jmasa@4196: /*
stefank@5941:  * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
jmasa@4196:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
jmasa@4196:  *
jmasa@4196:  * This code is free software; you can redistribute it and/or modify it
jmasa@4196:  * under the terms of the GNU General Public License version 2 only, as
jmasa@4196:  * published by the Free Software Foundation.
jmasa@4196:  *
jmasa@4196:  * This code is distributed in the hope that it will be useful, but WITHOUT
jmasa@4196:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
jmasa@4196:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
jmasa@4196:  * version 2 for more details (a copy is included in the LICENSE file that
jmasa@4196:  * accompanied this code).
jmasa@4196:  *
jmasa@4196:  * You should have received a copy of the GNU General Public License version
jmasa@4196:  * 2 along with this work; if not, write to the Free Software Foundation,
jmasa@4196:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
jmasa@4196:  *
jmasa@4196:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
jmasa@4196:  * or visit www.oracle.com if you need additional information or have any
jmasa@4196:  * questions.
jmasa@4196:  *
jmasa@4196:  */
jmasa@4196: #ifndef SHARE_VM_MEMORY_METACHUNK_HPP
jmasa@4196: #define SHARE_VM_MEMORY_METACHUNK_HPP
jmasa@4196: 
stefank@5941: #include "memory/allocation.hpp"
stefank@5941: #include "utilities/debug.hpp"
stefank@5941: #include "utilities/globalDefinitions.hpp"
jmasa@4196: 
jmasa@5007: class VirtualSpaceNode;
jmasa@5007: 
stefank@5941: // Super class of Metablock and Metachunk to allow them to
stefank@5941: // be put on the FreeList and in the BinaryTreeDictionary.
stefank@5941: template <class T>
stefank@5941: class Metabase VALUE_OBJ_CLASS_SPEC {
stefank@5941:   size_t _word_size;
stefank@5941:   T*     _next;
stefank@5941:   T*     _prev;
jmasa@4196: 
stefank@5941:  protected:
stefank@5941:   Metabase(size_t word_size) : _word_size(word_size), _next(NULL), _prev(NULL) {}
jmasa@4196: 
jmasa@4196:  public:
stefank@5941:   T* next() const         { return _next; }
stefank@5941:   T* prev() const         { return _prev; }
stefank@5941:   void set_next(T* v)     { _next = v; assert(v != this, "Boom");}
stefank@5941:   void set_prev(T* v)     { _prev = v; assert(v != this, "Boom");}
stefank@5941:   void clear_next()       { set_next(NULL); }
stefank@5941:   void clear_prev()       { set_prev(NULL); }
jmasa@4196: 
jmasa@4196:   size_t size() const volatile { return _word_size; }
jmasa@4196:   void set_size(size_t v) { _word_size = v; }
stefank@5941: 
stefank@5941:   void link_next(T* ptr)  { set_next(ptr); }
stefank@5941:   void link_prev(T* ptr)  { set_prev(ptr); }
stefank@5941:   void link_after(T* ptr) {
jmasa@4196:     link_next(ptr);
stefank@5941:     if (ptr != NULL) ptr->link_prev((T*)this);
jmasa@4196:   }
jmasa@4196: 
stefank@5941:   uintptr_t* end() const        { return ((uintptr_t*) this) + size(); }
jmasa@4196: 
stefank@5941:   bool cantCoalesce() const     { return false; }
jmasa@4196: 
jmasa@4196:   // Debug support
jmasa@4196: #ifdef ASSERT
jmasa@4196:   void* prev_addr() const { return (void*)&_prev; }
jmasa@4196:   void* next_addr() const { return (void*)&_next; }
jmasa@4196:   void* size_addr() const { return (void*)&_word_size; }
jmasa@4196: #endif
stefank@5941:   bool verify_chunk_in_free_list(T* tc) const { return true; }
jmasa@4196:   bool verify_par_locked() { return true; }
jmasa@4196: 
jmasa@4196:   void assert_is_mangled() const {/* Don't check "\*/}
jmasa@4196: 
stefank@5941:   bool is_free()                 { return true; }
stefank@5941: };
stefank@5941: 
stefank@5941: //  Metachunk - Quantum of allocation from a Virtualspace
stefank@5941: //    Metachunks are reused (when freed are put on a global freelist) and
stefank@5941: //    have no permanent association to a SpaceManager.
