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src/share/vm/memory/space.hpp@8ce625481709 (annotated)

src/share/vm/memory/space.hpp

Fri, 15 Apr 2011 09:36:28 -0400

author

coleenp

date

Fri, 15 Apr 2011 09:36:28 -0400

changeset 2777

8ce625481709

parent 2314

f95d63e2154a

child 3156

f08d439fab8c

permissions

-rw-r--r--

7032407: Crash in LinkResolver::runtime_resolve_virtual_method()
Summary: Make CDS reorder vtables so that dump time vtables match run time order, so when redefine classes reinitializes them, they aren't in the wrong order.
Reviewed-by: dcubed, acorn

duke@435	1	/*
stefank@2314	2	* Copyright (c) 1997, 2010, Oracle and/or its affiliates. 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	*
trims@1907	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907	20	* or visit www.oracle.com if you need additional information or have any
trims@1907	21	* questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
stefank@2314	25	#ifndef SHARE_VM_MEMORY_SPACE_HPP
stefank@2314	26	#define SHARE_VM_MEMORY_SPACE_HPP
stefank@2314	27
stefank@2314	28	#include "memory/allocation.hpp"
stefank@2314	29	#include "memory/blockOffsetTable.hpp"
stefank@2314	30	#include "memory/cardTableModRefBS.hpp"
stefank@2314	31	#include "memory/iterator.hpp"
stefank@2314	32	#include "memory/memRegion.hpp"
stefank@2314	33	#include "memory/watermark.hpp"
stefank@2314	34	#include "oops/markOop.hpp"
stefank@2314	35	#include "runtime/mutexLocker.hpp"
stefank@2314	36	#include "runtime/prefetch.hpp"
stefank@2314	37	#include "utilities/workgroup.hpp"
stefank@2314	38	#ifdef TARGET_OS_FAMILY_linux
stefank@2314	39	# include "os_linux.inline.hpp"
stefank@2314	40	#endif
stefank@2314	41	#ifdef TARGET_OS_FAMILY_solaris
stefank@2314	42	# include "os_solaris.inline.hpp"
stefank@2314	43	#endif
stefank@2314	44	#ifdef TARGET_OS_FAMILY_windows
stefank@2314	45	# include "os_windows.inline.hpp"
stefank@2314	46	#endif
stefank@2314	47
duke@435	48	// A space is an abstraction for the "storage units" backing
duke@435	49	// up the generation abstraction. It includes specific
duke@435	50	// implementations for keeping track of free and used space,
duke@435	51	// for iterating over objects and free blocks, etc.
duke@435	52
duke@435	53	// Here's the Space hierarchy:
duke@435	54	//
duke@435	55	// - Space -- an asbtract base class describing a heap area
duke@435	56	// - CompactibleSpace -- a space supporting compaction
duke@435	57	// - CompactibleFreeListSpace -- (used for CMS generation)
duke@435	58	// - ContiguousSpace -- a compactible space in which all free space
duke@435	59	// is contiguous
duke@435	60	// - EdenSpace -- contiguous space used as nursery
duke@435	61	// - ConcEdenSpace -- contiguous space with a 'soft end safe' allocation
duke@435	62	// - OffsetTableContigSpace -- contiguous space with a block offset array
duke@435	63	// that allows "fast" block_start calls
duke@435	64	// - TenuredSpace -- (used for TenuredGeneration)
duke@435	65	// - ContigPermSpace -- an offset table contiguous space for perm gen
duke@435	66
duke@435	67	// Forward decls.
duke@435	68	class Space;
duke@435	69	class BlockOffsetArray;
duke@435	70	class BlockOffsetArrayContigSpace;
duke@435	71	class Generation;
duke@435	72	class CompactibleSpace;
duke@435	73	class BlockOffsetTable;
duke@435	74	class GenRemSet;
duke@435	75	class CardTableRS;
duke@435	76	class DirtyCardToOopClosure;
duke@435	77
duke@435	78	// An oop closure that is circumscribed by a filtering memory region.
coleenp@548	79	class SpaceMemRegionOopsIterClosure: public OopClosure {
coleenp@548	80	private:
coleenp@548	81	OopClosure* _cl;
coleenp@548	82	MemRegion _mr;
coleenp@548	83	protected:
coleenp@548	84	template <class T> void do_oop_work(T* p) {
coleenp@548	85	if (_mr.contains(p)) {
coleenp@548	86	_cl->do_oop(p);
duke@435	87	}
duke@435	88	}
coleenp@548	89	public:
coleenp@548	90	SpaceMemRegionOopsIterClosure(OopClosure* cl, MemRegion mr):
coleenp@548	91	_cl(cl), _mr(mr) {}
coleenp@548	92	virtual void do_oop(oop* p);
coleenp@548	93	virtual void do_oop(narrowOop* p);
duke@435	94	};
duke@435	95
duke@435	96	// A Space describes a heap area. Class Space is an abstract
duke@435	97	// base class.
duke@435	98	//
duke@435	99	// Space supports allocation, size computation and GC support is provided.
