_loaders = i; }

  oop* loaders() { return _loaders; }
  void set_loaders(oop* loaders) { _loaders = loaders; }

  oop loader(int i) { return _loaders[i]; }
  oop* loader_addr(int i) { return &_loaders[i]; }
  void set_loader(int i, oop p) { _loaders[i] = p; }

};

#endif // SHARE_VM_CLASSFILE_LOADERCONSTRAINTS_HPP