--- old/src/share/vm/memory/metachunk.hpp 2013-10-14 13:25:57.744551085 +0200 +++ new/src/share/vm/memory/metachunk.hpp 2013-10-14 13:25:57.644551088 +0200 @@ -24,104 +24,143 @@ #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 Metamem VALUE_OBJ_CLASS_SPEC { + size_t _word_size; + T* _next; + T* _prev; + + protected: + Metamem(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 | -// | | | | -// | | | | capacity -// | | | | -// | | <- top --+ | -// | | ---+ | -// | | | used | -// | | | | -// | | | | -// +--------------+ <- bottom ---+ ---+ - -class VirtualSpaceNode; - -class Metachunk VALUE_OBJ_CLASS_SPEC { - // link to support lists of chunks - Metachunk* _next; - Metachunk* _prev; +// +--------------+ <- end --+ --+ +// | | | | +// | | | free | +// | | | | +// | | | | size | capacity +// | | | | +// | | <- top -- + | +// | | | | +// | | | used | +// | | | | +// | | | | +// +--------------+ <- bottom --+ --+ + +class Metachunk : public Metamem { + friend class TestMetachunk; + // The VirtualSpaceNode containing this chunk. VirtualSpaceNode* _container; - MetaWord* _bottom; - MetaWord* _end; + // Current allocation top. MetaWord* _top; - size_t _word_size; - // Used in a guarantee() so included in the Product builds - // even through it is only for debugging. - bool _is_free; + DEBUG_ONLY(bool _is_marked_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. - static size_t _overhead; - public: - Metachunk(size_t word_size , VirtualSpaceNode* container); + // Alignment of each allocation in the chunks. + static size_t object_alignment(); - // Used to add a Metachunk to a list of Metachunks - void set_next(Metachunk* v) { _next = v; assert(v != this, "Boom");} - void set_prev(Metachunk* v) { _prev = v; assert(v != this, "Boom");} - void set_container(VirtualSpaceNode* v) { _container = v; } + // Size of the Metachunk header, including alignment. + static size_t overhead(); + + Metachunk(size_t word_size , VirtualSpaceNode* container); MetaWord* allocate(size_t word_size); - // Accessors - Metachunk* next() const { return _next; } - Metachunk* prev() const { return _prev; } VirtualSpaceNode* container() const { return _container; } - MetaWord* bottom() const { return _bottom; } - MetaWord* end() const { return _end; } - MetaWord* top() const { return _top; } - size_t word_size() const { return _word_size; } - size_t size() const volatile { return _word_size; } - void set_size(size_t v) { _word_size = v; } - bool is_free() { return _is_free; } - void set_is_free(bool v) { _is_free = v; } - static size_t overhead() { return _overhead; } - void clear_next() { set_next(NULL); } - void link_prev(Metachunk* ptr) { set_prev(ptr); } - uintptr_t* end() { return ((uintptr_t*) this) + size(); } - bool cantCoalesce() const { return false; } - void link_next(Metachunk* ptr) { set_next(ptr); } - void link_after(Metachunk* ptr){ - link_next(ptr); - if (ptr != NULL) ptr->link_prev(this); - } + + MetaWord* bottom() const { return (MetaWord*) this; } // Reset top to bottom so chunk can be reused. - void reset_empty() { _top = (_bottom + _overhead); _next = NULL; _prev = NULL; } - bool is_empty() { return _top == (_bottom + _overhead); } + 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) - // capacity (total size of chunk) + size_t word_size() const { return size(); } size_t used_word_size() const; size_t free_word_size() const; - size_t capacity_word_size()const; - // 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; } + void mangle(); + bool is_marked_free() { return _is_marked_free; } + void set_is_marked_free(bool v) { _is_marked_free = v; } #endif - bool verify_chunk_in_free_list(Metachunk* tc) const { return true; } - bool verify_par_locked() { return true; } - - void assert_is_mangled() const {/* Don't check "\*/} - - 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 Metamem { + friend class VMStructs; + public: + Metablock(size_t word_size) : Metamem(word_size) {} +}; + #endif // SHARE_VM_MEMORY_METACHUNK_HPP