duke@435	100	//
duke@435	101	// Invariant: bottom() and end() are on page_size boundaries and
duke@435	102	// bottom() <= top() <= end()
duke@435	103	// top() is inclusive and end() is exclusive.
duke@435	104
duke@435	105	class Space: public CHeapObj {
duke@435	106	friend class VMStructs;
duke@435	107	protected:
duke@435	108	HeapWord* _bottom;
duke@435	109	HeapWord* _end;
duke@435	110
duke@435	111	// Used in support of save_marks()
duke@435	112	HeapWord* _saved_mark_word;
duke@435	113
duke@435	114	MemRegionClosure* _preconsumptionDirtyCardClosure;
duke@435	115
duke@435	116	// A sequential tasks done structure. This supports
duke@435	117	// parallel GC, where we have threads dynamically
duke@435	118	// claiming sub-tasks from a larger parallel task.
duke@435	119	SequentialSubTasksDone _par_seq_tasks;
duke@435	120
duke@435	121	Space():
duke@435	122	_bottom(NULL), _end(NULL), _preconsumptionDirtyCardClosure(NULL) { }
duke@435	123
duke@435	124	public:
duke@435	125	// Accessors
duke@435	126	HeapWord* bottom() const { return _bottom; }
duke@435	127	HeapWord* end() const { return _end; }
duke@435	128	virtual void set_bottom(HeapWord* value) { _bottom = value; }
duke@435	129	virtual void set_end(HeapWord* value) { _end = value; }
duke@435	130
ysr@777	131	virtual HeapWord* saved_mark_word() const { return _saved_mark_word; }
ysr@1280	132
duke@435	133	void set_saved_mark_word(HeapWord* p) { _saved_mark_word = p; }
duke@435	134
duke@435	135	MemRegionClosure* preconsumptionDirtyCardClosure() const {
duke@435	136	return _preconsumptionDirtyCardClosure;
duke@435	137	}
duke@435	138	void setPreconsumptionDirtyCardClosure(MemRegionClosure* cl) {
duke@435	139	_preconsumptionDirtyCardClosure = cl;
duke@435	140	}
duke@435	141
duke@435	142	// Returns a subregion of the space containing all the objects in
duke@435	143	// the space.
duke@435	144	virtual MemRegion used_region() const { return MemRegion(bottom(), end()); }
duke@435	145
duke@435	146	// Returns a region that is guaranteed to contain (at least) all objects
duke@435	147	// allocated at the time of the last call to "save_marks". If the space
duke@435	148	// initializes its DirtyCardToOopClosure's specifying the "contig" option
duke@435	149	// (that is, if the space is contiguous), then this region must contain only
duke@435	150	// such objects: the memregion will be from the bottom of the region to the
duke@435	151	// saved mark. Otherwise, the "obj_allocated_since_save_marks" method of
duke@435	152	// the space must distiguish between objects in the region allocated before
duke@435	153	// and after the call to save marks.
duke@435	154	virtual MemRegion used_region_at_save_marks() const {
duke@435	155	return MemRegion(bottom(), saved_mark_word());
duke@435	156	}
duke@435	157
ysr@777	158	// Initialization.
ysr@777	159	// "initialize" should be called once on a space, before it is used for
ysr@777	160	// any purpose. The "mr" arguments gives the bounds of the space, and
ysr@777	161	// the "clear_space" argument should be true unless the memory in "mr" is
ysr@777	162	// known to be zeroed.
jmasa@698	163	virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
ysr@777	164
ysr@777	165	// The "clear" method must be called on a region that may have
ysr@777	166	// had allocation performed in it, but is now to be considered empty.
jmasa@698	167	virtual void clear(bool mangle_space);
duke@435	168
duke@435	169	// For detecting GC bugs. Should only be called at GC boundaries, since
duke@435	170	// some unused space may be used as scratch space during GC's.
duke@435	171	// Default implementation does nothing. We also call this when expanding
duke@435	172	// a space to satisfy an allocation request. See bug #4668531
duke@435	173	virtual void mangle_unused_area() {}
jmasa@698	174	virtual void mangle_unused_area_complete() {}
duke@435	175	virtual void mangle_region(MemRegion mr) {}
duke@435	176
duke@435	177	// Testers
duke@435	178	bool is_empty() const { return used() == 0; }
duke@435	179	bool not_empty() const { return used() > 0; }
duke@435	180
duke@435	181	// Returns true iff the given the space contains the
duke@435	182	// given address as part of an allocated object. For
duke@435	183	// ceratin kinds of spaces, this might be a potentially
