| /* |
| * Copyright (c) 2012, 2016, 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 MetachunkTest; |
| // 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; } |
| |
| #ifndef PRODUCT |
| void mangle(juint word_value); |
| #endif |
| |
| 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 |