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

src/share/vm/memory/heap.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

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation.
aoqi@0	8	*
aoqi@0	9	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	12	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	13	* accompanied this code).
aoqi@0	14	*
aoqi@0	15	* You should have received a copy of the GNU General Public License version
aoqi@0	16	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	18	*
aoqi@0	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	20	* or visit www.oracle.com if you need additional information or have any
aoqi@0	21	* questions.
aoqi@0	22	*
aoqi@0	23	*/
aoqi@0	24
aoqi@0	25	#ifndef SHARE_VM_MEMORY_HEAP_HPP
aoqi@0	26	#define SHARE_VM_MEMORY_HEAP_HPP
aoqi@0	27
aoqi@0	28	#include "memory/allocation.hpp"
aoqi@0	29	#include "runtime/virtualspace.hpp"
aoqi@0	30
aoqi@0	31	// Blocks
aoqi@0	32
aoqi@0	33	class HeapBlock VALUE_OBJ_CLASS_SPEC {
aoqi@0	34	friend class VMStructs;
aoqi@0	35
aoqi@0	36	public:
aoqi@0	37	struct Header {
aoqi@0	38	size_t _length; // the length in segments
aoqi@0	39	bool _used; // Used bit
aoqi@0	40	};
aoqi@0	41
aoqi@0	42	protected:
aoqi@0	43	union {
aoqi@0	44	Header _header;
aoqi@0	45	int64_t _padding[ (sizeof(Header) + sizeof(int64_t)-1) / sizeof(int64_t) ];
aoqi@0	46	// pad to 0 mod 8
aoqi@0	47	};
aoqi@0	48
aoqi@0	49	public:
aoqi@0	50	// Initialization
aoqi@0	51	void initialize(size_t length) { _header._length = length; set_used(); }
aoqi@0	52
aoqi@0	53	// Accessors
aoqi@0	54	void* allocated_space() const { return (void*)(this + 1); }
aoqi@0	55	size_t length() const { return _header._length; }
aoqi@0	56
aoqi@0	57	// Used/free
aoqi@0	58	void set_used() { _header._used = true; }
aoqi@0	59	void set_free() { _header._used = false; }
aoqi@0	60	bool free() { return !_header._used; }
aoqi@0	61	};
aoqi@0	62
aoqi@0	63	class FreeBlock: public HeapBlock {
aoqi@0	64	friend class VMStructs;
aoqi@0	65	protected:
aoqi@0	66	FreeBlock* _link;
aoqi@0	67
aoqi@0	68	public:
aoqi@0	69	// Initialization
aoqi@0	70	void initialize(size_t length) { HeapBlock::initialize(length); _link= NULL; }
aoqi@0	71
aoqi@0	72	// Merging
aoqi@0	73	void set_length(size_t l) { _header._length = l; }
aoqi@0	74
aoqi@0	75	// Accessors
aoqi@0	76	FreeBlock* link() const { return _link; }
aoqi@0	77	void set_link(FreeBlock* link) { _link = link; }
aoqi@0	78	};
aoqi@0	79
aoqi@0	80	class CodeHeap : public CHeapObj<mtCode> {
aoqi@0	81	friend class VMStructs;
aoqi@0	82	private:
aoqi@0	83	VirtualSpace _memory; // the memory holding the blocks
aoqi@0	84	VirtualSpace _segmap; // the memory holding the segment map
aoqi@0	85
aoqi@0	86	size_t _number_of_committed_segments;
aoqi@0	87	size_t _number_of_reserved_segments;
aoqi@0	88	size_t _segment_size;
aoqi@0	89	int _log2_segment_size;
aoqi@0	90
aoqi@0	91	size_t _next_segment;
aoqi@0	92
aoqi@0	93	FreeBlock* _freelist;
aoqi@0	94	size_t _freelist_segments; // No. of segments in freelist
aoqi@0	95
aoqi@0	96	// Helper functions
aoqi@0	97	size_t size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }
aoqi@0	98	size_t segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }
aoqi@0	99
aoqi@0	100	size_t segment_for(void* p) const { return ((char*)p - _memory.low()) >> _log2_segment_size; }