duke@435	184	// expensive operation. To prevent performance problems
duke@435	185	// on account of its inadvertent use in product jvm's,
duke@435	186	// we restrict its use to assertion checks only.
duke@435	187	virtual bool is_in(const void* p) const;
duke@435	188
duke@435	189	// Returns true iff the given reserved memory of the space contains the
duke@435	190	// given address.
duke@435	191	bool is_in_reserved(const void* p) const { return _bottom <= p && p < _end; }
duke@435	192
duke@435	193	// Returns true iff the given block is not allocated.
duke@435	194	virtual bool is_free_block(const HeapWord* p) const = 0;
duke@435	195
duke@435	196	// Test whether p is double-aligned
duke@435	197	static bool is_aligned(void* p) {
duke@435	198	return ((intptr_t)p & (sizeof(double)-1)) == 0;
duke@435	199	}
duke@435	200
duke@435	201	// Size computations. Sizes are in bytes.
duke@435	202	size_t capacity() const { return byte_size(bottom(), end()); }
duke@435	203	virtual size_t used() const = 0;
duke@435	204	virtual size_t free() const = 0;
duke@435	205
duke@435	206	// Iterate over all the ref-containing fields of all objects in the
duke@435	207	// space, calling "cl.do_oop" on each. Fields in objects allocated by
duke@435	208	// applications of the closure are not included in the iteration.
duke@435	209	virtual void oop_iterate(OopClosure* cl);
duke@435	210
duke@435	211	// Same as above, restricted to the intersection of a memory region and
duke@435	212	// the space. Fields in objects allocated by applications of the closure
duke@435	213	// are not included in the iteration.
duke@435	214	virtual void oop_iterate(MemRegion mr, OopClosure* cl) = 0;
duke@435	215
duke@435	216	// Iterate over all objects in the space, calling "cl.do_object" on
duke@435	217	// each. Objects allocated by applications of the closure are not
duke@435	218	// included in the iteration.
duke@435	219	virtual void object_iterate(ObjectClosure* blk) = 0;
jmasa@952	220	// Similar to object_iterate() except only iterates over
jmasa@952	221	// objects whose internal references point to objects in the space.
jmasa@952	222	virtual void safe_object_iterate(ObjectClosure* blk) = 0;
duke@435	223
duke@435	224	// Iterate over all objects that intersect with mr, calling "cl->do_object"
duke@435	225	// on each. There is an exception to this: if this closure has already
duke@435	226	// been invoked on an object, it may skip such objects in some cases. This is
duke@435	227	// Most likely to happen in an "upwards" (ascending address) iteration of
duke@435	228	// MemRegions.
duke@435	229	virtual void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl);
duke@435	230
duke@435	231	// Iterate over as many initialized objects in the space as possible,
duke@435	232	// calling "cl.do_object_careful" on each. Return NULL if all objects
duke@435	233	// in the space (at the start of the iteration) were iterated over.
duke@435	234	// Return an address indicating the extent of the iteration in the
duke@435	235	// event that the iteration had to return because of finding an
duke@435	236	// uninitialized object in the space, or if the closure "cl"
duke@435	237	// signalled early termination.
duke@435	238	virtual HeapWord* object_iterate_careful(ObjectClosureCareful* cl);
duke@435	239	virtual HeapWord* object_iterate_careful_m(MemRegion mr,
duke@435	240	ObjectClosureCareful* cl);
duke@435	241
duke@435	242	// Create and return a new dirty card to oop closure. Can be
duke@435	243	// overriden to return the appropriate type of closure
duke@435	244	// depending on the type of space in which the closure will
duke@435	245	// operate. ResourceArea allocated.
duke@435	246	virtual DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl,
duke@435	247	CardTableModRefBS::PrecisionStyle precision,
duke@435	248	HeapWord* boundary = NULL);
duke@435	249
duke@435	250	// If "p" is in the space, returns the address of the start of the
duke@435	251	// "block" that contains "p". We say "block" instead of "object" since
duke@435	252	// some heaps may not pack objects densely; a chunk may either be an
duke@435	253	// object or a non-object. If "p" is not in the space, return NULL.
ysr@777	254	virtual HeapWord* block_start_const(const void* p) const = 0;
ysr@777	255
