heap.hpp revision 5776:de6a9e811145
1218792Snp/* 2218792Snp * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. 3218792Snp * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4218792Snp * 5218792Snp * This code is free software; you can redistribute it and/or modify it 6218792Snp * under the terms of the GNU General Public License version 2 only, as 7218792Snp * published by the Free Software Foundation. 8218792Snp * 9218792Snp * This code is distributed in the hope that it will be useful, but WITHOUT 10218792Snp * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11218792Snp * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12218792Snp * version 2 for more details (a copy is included in the LICENSE file that 13218792Snp * accompanied this code). 14218792Snp * 15218792Snp * You should have received a copy of the GNU General Public License version 16218792Snp * 2 along with this work; if not, write to the Free Software Foundation, 17218792Snp * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18218792Snp * 19218792Snp * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20218792Snp * or visit www.oracle.com if you need additional information or have any 21218792Snp * questions. 22218792Snp * 23218792Snp */ 24218792Snp 25218792Snp#ifndef SHARE_VM_MEMORY_HEAP_HPP 26218792Snp#define SHARE_VM_MEMORY_HEAP_HPP 27218792Snp 28218792Snp#include "memory/allocation.hpp" 29218792Snp#include "runtime/virtualspace.hpp" 30218792Snp 31218792Snp// Blocks 32237819Snp 33218792Snpclass HeapBlock VALUE_OBJ_CLASS_SPEC { 34218792Snp friend class VMStructs; 35218792Snp 36218792Snp public: 37218792Snp struct Header { 38218792Snp size_t _length; // the length in segments 39218792Snp bool _used; // Used bit 40219286Snp }; 41219286Snp 42219286Snp protected: 43218792Snp union { 44218792Snp Header _header; 45218792Snp int64_t _padding[ (sizeof(Header) + sizeof(int64_t)-1) / sizeof(int64_t) ]; 46218792Snp // pad to 0 mod 8 47218792Snp }; 48219436Snp 49218792Snp public: 50218792Snp // Initialization 51218792Snp void initialize(size_t length) { _header._length = length; set_used(); } 52218792Snp 53218792Snp // Accessors 54218792Snp void* allocated_space() const { return (void*)(this + 1); } 55218792Snp size_t length() const { return _header._length; } 56218792Snp 57222003Snp // Used/free 58248925Snp void set_used() { _header._used = true; } 59248925Snp void set_free() { _header._used = false; } 60248925Snp bool free() { return !_header._used; } 61248925Snp}; 62218792Snp 63218792Snpclass FreeBlock: public HeapBlock { 64221474Snp friend class VMStructs; 65218792Snp protected: 66218792Snp FreeBlock* _link; 67218792Snp 68222509Snp public: 69218792Snp // Initialization 70218792Snp void initialize(size_t length) { HeapBlock::initialize(length); _link= NULL; } 71218792Snp 72218792Snp // Merging 73218792Snp void set_length(size_t l) { _header._length = l; } 74218792Snp 75218792Snp // Accessors 76218792Snp FreeBlock* link() const { return _link; } 77218792Snp void set_link(FreeBlock* link) { _link = link; } 78218792Snp}; 79227843Smarius 80218792Snpclass CodeHeap : public CHeapObj<mtCode> { 81218792Snp friend class VMStructs; 82218792Snp private: 83218792Snp VirtualSpace _memory; // the memory holding the blocks 84218792Snp VirtualSpace _segmap; // the memory holding the segment map 85218792Snp 86218792Snp size_t _number_of_committed_segments; 87218792Snp size_t _number_of_reserved_segments; 88218792Snp size_t _segment_size; 89218792Snp int _log2_segment_size; 90218792Snp 91218792Snp size_t _next_segment; 92218792Snp 93218792Snp FreeBlock* _freelist; 94218792Snp size_t _freelist_segments; // No. of segments in freelist 95218792Snp 96218792Snp // Helper functions 97218792Snp size_t size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; } 98218792Snp size_t segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; } 99218792Snp 100218792Snp size_t segment_for(void* p) const { return ((char*)p - _memory.low()) >> _log2_segment_size; } 101218792Snp HeapBlock* block_at(size_t i) const { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); } 102218792Snp 103218792Snp void mark_segmap_as_free(size_t beg, size_t end); 104218792Snp void mark_segmap_as_used(size_t beg, size_t end); 105218792Snp 106218792Snp // Freelist management helpers 107218792Snp FreeBlock* following_block(FreeBlock *b); 108218792Snp void insert_after(FreeBlock* a, FreeBlock* b); 109218792Snp void merge_right (FreeBlock* a); 110218792Snp 111218792Snp // Toplevel freelist management 112218792Snp void add_to_freelist(HeapBlock *b); 113218792Snp FreeBlock* search_freelist(size_t length, bool is_critical); 114218792Snp 115218792Snp // Iteration helpers 116218792Snp void* next_free(HeapBlock* b) const; 117248925Snp HeapBlock* first_block() const; 118248925Snp HeapBlock* next_block(HeapBlock* b) const; 119248925Snp HeapBlock* block_start(void* p) const; 120248925Snp 121248925Snp // to perform additional actions on creation of executable code 122248925Snp void on_code_mapping(char* base, size_t size); 123248925Snp 124248925Snp public: 125248925Snp CodeHeap(); 126248925Snp 127248925Snp // Heap extents 128248925Snp bool reserve(size_t reserved_size, size_t committed_size, size_t segment_size); 129248925Snp void release(); // releases all allocated memory 130248925Snp bool expand_by(size_t size); // expands commited memory by size 131248925Snp void shrink_by(size_t size); // shrinks commited memory by size 132248925Snp void clear(); // clears all heap contents 133248925Snp 134248925Snp // Memory allocation 135248925Snp void* allocate (size_t size, bool is_critical); // allocates a block of size or returns NULL 136248925Snp void deallocate(void* p); // deallocates a block 137248925Snp 138248925Snp // Attributes 139248925Snp char* low_boundary() const { return _memory.low_boundary (); } 140248925Snp char* high() const { return _memory.high(); } 141248925Snp char* high_boundary() const { return _memory.high_boundary(); } 142248925Snp 143248925Snp bool contains(const void* p) const { return low_boundary() <= p && p < high(); } 144248925Snp void* find_start(void* p) const; // returns the block containing p or NULL 145248925Snp size_t alignment_unit() const; // alignment of any block 146248925Snp size_t alignment_offset() const; // offset of first byte of any block, within the enclosing alignment unit 147248925Snp static size_t header_size(); // returns the header size for each heap block 148248925Snp 149218792Snp // Iteration 150218792Snp 151218792Snp // returns the first block or NULL 152218792Snp void* first() const { return next_free(first_block()); } 153218792Snp // returns the next block given a block p or NULL 154218792Snp void* next(void* p) const { return next_free(next_block(block_start(p))); } 155218792Snp 156218792Snp // Statistics 157248925Snp size_t capacity() const; 158218792Snp size_t max_capacity() const; 159237263Snp size_t allocated_capacity() const; 160237263Snp size_t unallocated_capacity() const { return max_capacity() - allocated_capacity(); } 161237263Snp 162237263Snpprivate: 163255006Snp size_t heap_unallocated_capacity() const; 164228561Snp 165237263Snppublic: 166255006Snp // Debugging 167228561Snp void verify(); 168228561Snp void print() PRODUCT_RETURN; 169218792Snp}; 170218792Snp 171228561Snp#endif // SHARE_VM_MEMORY_HEAP_HPP 172248925Snp