aoqi@0	101	HeapBlock* block_at(size_t i) const { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }
aoqi@0	102
aoqi@0	103	void mark_segmap_as_free(size_t beg, size_t end);
aoqi@0	104	void mark_segmap_as_used(size_t beg, size_t end);
aoqi@0	105
aoqi@0	106	// Freelist management helpers
aoqi@0	107	FreeBlock* following_block(FreeBlock *b);
aoqi@0	108	void insert_after(FreeBlock* a, FreeBlock* b);
aoqi@0	109	void merge_right (FreeBlock* a);
aoqi@0	110
aoqi@0	111	// Toplevel freelist management
aoqi@0	112	void add_to_freelist(HeapBlock *b);
aoqi@0	113	FreeBlock* search_freelist(size_t length, bool is_critical);
aoqi@0	114
aoqi@0	115	// Iteration helpers
aoqi@0	116	void* next_free(HeapBlock* b) const;
aoqi@0	117	HeapBlock* first_block() const;
aoqi@0	118	HeapBlock* next_block(HeapBlock* b) const;
aoqi@0	119	HeapBlock* block_start(void* p) const;
aoqi@0	120
aoqi@0	121	// to perform additional actions on creation of executable code
aoqi@0	122	void on_code_mapping(char* base, size_t size);
aoqi@0	123
aoqi@0	124	public:
aoqi@0	125	CodeHeap();
aoqi@0	126
aoqi@0	127	// Heap extents
aoqi@0	128	bool reserve(size_t reserved_size, size_t committed_size, size_t segment_size);
aoqi@0	129	void release(); // releases all allocated memory
aoqi@0	130	bool expand_by(size_t size); // expands commited memory by size
aoqi@0	131	void shrink_by(size_t size); // shrinks commited memory by size
aoqi@0	132	void clear(); // clears all heap contents
aoqi@0	133
aoqi@0	134	// Memory allocation
aoqi@0	135	void* allocate (size_t size, bool is_critical); // allocates a block of size or returns NULL
aoqi@0	136	void deallocate(void* p); // deallocates a block
aoqi@0	137
aoqi@0	138	// Attributes
aoqi@0	139	char* low_boundary() const { return _memory.low_boundary (); }
aoqi@0	140	char* high() const { return _memory.high(); }
aoqi@0	141	char* high_boundary() const { return _memory.high_boundary(); }
aoqi@0	142
aoqi@0	143	bool contains(const void* p) const { return low_boundary() <= p && p < high(); }
aoqi@0	144	void* find_start(void* p) const; // returns the block containing p or NULL
aoqi@0	145	size_t alignment_unit() const; // alignment of any block
aoqi@0	146	size_t alignment_offset() const; // offset of first byte of any block, within the enclosing alignment unit
aoqi@0	147	static size_t header_size(); // returns the header size for each heap block
aoqi@0	148
aoqi@0	149	// Iteration
aoqi@0	150
aoqi@0	151	// returns the first block or NULL
aoqi@0	152	void* first() const { return next_free(first_block()); }
aoqi@0	153	// returns the next block given a block p or NULL
aoqi@0	154	void* next(void* p) const { return next_free(next_block(block_start(p))); }
aoqi@0	155
aoqi@0	156	// Statistics
aoqi@0	157	size_t capacity() const;
aoqi@0	158	size_t max_capacity() const;
aoqi@0	159	size_t allocated_capacity() const;
aoqi@0	160	size_t unallocated_capacity() const { return max_capacity() - allocated_capacity(); }
aoqi@0	161
aoqi@0	162	private:
aoqi@0	163	size_t heap_unallocated_capacity() const;
aoqi@0	164
aoqi@0	165	public:
aoqi@0	166	// Debugging
aoqi@0	167	void verify();
aoqi@0	168	void print() PRODUCT_RETURN;
aoqi@0	169	};
aoqi@0	170
aoqi@0	171	#endif // SHARE_VM_MEMORY_HEAP_HPP