ysr@777	256	// The non-const version may have benevolent side effects on the data
ysr@777	257	// structure supporting these calls, possibly speeding up future calls.
ysr@777	258	// The default implementation, however, is simply to call the const
ysr@777	259	// version.
ysr@777	260	inline virtual HeapWord* block_start(const void* p);
duke@435	261
duke@435	262	// Requires "addr" to be the start of a chunk, and returns its size.
duke@435	263	// "addr + size" is required to be the start of a new chunk, or the end
duke@435	264	// of the active area of the heap.
duke@435	265	virtual size_t block_size(const HeapWord* addr) const = 0;
duke@435	266
duke@435	267	// Requires "addr" to be the start of a block, and returns "TRUE" iff
duke@435	268	// the block is an object.
duke@435	269	virtual bool block_is_obj(const HeapWord* addr) const = 0;
duke@435	270
duke@435	271	// Requires "addr" to be the start of a block, and returns "TRUE" iff
duke@435	272	// the block is an object and the object is alive.
duke@435	273	virtual bool obj_is_alive(const HeapWord* addr) const;
duke@435	274
duke@435	275	// Allocation (return NULL if full). Assumes the caller has established
duke@435	276	// mutually exclusive access to the space.
duke@435	277	virtual HeapWord* allocate(size_t word_size) = 0;
duke@435	278
duke@435	279	// Allocation (return NULL if full). Enforces mutual exclusion internally.
duke@435	280	virtual HeapWord* par_allocate(size_t word_size) = 0;
duke@435	281
duke@435	282	// Returns true if this object has been allocated since a
duke@435	283	// generation's "save_marks" call.
duke@435	284	virtual bool obj_allocated_since_save_marks(const oop obj) const = 0;
duke@435	285
duke@435	286	// Mark-sweep-compact support: all spaces can update pointers to objects
duke@435	287	// moving as a part of compaction.
duke@435	288	virtual void adjust_pointers();
duke@435	289
duke@435	290	// PrintHeapAtGC support
duke@435	291	virtual void print() const;
duke@435	292	virtual void print_on(outputStream* st) const;
duke@435	293	virtual void print_short() const;
duke@435	294	virtual void print_short_on(outputStream* st) const;
duke@435	295
duke@435	296
duke@435	297	// Accessor for parallel sequential tasks.
duke@435	298	SequentialSubTasksDone* par_seq_tasks() { return &_par_seq_tasks; }
duke@435	299
duke@435	300	// IF "this" is a ContiguousSpace, return it, else return NULL.
duke@435	301	virtual ContiguousSpace* toContiguousSpace() {
duke@435	302	return NULL;
duke@435	303	}
duke@435	304
duke@435	305	// Debugging
duke@435	306	virtual void verify(bool allow_dirty) const = 0;
duke@435	307	};
duke@435	308
duke@435	309	// A MemRegionClosure (ResourceObj) whose "do_MemRegion" function applies an
duke@435	310	// OopClosure to (the addresses of) all the ref-containing fields that could
duke@435	311	// be modified by virtue of the given MemRegion being dirty. (Note that
duke@435	312	// because of the imprecise nature of the write barrier, this may iterate
duke@435	313	// over oops beyond the region.)
duke@435	314	// This base type for dirty card to oop closures handles memory regions
duke@435	315	// in non-contiguous spaces with no boundaries, and should be sub-classed
duke@435	316	// to support other space types. See ContiguousDCTOC for a sub-class
duke@435	317	// that works with ContiguousSpaces.
duke@435	318
duke@435	319	class DirtyCardToOopClosure: public MemRegionClosureRO {
duke@435	320	protected:
duke@435	321	OopClosure* _cl;
duke@435	322	Space* _sp;
duke@435	323	CardTableModRefBS::PrecisionStyle _precision;
duke@435	324	HeapWord* _boundary; // If non-NULL, process only non-NULL oops
duke@435	325	// pointing below boundary.
ysr@777	326	HeapWord* _min_done; // ObjHeadPreciseArray precision requires
duke@435	327	// a downwards traversal; this is the
duke@435	328	// lowest location already done (or,
duke@435	329	// alternatively, the lowest address that
duke@435	330	// shouldn't be done again. NULL means infinity.)
duke@435	331	NOT_PRODUCT(HeapWord* _last_bottom;)
ysr@777	332	NOT_PRODUCT(HeapWord* _last_explicit_min_done;)
duke@435	333
duke@435	334	// Get the actual top of the area on which the closure will
duke@435	335	// operate, given where the top is assumed to be (the end of the
duke@435	336	// memory region passed to do_MemRegion) and where the object
