jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/shared/spaceDecorator.hpp@f90c822e73f8 (annotated)

src/share/vm/gc_implementation/shared/spaceDecorator.hpp@f90c822e73f8 (annotated)

src/share/vm/gc_implementation/shared/spaceDecorator.hpp

Wed, 27 Apr 2016 01:25:04 +0800

author: aoqi
date: Wed, 27 Apr 2016 01:25:04 +0800
changeset 0: f90c822e73f8
child 6876: 710a3c8b516e
permissions: -rw-r--r--

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http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/
changeset: 6782:28b50d07f6f8
tag: jdk8u25-b17

 /*
  * Copyright (c) 2002, 2012, 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_SHARED_SPACEDECORATOR_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_SPACEDECORATOR_HPP
 #include "gc_implementation/shared/mutableSpace.hpp"
 #include "memory/space.hpp"
 #include "utilities/globalDefinitions.hpp"
 class SpaceDecorator: public AllStatic {
  public:
   // Initialization flags.
   static const bool Clear               = true;
   static const bool DontClear           = false;
   static const bool Mangle              = true;
   static const bool DontMangle          = false;
 };
 // Functionality for use with class Space and class MutableSpace.
 //   The approach taken with the mangling is to mangle all
 // the space initially and then to mangle areas that have
 // been allocated since the last collection.  Mangling is
 // done in the context of a generation and in the context
 // of a space.
 //   The space in a generation is mangled when it is first
 // initialized and when the generation grows.  The spaces
 // are not necessarily up-to-date when this mangling occurs
 // and the method mangle_region() is used.
 //   After allocations have been done in a space, the space generally
 // need to be remangled.  Remangling is only done on the
 // recently allocated regions in the space.  Typically, that is
 // the region between the new top and the top just before a
 // garbage collection.
 //   An exception to the usual mangling in a space is done when the
 // space is used for an extraordinary purpose.  Specifically, when
 // to-space is used as scratch space for a mark-sweep-compact
 // collection.
 //   Spaces are mangled after a collection.  If the generation
 // grows after a collection, the added space is mangled as part of
 // the growth of the generation.  No additional mangling is needed when the
 // spaces are resized after an expansion.
 //   The class SpaceMangler keeps a pointer to the top of the allocated
 // area and provides the methods for doing the piece meal mangling.
 // Methods for doing sparces and full checking of the mangling are
 // included.  The full checking is done if DEBUG_MANGLING is defined.
 //   GenSpaceMangler is used with the GenCollectedHeap collectors and
 // MutableSpaceMangler is used with the ParallelScavengeHeap collectors.
 // These subclasses abstract the differences in the types of spaces used
 // by each heap.
 class SpaceMangler: public CHeapObj<mtGC> {
   friend class VMStructs;
   // High water mark for allocations.  Typically, the space above
   // this point have been mangle previously and don't need to be
   // touched again.  Space belows this point has been allocated
   // and remangling is needed between the current top and this
   // high water mark.
   HeapWord* _top_for_allocations;
   HeapWord* top_for_allocations() { return _top_for_allocations; }
  public:
   // Setting _top_for_allocations to NULL at initialization
   // makes it always below top so that mangling done as part
   // of the initialize() call of a space does nothing (as it
   // should since the mangling is done as part of the constructor
   // for the space.
   SpaceMangler() : _top_for_allocations(NULL) {}
   // Methods for top and end that delegate to the specific
   // space type.
   virtual HeapWord* top() const = 0;
   virtual HeapWord* end() const = 0;
   // Return true if q matches the mangled pattern.
   static bool is_mangled(HeapWord* q) PRODUCT_RETURN0;
   // Used to save the an address in a space for later use during mangling.
   void set_top_for_allocations(HeapWord* v);
   // Overwrites the unused portion of this space.
   // Mangle only the region not previously mangled [top, top_previously_mangled)
   void mangle_unused_area();
   // Mangle all the unused region [top, end)
   void mangle_unused_area_complete();
   // Do some sparse checking on the area that should have been mangled.
   void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN;
   // Do a complete check of the area that should be mangled.
   void check_mangled_unused_area_complete() PRODUCT_RETURN;
   // Mangle the MemRegion.  This is a non-space specific mangler.  It
   // is used during the initial mangling of a space before the space
   // is fully constructed.  Also is used when a generation is expanded
   // and possibly before the spaces have been reshaped to to the new
   // size of the generation.
   static void mangle_region(MemRegion mr) PRODUCT_RETURN;
 };
 class ContiguousSpace;
 // For use with GenCollectedHeap's
 class GenSpaceMangler: public SpaceMangler {
   ContiguousSpace* _sp;
   ContiguousSpace* sp() { return _sp; }
   HeapWord* top() const { return _sp->top(); }
   HeapWord* end() const { return _sp->end(); }
  public:
   GenSpaceMangler(ContiguousSpace* sp) : SpaceMangler(), _sp(sp) {}
 };
 // For use with ParallelScavengeHeap's.
 class MutableSpaceMangler: public SpaceMangler {
   MutableSpace* _sp;
   MutableSpace* sp() { return _sp; }
   HeapWord* top() const { return _sp->top(); }
   HeapWord* end() const { return _sp->end(); }
  public:
   MutableSpaceMangler(MutableSpace* sp) : SpaceMangler(), _sp(sp) {}
 };
 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_SPACEDECORATOR_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/shared/spaceDecorator.hpp@f90c822e73f8 (annotated)

src/share/vm/gc_implementation/shared/spaceDecorator.hpp