jdk8-mips64-public/hotspot: src/share/vm/memory/metachunk.hpp@7ae4e26cb1e0 (annotated)

src/share/vm/memory/metachunk.hpp@7ae4e26cb1e0 (annotated)

src/share/vm/memory/metachunk.hpp

Thu, 12 Oct 2017 21:27:07 +0800

author: aoqi
date: Thu, 12 Oct 2017 21:27:07 +0800
changeset 7535: 7ae4e26cb1e0
parent 6876: 710a3c8b516e
permissions: -rw-r--r--

merge

 /*
  * Copyright (c) 2012, 2013, 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_MEMORY_METACHUNK_HPP
 #define SHARE_VM_MEMORY_METACHUNK_HPP
 #include "memory/allocation.hpp"
 #include "utilities/debug.hpp"
 #include "utilities/globalDefinitions.hpp"
 class VirtualSpaceNode;
 // Super class of Metablock and Metachunk to allow them to
 // be put on the FreeList and in the BinaryTreeDictionary.
 template <class T>
 class Metabase VALUE_OBJ_CLASS_SPEC {
   size_t _word_size;
   T*     _next;
   T*     _prev;
  protected:
   Metabase(size_t word_size) : _word_size(word_size), _next(NULL), _prev(NULL) {}
  public:
   T* next() const         { return _next; }
   T* prev() const         { return _prev; }
   void set_next(T* v)     { _next = v; assert(v != this, "Boom");}
   void set_prev(T* v)     { _prev = v; assert(v != this, "Boom");}
   void clear_next()       { set_next(NULL); }
   void clear_prev()       { set_prev(NULL); }
   size_t size() const volatile { return _word_size; }
   void set_size(size_t v) { _word_size = v; }
   void link_next(T* ptr)  { set_next(ptr); }
   void link_prev(T* ptr)  { set_prev(ptr); }
   void link_after(T* ptr) {
     link_next(ptr);
     if (ptr != NULL) ptr->link_prev((T*)this);
   }
   uintptr_t* end() const        { return ((uintptr_t*) this) + size(); }
   bool cantCoalesce() const     { return false; }
   // Debug support
 #ifdef ASSERT
   void* prev_addr() const { return (void*)&_prev; }
   void* next_addr() const { return (void*)&_next; }
   void* size_addr() const { return (void*)&_word_size; }
 #endif
   bool verify_chunk_in_free_list(T* tc) const { return true; }
   bool verify_par_locked() { return true; }
   void assert_is_mangled() const {/* Don't check "\*/}
   bool is_free()                 { return true; }
 };
 //  Metachunk - Quantum of allocation from a Virtualspace
 //    Metachunks are reused (when freed are put on a global freelist) and
 //    have no permanent association to a SpaceManager.
 //            +--------------+ <- end    --+       --+
 //            |              |             |         |
 //            |              |             | free    |
 //            |              |             |         |
 //            |              |             |         | size | capacity
 //            |              |             |         |
 //            |              | <- top   -- +         |
 //            |              |             |         |
 //            |              |             | used    |
 //            |              |             |         |
 //            |              |             |         |
 //            +--------------+ <- bottom --+       --+
 class Metachunk : public Metabase<Metachunk> {
   friend class TestMetachunk;
   // The VirtualSpaceNode containing this chunk.
   VirtualSpaceNode* _container;
   // Current allocation top.
   MetaWord* _top;
   DEBUG_ONLY(bool _is_tagged_free;)
   MetaWord* initial_top() const { return (MetaWord*)this + overhead(); }
   MetaWord* top() const         { return _top; }
  public:
   // Metachunks are allocated out of a MetadataVirtualSpace and
   // and use some of its space to describe itself (plus alignment
   // considerations).  Metadata is allocated in the rest of the chunk.
   // This size is the overhead of maintaining the Metachunk within
   // the space.
   // Alignment of each allocation in the chunks.
   static size_t object_alignment();
   // Size of the Metachunk header, including alignment.
   static size_t overhead();
   Metachunk(size_t word_size , VirtualSpaceNode* container);
   MetaWord* allocate(size_t word_size);
   VirtualSpaceNode* container() const { return _container; }
   MetaWord* bottom() const { return (MetaWord*) this; }
   // Reset top to bottom so chunk can be reused.
   void reset_empty() { _top = initial_top(); clear_next(); clear_prev(); }
   bool is_empty() { return _top == initial_top(); }
   // used (has been allocated)
   // free (available for future allocations)
   size_t word_size() const { return size(); }
   size_t used_word_size() const;
   size_t free_word_size() const;
 #ifdef ASSERT
   bool is_tagged_free() { return _is_tagged_free; }
   void set_is_tagged_free(bool v) { _is_tagged_free = v; }
 #endif
   bool contains(const void* ptr) { return bottom() <= ptr && ptr < _top; }
   NOT_PRODUCT(void mangle();)
   void print_on(outputStream* st) const;
   void verify();
 };
 // Metablock is the unit of allocation from a Chunk.
 //
 // A Metablock may be reused by its SpaceManager but are never moved between
 // SpaceManagers.  There is no explicit link to the Metachunk
 // from which it was allocated.  Metablock may be deallocated and
 // put on a freelist but the space is never freed, rather
 // the Metachunk it is a part of will be deallocated when it's
 // associated class loader is collected.
 class Metablock : public Metabase<Metablock> {
   friend class VMStructs;
  public:
   Metablock(size_t word_size) : Metabase<Metablock>(word_size) {}
 };
 #endif  // SHARE_VM_MEMORY_METACHUNK_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/memory/metachunk.hpp@7ae4e26cb1e0 (annotated)

src/share/vm/memory/metachunk.hpp