duke@435	337	// at the top is assumed to start. For example, an object may
duke@435	338	// start at the top but actually extend past the assumed top,
duke@435	339	// in which case the top becomes the end of the object.
duke@435	340	virtual HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj);
duke@435	341
duke@435	342	// Walk the given memory region from bottom to (actual) top
duke@435	343	// looking for objects and applying the oop closure (_cl) to
duke@435	344	// them. The base implementation of this treats the area as
duke@435	345	// blocks, where a block may or may not be an object. Sub-
duke@435	346	// classes should override this to provide more accurate
duke@435	347	// or possibly more efficient walking.
duke@435	348	virtual void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top);
duke@435	349
duke@435	350	public:
duke@435	351	DirtyCardToOopClosure(Space* sp, OopClosure* cl,
duke@435	352	CardTableModRefBS::PrecisionStyle precision,
duke@435	353	HeapWord* boundary) :
duke@435	354	_sp(sp), _cl(cl), _precision(precision), _boundary(boundary),
duke@435	355	_min_done(NULL) {
ysr@777	356	NOT_PRODUCT(_last_bottom = NULL);
ysr@777	357	NOT_PRODUCT(_last_explicit_min_done = NULL);
duke@435	358	}
duke@435	359
duke@435	360	void do_MemRegion(MemRegion mr);
duke@435	361
duke@435	362	void set_min_done(HeapWord* min_done) {
duke@435	363	_min_done = min_done;
ysr@777	364	NOT_PRODUCT(_last_explicit_min_done = _min_done);
duke@435	365	}
duke@435	366	#ifndef PRODUCT
duke@435	367	void set_last_bottom(HeapWord* last_bottom) {
duke@435	368	_last_bottom = last_bottom;
duke@435	369	}
duke@435	370	#endif
duke@435	371	};
duke@435	372
duke@435	373	// A structure to represent a point at which objects are being copied
duke@435	374	// during compaction.
duke@435	375	class CompactPoint : public StackObj {
duke@435	376	public:
duke@435	377	Generation* gen;
duke@435	378	CompactibleSpace* space;
duke@435	379	HeapWord* threshold;
duke@435	380	CompactPoint(Generation* _gen, CompactibleSpace* _space,
duke@435	381	HeapWord* _threshold) :
duke@435	382	gen(_gen), space(_space), threshold(_threshold) {}
duke@435	383	};
duke@435	384
duke@435	385
duke@435	386	// A space that supports compaction operations. This is usually, but not
duke@435	387	// necessarily, a space that is normally contiguous. But, for example, a
duke@435	388	// free-list-based space whose normal collection is a mark-sweep without
duke@435	389	// compaction could still support compaction in full GC's.
duke@435	390
duke@435	391	class CompactibleSpace: public Space {
duke@435	392	friend class VMStructs;
duke@435	393	friend class CompactibleFreeListSpace;
duke@435	394	friend class CompactingPermGenGen;
duke@435	395	friend class CMSPermGenGen;
duke@435	396	private:
duke@435	397	HeapWord* _compaction_top;
duke@435	398	CompactibleSpace* _next_compaction_space;
duke@435	399
duke@435	400	public:
ysr@782	401	CompactibleSpace() :
ysr@782	402	_compaction_top(NULL), _next_compaction_space(NULL) {}
ysr@782	403
jmasa@698	404	virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
tonyp@791	405	virtual void clear(bool mangle_space);
duke@435	406
duke@435	407	// Used temporarily during a compaction phase to hold the value
duke@435	408	// top should have when compaction is complete.
duke@435	409	HeapWord* compaction_top() const { return _compaction_top; }
duke@435	410
duke@435	411	void set_compaction_top(HeapWord* value) {
duke@435	412	assert(value == NULL || (value >= bottom() && value <= end()),
duke@435	413	"should point inside space");
duke@435	414	_compaction_top = value;
duke@435	415	}
duke@435	416
duke@435	417	// Perform operations on the space needed after a compaction
duke@435	418	// has been performed.
duke@435	419	virtual void reset_after_compaction() {}
duke@435	420
duke@435	421	// Returns the next space (in the current generation) to be compacted in
duke@435	422	// the global compaction order. Also is used to select the next
duke@435	423	// space into which to compact.
duke@435	424
duke@435	425	virtual CompactibleSpace* next_compaction_space() const {
duke@435	426	return _next_compaction_space;
duke@435	427	}
duke@435	428
duke@435	429	void set_next_compaction_space(CompactibleSpace* csp) {
duke@435	430	_next_compaction_space = csp;
duke@435	431	}
