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src/share/vm/runtime/virtualspace.hpp@1fdb98a17101 (annotated)

src/share/vm/runtime/virtualspace.hpp

Sat, 19 Jul 2008 17:38:22 -0400

author

coleenp

date

Sat, 19 Jul 2008 17:38:22 -0400

changeset 672

1fdb98a17101

parent 435

a61af66fc99e

child 772

9ee9cf798b59

permissions

-rw-r--r--

6716785: implicit null checks not triggering with CompressedOops
Summary: allocate alignment-sized page(s) below java heap so that memory accesses at heap_base+1page give signal and cause an implicit null check
Reviewed-by: kvn, jmasa, phh, jcoomes

duke@435	1	/*
duke@435	2	* Copyright 1997-2005 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	// ReservedSpace is a data structure for reserving a contiguous address range.
duke@435	26
duke@435	27	class ReservedSpace VALUE_OBJ_CLASS_SPEC {
duke@435	28	friend class VMStructs;
duke@435	29	private:
duke@435	30	char* _base;
duke@435	31	size_t _size;
coleenp@672	32	size_t _noaccess_prefix;
duke@435	33	size_t _alignment;
duke@435	34	bool _special;
duke@435	35
duke@435	36	// ReservedSpace
duke@435	37	ReservedSpace(char* base, size_t size, size_t alignment, bool special);
duke@435	38	void initialize(size_t size, size_t alignment, bool large,
coleenp@672	39	char* requested_address,
coleenp@672	40	const size_t noaccess_prefix);
duke@435	41
duke@435	42	// Release parts of an already-reserved memory region [addr, addr + len) to
duke@435	43	// get a new region that has "compound alignment." Return the start of the
duke@435	44	// resulting region, or NULL on failure.
duke@435	45	//
duke@435	46	// The region is logically divided into a prefix and a suffix. The prefix
duke@435	47	// starts at the result address, which is aligned to prefix_align. The suffix
duke@435	48	// starts at result address + prefix_size, which is aligned to suffix_align.
duke@435	49	// The total size of the result region is size prefix_size + suffix_size.
duke@435	50	char* align_reserved_region(char* addr, const size_t len,
duke@435	51	const size_t prefix_size,
duke@435	52	const size_t prefix_align,
duke@435	53	const size_t suffix_size,
duke@435	54	const size_t suffix_align);
duke@435	55
duke@435	56	// Reserve memory, call align_reserved_region() to alignment it and return the
duke@435	57	// result.
duke@435	58	char* reserve_and_align(const size_t reserve_size,
duke@435	59	const size_t prefix_size,
duke@435	60	const size_t prefix_align,
duke@435	61	const size_t suffix_size,
duke@435	62	const size_t suffix_align);
duke@435	63
coleenp@672	64	protected:
coleenp@672	65	// Create protection page at the beginning of the space.
coleenp@672	66	void protect_noaccess_prefix(const size_t size);
coleenp@672	67
duke@435	68	public:
duke@435	69	// Constructor
duke@435	70	ReservedSpace(size_t size);
duke@435	71	ReservedSpace(size_t size, size_t alignment, bool large,
coleenp@672	72	char* requested_address = NULL,
coleenp@672	73	const size_t noaccess_prefix = 0);
duke@435	74	ReservedSpace(const size_t prefix_size, const size_t prefix_align,
coleenp@672	75	const size_t suffix_size, const size_t suffix_align,
coleenp@672	76	const size_t noaccess_prefix);
duke@435	77
duke@435	78	// Accessors
duke@435	79	char* base() const { return _base; }
duke@435	80	size_t size() const { return _size; }
duke@435	81	size_t alignment() const { return _alignment; }
duke@435	82	bool special() const { return _special; }
duke@435	83
coleenp@672	84	size_t noaccess_prefix() const { return _noaccess_prefix; }
coleenp@672	85
duke@435	86	bool is_reserved() const { return _base != NULL; }
duke@435	87	void release();
duke@435	88
duke@435	89	// Splitting
duke@435	90	ReservedSpace first_part(size_t partition_size, size_t alignment,
duke@435	91	bool split = false, bool realloc = true);
duke@435	92	ReservedSpace last_part (size_t partition_size, size_t alignment);
duke@435	93
duke@435	94	// These simply call the above using the default alignment.
duke@435	95	inline ReservedSpace first_part(size_t partition_size,
duke@435	96	bool split = false, bool realloc = true);
duke@435	97	inline ReservedSpace last_part (size_t partition_size);
duke@435	98
duke@435	99	// Alignment
duke@435	100	static size_t page_align_size_up(size_t size);
duke@435	101	static size_t page_align_size_down(size_t size);
duke@435	102	static size_t allocation_align_size_up(size_t size);
duke@435	103	static size_t allocation_align_size_down(size_t size);