stefank@5941: 
stefank@5941: //            +--------------+ <- end    --+       --+
stefank@5941: //            |              |             |         |
stefank@5941: //            |              |             | free    |
stefank@5941: //            |              |             |         |
stefank@5941: //            |              |             |         | size | capacity
stefank@5941: //            |              |             |         |
stefank@5941: //            |              | <- top   -- +         |
stefank@5941: //            |              |             |         |
stefank@5941: //            |              |             | used    |
stefank@5941: //            |              |             |         |
stefank@5941: //            |              |             |         |
stefank@5941: //            +--------------+ <- bottom --+       --+
stefank@5941: 
stefank@5941: class Metachunk : public Metabase<Metachunk> {
stefank@5941:   friend class TestMetachunk;
stefank@5941:   // The VirtualSpaceNode containing this chunk.
stefank@5941:   VirtualSpaceNode* _container;
stefank@5941: 
stefank@5941:   // Current allocation top.
stefank@5941:   MetaWord* _top;
stefank@5941: 
stefank@5941:   DEBUG_ONLY(bool _is_tagged_free;)
stefank@5941: 
stefank@5941:   MetaWord* initial_top() const { return (MetaWord*)this + overhead(); }
stefank@5941:   MetaWord* top() const         { return _top; }
stefank@5941: 
stefank@5941:  public:
stefank@5941:   // Metachunks are allocated out of a MetadataVirtualSpace and
stefank@5941:   // and use some of its space to describe itself (plus alignment
stefank@5941:   // considerations).  Metadata is allocated in the rest of the chunk.
stefank@5941:   // This size is the overhead of maintaining the Metachunk within
stefank@5941:   // the space.
stefank@5941: 
stefank@5941:   // Alignment of each allocation in the chunks.
stefank@5941:   static size_t object_alignment();
stefank@5941: 
stefank@5941:   // Size of the Metachunk header, including alignment.
stefank@5941:   static size_t overhead();
stefank@5941: 
stefank@5941:   Metachunk(size_t word_size , VirtualSpaceNode* container);
stefank@5941: 
stefank@5941:   MetaWord* allocate(size_t word_size);
stefank@5941: 
stefank@5941:   VirtualSpaceNode* container() const { return _container; }
stefank@5941: 
stefank@5941:   MetaWord* bottom() const { return (MetaWord*) this; }
stefank@5941: 
stefank@5941:   // Reset top to bottom so chunk can be reused.
stefank@5941:   void reset_empty() { _top = initial_top(); clear_next(); clear_prev(); }
stefank@5941:   bool is_empty() { return _top == initial_top(); }
stefank@5941: 
stefank@5941:   // used (has been allocated)
stefank@5941:   // free (available for future allocations)
stefank@5941:   size_t word_size() const { return size(); }
stefank@5941:   size_t used_word_size() const;
stefank@5941:   size_t free_word_size() const;
stefank@5941: 
stefank@5941: #ifdef ASSERT
stefank@5941:   bool is_tagged_free() { return _is_tagged_free; }
stefank@5941:   void set_is_tagged_free(bool v) { _is_tagged_free = v; }
stefank@5941: #endif
jmasa@4196: 
coleenp@6305:   bool contains(const void* ptr) { return bottom() <= ptr && ptr < _top; }
coleenp@6305: 
stefank@5944:   NOT_PRODUCT(void mangle();)
stefank@5944: 
jmasa@4196:   void print_on(outputStream* st) const;
jmasa@4196:   void verify();
jmasa@4196: };
stefank@5941: 
stefank@5941: // Metablock is the unit of allocation from a Chunk.
stefank@5941: //
stefank@5941: // A Metablock may be reused by its SpaceManager but are never moved between
stefank@5941: // SpaceManagers.  There is no explicit link to the Metachunk
stefank@5941: // from which it was allocated.  Metablock may be deallocated and
stefank@5941: // put on a freelist but the space is never freed, rather
stefank@5941: // the Metachunk it is a part of will be deallocated when it's
stefank@5941: // associated class loader is collected.
stefank@5941: 
stefank@5941: class Metablock : public Metabase<Metablock> {
stefank@5941:   friend class VMStructs;
stefank@5941:  public:
stefank@5941:   Metablock(size_t word_size) : Metabase<Metablock>(word_size) {}
stefank@5941: };
stefank@5941: 
jmasa@4196: #endif  // SHARE_VM_MEMORY_METACHUNK_HPP