duke@435	432
duke@435	433	// MarkSweep support phase2
duke@435	434
duke@435	435	// Start the process of compaction of the current space: compute
duke@435	436	// post-compaction addresses, and insert forwarding pointers. The fields
duke@435	437	// "cp->gen" and "cp->compaction_space" are the generation and space into
duke@435	438	// which we are currently compacting. This call updates "cp" as necessary,
duke@435	439	// and leaves the "compaction_top" of the final value of
duke@435	440	// "cp->compaction_space" up-to-date. Offset tables may be updated in
duke@435	441	// this phase as if the final copy had occurred; if so, "cp->threshold"
duke@435	442	// indicates when the next such action should be taken.
duke@435	443	virtual void prepare_for_compaction(CompactPoint* cp);
duke@435	444	// MarkSweep support phase3
duke@435	445	virtual void adjust_pointers();
duke@435	446	// MarkSweep support phase4
duke@435	447	virtual void compact();
duke@435	448
duke@435	449	// The maximum percentage of objects that can be dead in the compacted
duke@435	450	// live part of a compacted space ("deadwood" support.)
jcoomes@873	451	virtual size_t allowed_dead_ratio() const { return 0; };
duke@435	452
duke@435	453	// Some contiguous spaces may maintain some data structures that should
duke@435	454	// be updated whenever an allocation crosses a boundary. This function
duke@435	455	// returns the first such boundary.
duke@435	456	// (The default implementation returns the end of the space, so the
duke@435	457	// boundary is never crossed.)
duke@435	458	virtual HeapWord* initialize_threshold() { return end(); }
duke@435	459
duke@435	460	// "q" is an object of the given "size" that should be forwarded;
duke@435	461	// "cp" names the generation ("gen") and containing "this" (which must
duke@435	462	// also equal "cp->space"). "compact_top" is where in "this" the
duke@435	463	// next object should be forwarded to. If there is room in "this" for
duke@435	464	// the object, insert an appropriate forwarding pointer in "q".
duke@435	465	// If not, go to the next compaction space (there must
duke@435	466	// be one, since compaction must succeed -- we go to the first space of
duke@435	467	// the previous generation if necessary, updating "cp"), reset compact_top
duke@435	468	// and then forward. In either case, returns the new value of "compact_top".
duke@435	469	// If the forwarding crosses "cp->threshold", invokes the "cross_threhold"
duke@435	470	// function of the then-current compaction space, and updates "cp->threshold
duke@435	471	// accordingly".
duke@435	472	virtual HeapWord* forward(oop q, size_t size, CompactPoint* cp,
duke@435	473	HeapWord* compact_top);
duke@435	474
duke@435	475	// Return a size with adjusments as required of the space.
duke@435	476	virtual size_t adjust_object_size_v(size_t size) const { return size; }
duke@435	477
duke@435	478	protected:
duke@435	479	// Used during compaction.
duke@435	480	HeapWord* _first_dead;
duke@435	481	HeapWord* _end_of_live;
duke@435	482
duke@435	483	// Minimum size of a free block.
duke@435	484	virtual size_t minimum_free_block_size() const = 0;
duke@435	485
duke@435	486	// This the function is invoked when an allocation of an object covering
duke@435	487	// "start" to "end occurs crosses the threshold; returns the next
duke@435	488	// threshold. (The default implementation does nothing.)
duke@435	489	virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* the_end) {
duke@435	490	return end();
duke@435	491	}
duke@435	492
duke@435	493	// Requires "allowed_deadspace_words > 0", that "q" is the start of a
duke@435	494	// free block of the given "word_len", and that "q", were it an object,
duke@435	495	// would not move if forwared. If the size allows, fill the free
duke@435	496	// block with an object, to prevent excessive compaction. Returns "true"
duke@435	497	// iff the free region was made deadspace, and modifies
duke@435	498	// "allowed_deadspace_words" to reflect the number of available deadspace
duke@435	499	// words remaining after this operation.
duke@435	500	bool insert_deadspace(size_t& allowed_deadspace_words, HeapWord* q,
duke@435	501	size_t word_len);
duke@435	502	};
duke@435	503
duke@435	504	#define SCAN_AND_FORWARD(cp,scan_limit,block_is_obj,block_size) { \