duke@435	104	};
duke@435	105
duke@435	106	ReservedSpace
duke@435	107	ReservedSpace::first_part(size_t partition_size, bool split, bool realloc)
duke@435	108	{
duke@435	109	return first_part(partition_size, alignment(), split, realloc);
duke@435	110	}
duke@435	111
duke@435	112	ReservedSpace ReservedSpace::last_part(size_t partition_size)
duke@435	113	{
duke@435	114	return last_part(partition_size, alignment());
duke@435	115	}
duke@435	116
coleenp@672	117	// Class encapsulating behavior specific of memory space reserved for Java heap
coleenp@672	118	class ReservedHeapSpace : public ReservedSpace {
coleenp@672	119	public:
coleenp@672	120	// Constructor
coleenp@672	121	ReservedHeapSpace(size_t size, size_t forced_base_alignment,
coleenp@672	122	bool large, char* requested_address);
coleenp@672	123	ReservedHeapSpace(const size_t prefix_size, const size_t prefix_align,
coleenp@672	124	const size_t suffix_size, const size_t suffix_align);
coleenp@672	125	};
coleenp@672	126
duke@435	127	// VirtualSpace is data structure for committing a previously reserved address range in smaller chunks.
duke@435	128
duke@435	129	class VirtualSpace VALUE_OBJ_CLASS_SPEC {
duke@435	130	friend class VMStructs;
duke@435	131	private:
duke@435	132	// Reserved area
duke@435	133	char* _low_boundary;
duke@435	134	char* _high_boundary;
duke@435	135
duke@435	136	// Committed area
duke@435	137	char* _low;
duke@435	138	char* _high;
duke@435	139
duke@435	140	// The entire space has been committed and pinned in memory, no
duke@435	141	// os::commit_memory() or os::uncommit_memory().
duke@435	142	bool _special;
duke@435	143
duke@435	144	// MPSS Support
duke@435	145	// Each virtualspace region has a lower, middle, and upper region.
duke@435	146	// Each region has an end boundary and a high pointer which is the
duke@435	147	// high water mark for the last allocated byte.
duke@435	148	// The lower and upper unaligned to LargePageSizeInBytes uses default page.
duke@435	149	// size. The middle region uses large page size.
duke@435	150	char* _lower_high;
duke@435	151	char* _middle_high;
duke@435	152	char* _upper_high;
duke@435	153
duke@435	154	char* _lower_high_boundary;
duke@435	155	char* _middle_high_boundary;
duke@435	156	char* _upper_high_boundary;
duke@435	157
duke@435	158	size_t _lower_alignment;
duke@435	159	size_t _middle_alignment;
duke@435	160	size_t _upper_alignment;
duke@435	161
duke@435	162	// MPSS Accessors
duke@435	163	char* lower_high() const { return _lower_high; }
duke@435	164	char* middle_high() const { return _middle_high; }
duke@435	165	char* upper_high() const { return _upper_high; }
duke@435	166
duke@435	167	char* lower_high_boundary() const { return _lower_high_boundary; }
duke@435	168	char* middle_high_boundary() const { return _middle_high_boundary; }
duke@435	169	char* upper_high_boundary() const { return _upper_high_boundary; }
duke@435	170
duke@435	171	size_t lower_alignment() const { return _lower_alignment; }
duke@435	172	size_t middle_alignment() const { return _middle_alignment; }
duke@435	173	size_t upper_alignment() const { return _upper_alignment; }
duke@435	174
duke@435	175	public:
duke@435	176	// Committed area
duke@435	177	char* low() const { return _low; }
duke@435	178	char* high() const { return _high; }
duke@435	179
duke@435	180	// Reserved area
duke@435	181	char* low_boundary() const { return _low_boundary; }
duke@435	182	char* high_boundary() const { return _high_boundary; }
duke@435	183
duke@435	184	bool special() const { return _special; }
duke@435	185
duke@435	186	public:
duke@435	187	// Initialization
duke@435	188	VirtualSpace();
duke@435	189	bool initialize(ReservedSpace rs, size_t committed_byte_size);
duke@435	190
duke@435	191	// Destruction
duke@435	192	~VirtualSpace();
duke@435	193
duke@435	194	// Testers (all sizes are byte sizes)
duke@435	195	size_t committed_size() const;
duke@435	196	size_t reserved_size() const;
duke@435	197	size_t uncommitted_size() const;
duke@435	198	bool contains(const void* p) const;
duke@435	199
duke@435	200	// Operations
duke@435	201	// returns true on success, false otherwise
duke@435	202	bool expand_by(size_t bytes, bool pre_touch = false);
duke@435	203	void shrink_by(size_t bytes);
duke@435	204	void release();
duke@435	205
duke@435	206	void check_for_contiguity() PRODUCT_RETURN;
duke@435	207
duke@435	208	// Debugging
duke@435	209	void print() PRODUCT_RETURN;
duke@435	210	};