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src/share/vm/memory/filemap.hpp@0bfd3fb24150 (annotated)

src/share/vm/memory/filemap.hpp

Tue, 13 Apr 2010 13:52:10 -0700

author

jmasa

date

Tue, 13 Apr 2010 13:52:10 -0700

changeset 1822

0bfd3fb24150

parent 435

a61af66fc99e

child 1907

c18cbe5936b8

permissions

-rw-r--r--

6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
Summary: Ensure a full GC that clears SoftReferences before throwing an out-of-memory
Reviewed-by: ysr, jcoomes

duke@435	1	/*
duke@435	2	* Copyright 2003-2006 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	// Layout of the file:
duke@435	26	// header: dump of archive instance plus versioning info, datestamp, etc.
duke@435	27	// [magic # = 0xF00BABA2]
duke@435	28	// ... padding to align on page-boundary
duke@435	29	// read-write space from CompactingPermGenGen
duke@435	30	// read-only space from CompactingPermGenGen
duke@435	31	// misc data (block offset table, string table, symbols, dictionary, etc.)
duke@435	32	// tag(666)
duke@435	33
duke@435	34	static const int JVM_SHARED_JARS_MAX = 128;
duke@435	35	static const int JVM_SPACENAME_MAX = 128;
duke@435	36	static const int JVM_IDENT_MAX = 256;
duke@435	37	static const int JVM_ARCH_MAX = 12;
duke@435	38
duke@435	39
duke@435	40
duke@435	41	class FileMapInfo : public CHeapObj {
duke@435	42	private:
duke@435	43	enum {
duke@435	44	_invalid_version = -1,
duke@435	45	_current_version = 1
duke@435	46	};
duke@435	47
duke@435	48	bool _file_open;
duke@435	49	int _fd;
duke@435	50	long _file_offset;
duke@435	51
duke@435	52	// FileMapHeader describes the shared space data in the file to be
duke@435	53	// mapped. This structure gets written to a file. It is not a class, so
duke@435	54	// that the compilers don't add any compiler-private data to it.
duke@435	55
duke@435	56	struct FileMapHeader {
duke@435	57	int _magic; // identify file type.
duke@435	58	int _version; // (from enum, above.)
duke@435	59	size_t _alignment; // how shared archive should be aligned
duke@435	60
duke@435	61	struct space_info {
duke@435	62	int _file_offset; // sizeof(this) rounded to vm page size
duke@435	63	char* _base; // copy-on-write base address
duke@435	64	size_t _capacity; // for validity checking
duke@435	65	size_t _used; // for setting space top on read
duke@435	66	bool _read_only; // read only space?
duke@435	67	bool _allow_exec; // executable code in space?
duke@435	68	} _space[CompactingPermGenGen::n_regions];
duke@435	69
duke@435	70	// The following fields are all sanity checks for whether this archive
duke@435	71	// will function correctly with this JVM and the bootclasspath it's
duke@435	72	// invoked with.
duke@435	73	char _arch[JVM_ARCH_MAX]; // architecture
duke@435	74	char _jvm_ident[JVM_IDENT_MAX]; // identifier for jvm
duke@435	75	int _num_jars; // Number of jars in bootclasspath
duke@435	76
duke@435	77	// Per jar file data: timestamp, size.
duke@435	78
duke@435	79	struct {
duke@435	80	time_t _timestamp; // jar timestamp.
duke@435	81	long _filesize; // jar file size.
duke@435	82	} _jar[JVM_SHARED_JARS_MAX];
duke@435	83	} _header;
duke@435	84	const char* _full_path;
duke@435	85
duke@435	86	static FileMapInfo* _current_info;
duke@435	87
duke@435	88	bool init_from_file(int fd);
duke@435	89	void align_file_position();
duke@435	90
duke@435	91	public:
duke@435	92	FileMapInfo() {
duke@435	93	_file_offset = 0;
duke@435	94	_file_open = false;
duke@435	95	_header._version = _invalid_version;
duke@435	96	}
duke@435	97
duke@435	98	static int current_version() { return _current_version; }
duke@435	99	void populate_header(size_t alignment);
duke@435	100	bool validate();
duke@435	101	void invalidate();
duke@435	102	int version() { return _header._version; }
duke@435	103	size_t alignment() { return _header._alignment; }
duke@435	104	size_t space_capacity(int i) { return _header._space[i]._capacity; }
duke@435	105	char* region_base(int i) { return _header._space[i]._base; }
duke@435	106	struct FileMapHeader* header() { return &_header; }
duke@435	107
duke@435	108	static void set_current_info(FileMapInfo* info) { _current_info = info; }
duke@435	109	static FileMapInfo* current_info() { return _current_info; }
duke@435	110	static void assert_mark(bool check);
duke@435	111
duke@435	112	// File manipulation.
duke@435	113	bool initialize();
duke@435	114	bool open_for_read();
duke@435	115	void open_for_write();
duke@435	116	void write_header();
duke@435	117	void write_space(int i, CompactibleSpace* space, bool read_only);
duke@435	118	void write_region(int region, char* base, size_t size,
duke@435	119	size_t capacity, bool read_only, bool allow_exec);
duke@435	120	void write_bytes(const void* buffer, int count);
duke@435	121	void write_bytes_aligned(const void* buffer, int count);
duke@435	122	bool map_space(int i, ReservedSpace rs, ContiguousSpace *space);
duke@435	123	char* map_region(int i, ReservedSpace rs);
duke@435	124	char* map_region(int i, bool address_must_match);
duke@435	125	void unmap_region(int i);
duke@435	126	void close();
duke@435	127	bool is_open() { return _file_open; }
duke@435	128
duke@435	129	// JVM/TI RedefineClasses() support:
duke@435	130	// Remap the shared readonly space to shared readwrite, private.
duke@435	131	bool remap_shared_readonly_as_readwrite();
duke@435	132
duke@435	133	// Errors.
duke@435	134	static void fail_stop(const char *msg, ...);
duke@435	135	void fail_continue(const char *msg, ...);
duke@435	136
duke@435	137	// Return true if given address is in the mapped shared space.
duke@435	138	bool is_in_shared_space(const void* p);
duke@435	139	};