duke@435	505	/* Compute the new addresses for the live objects and store it in the mark \
duke@435	506	* Used by universe::mark_sweep_phase2() \
duke@435	507	*/ \
duke@435	508	HeapWord* compact_top; /* This is where we are currently compacting to. */ \
duke@435	509	\
duke@435	510	/* We're sure to be here before any objects are compacted into this \
duke@435	511	* space, so this is a good time to initialize this: \
duke@435	512	*/ \
duke@435	513	set_compaction_top(bottom()); \
duke@435	514	\
duke@435	515	if (cp->space == NULL) { \
duke@435	516	assert(cp->gen != NULL, "need a generation"); \
duke@435	517	assert(cp->threshold == NULL, "just checking"); \
duke@435	518	assert(cp->gen->first_compaction_space() == this, "just checking"); \
duke@435	519	cp->space = cp->gen->first_compaction_space(); \
duke@435	520	compact_top = cp->space->bottom(); \
duke@435	521	cp->space->set_compaction_top(compact_top); \
duke@435	522	cp->threshold = cp->space->initialize_threshold(); \
duke@435	523	} else { \
duke@435	524	compact_top = cp->space->compaction_top(); \
duke@435	525	} \
duke@435	526	\
duke@435	527	/* We allow some amount of garbage towards the bottom of the space, so \
duke@435	528	* we don't start compacting before there is a significant gain to be made.\
duke@435	529	* Occasionally, we want to ensure a full compaction, which is determined \
duke@435	530	* by the MarkSweepAlwaysCompactCount parameter. \
duke@435	531	*/ \
duke@435	532	int invocations = SharedHeap::heap()->perm_gen()->stat_record()->invocations;\
duke@435	533	bool skip_dead = ((invocations % MarkSweepAlwaysCompactCount) != 0); \
duke@435	534	\
duke@435	535	size_t allowed_deadspace = 0; \
duke@435	536	if (skip_dead) { \
jcoomes@873	537	const size_t ratio = allowed_dead_ratio(); \
duke@435	538	allowed_deadspace = (capacity() * ratio / 100) / HeapWordSize; \
duke@435	539	} \
duke@435	540	\
duke@435	541	HeapWord* q = bottom(); \
duke@435	542	HeapWord* t = scan_limit(); \
duke@435	543	\
duke@435	544	HeapWord* end_of_live= q; /* One byte beyond the last byte of the last \
duke@435	545	live object. */ \
duke@435	546	HeapWord* first_dead = end();/* The first dead object. */ \
duke@435	547	LiveRange* liveRange = NULL; /* The current live range, recorded in the \
duke@435	548	first header of preceding free area. */ \
duke@435	549	_first_dead = first_dead; \
duke@435	550	\
duke@435	551	const intx interval = PrefetchScanIntervalInBytes; \
duke@435	552	\
duke@435	553	while (q < t) { \
duke@435	554	assert(!block_is_obj(q) || \
duke@435	555	oop(q)->mark()->is_marked() || oop(q)->mark()->is_unlocked() || \
duke@435	556	oop(q)->mark()->has_bias_pattern(), \
duke@435	557	"these are the only valid states during a mark sweep"); \
duke@435	558	if (block_is_obj(q) && oop(q)->is_gc_marked()) { \
duke@435	559	/* prefetch beyond q */ \
duke@435	560	Prefetch::write(q, interval); \
duke@435	561	/* size_t size = oop(q)->size(); changing this for cms for perm gen */\
ysr@777	562	size_t size = block_size(q); \
duke@435	563	compact_top = cp->space->forward(oop(q), size, cp, compact_top); \
duke@435	564	q += size; \
duke@435	565	end_of_live = q; \
duke@435	566	} else { \
duke@435	567	/* run over all the contiguous dead objects */ \
duke@435	568	HeapWord* end = q; \
duke@435	569	do { \
duke@435	570	/* prefetch beyond end */ \
duke@435	571	Prefetch::write(end, interval); \
duke@435	572	end += block_size(end); \
duke@435	573	} while (end < t && (!block_is_obj(end) || !oop(end)->is_gc_marked()));\
duke@435	574	\
duke@435	575	/* see if we might want to pretend this object is alive so that \
duke@435	576	* we don't have to compact quite as often. \
duke@435	577	*/ \
duke@435	578	if (allowed_deadspace > 0 && q == compact_top) { \
duke@435	579	size_t sz = pointer_delta(end, q); \
duke@435	580	if (insert_deadspace(allowed_deadspace, q, sz)) { \
duke@435	581	compact_top = cp->space->forward(oop(q), sz, cp, compact_top); \
duke@435	582	q = end; \
duke@435	583	end_of_live = end; \
duke@435	584	continue; \
duke@435	585	} \
duke@435	586	} \
duke@435	587	\
duke@435	588	/* otherwise, it really is a free region. */ \
duke@435	589	\
duke@435	590	/* for the previous LiveRange, record the end of the live objects. */ \
duke@435	591	if (liveRange) { \
duke@435	592	liveRange->set_end(q); \
duke@435	593	} \
duke@435	594	\
duke@435	595	/* record the current LiveRange object. \
duke@435	596	* liveRange->start() is overlaid on the mark word. \
duke@435	597	*/ \
duke@435	598	liveRange = (LiveRange*)q; \
duke@435	599	liveRange->set_start(end); \
duke@435	600	liveRange->set_end(end); \
duke@435	601	\
duke@435	602	/* see if this is the first dead region. */ \
duke@435	603	if (q < first_dead) { \
duke@435	604	first_dead = q; \
duke@435	605	} \
duke@435	606	\
duke@435	607	/* move on to the next object */ \
duke@435	608	q = end; \
duke@435	609	} \
duke@435	610	} \
duke@435	611	\
duke@435	612	assert(q == t, "just checking"); \
duke@435	613	if (liveRange != NULL) { \
duke@435	614	liveRange->set_end(q); \
duke@435	615	} \
duke@435	616	_end_of_live = end_of_live; \
duke@435	617	if (end_of_live < first_dead) { \
duke@435	618	first_dead = end_of_live; \
duke@435	619	} \
duke@435	620	_first_dead = first_dead; \
duke@435	621	\
duke@435	622	/* save the compaction_top of the compaction space. */ \
duke@435	623	cp->space->set_compaction_top(compact_top); \
duke@435	624	}
duke@435	625
ysr@777	626	#define SCAN_AND_ADJUST_POINTERS(adjust_obj_size) { \
ysr@777	627	/* adjust all the interior pointers to point at the new locations of objects \
ysr@777	628	* Used by MarkSweep::mark_sweep_phase3() */ \
duke@435	629	\
ysr@777	630	HeapWord* q = bottom(); \
ysr@777	631	HeapWord* t = _end_of_live; /* Established by "prepare_for_compaction". */ \
duke@435	632	\
ysr@777	633	assert(_first_dead <= _end_of_live, "Stands to reason, no?"); \
duke@435	634	\
ysr@777	635	if (q < t && _first_dead > q && \
duke@435	636	!oop(q)->is_gc_marked()) { \
duke@435	637	/* we have a chunk of the space which hasn't moved and we've \
duke@435	638	* reinitialized the mark word during the previous pass, so we can't \
ysr@777	639	* use is_gc_marked for the traversal. */ \
duke@435	640	HeapWord* end = _first_dead; \
duke@435	641	\
ysr@777	642	while (q < end) { \
ysr@777	643	/* I originally tried to conjoin "block_start(q) == q" to the \
ysr@777	644	* assertion below, but that doesn't work, because you can't \
ysr@777	645	* accurately traverse previous objects to get to the current one \
ysr@777	646	* after their pointers (including pointers into permGen) have been \
ysr@777	647	* updated, until the actual compaction is done. dld, 4/00 */ \
ysr@777	648	assert(block_is_obj(q), \
ysr@777	649	"should be at block boundaries, and should be looking at objs"); \
duke@435	650	\
coleenp@548	651	VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \
duke@435	652	\
ysr@777	653	/* point all the oops to the new location */ \
ysr@777	654	size_t size = oop(q)->adjust_pointers(); \
ysr@777	655	size = adjust_obj_size(size); \
duke@435	656	\
coleenp@548	657	VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \
ysr@777	658	\
coleenp@548	659	VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \
ysr@777	660	\
coleenp@548	661	q += size; \
ysr@777	662	} \
duke@435	663	\
ysr@777	664	if (_first_dead == t) { \
ysr@777	665	q = t; \
ysr@777	666	} else { \
ysr@777	667	/* $$$ This is funky. Using this to read the previously written \
ysr@777	668	* LiveRange. See also use below. */ \
duke@435	669	q = (HeapWord*)oop(_first_dead)->mark()->decode_pointer(); \
ysr@777	670	} \
ysr@777	671	} \
duke@435	672	\
duke@435	673	const intx interval = PrefetchScanIntervalInBytes; \
duke@435	674	\
ysr@777	675	debug_only(HeapWord* prev_q = NULL); \
ysr@777	676	while (q < t) { \
ysr@777	677	/* prefetch beyond q */ \
duke@435	678	Prefetch::write(q, interval); \
ysr@777	679	if (oop(q)->is_gc_marked()) { \
ysr@777	680	/* q is alive */ \
coleenp@548	681	VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \
ysr@777	682	/* point all the oops to the new location */ \
ysr@777	683	size_t size = oop(q)->adjust_pointers(); \
ysr@777	684	size = adjust_obj_size(size); \
ysr@777	685	VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \
coleenp@548	686	VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \
ysr@777	687	debug_only(prev_q = q); \
duke@435	688	q += size; \
tonyp@791	689	} else { \
tonyp@791	690	/* q is not a live object, so its mark should point at the next \
tonyp@791	691	* live object */ \
tonyp@791	692	debug_only(prev_q = q); \
tonyp@791	693	q = (HeapWord*) oop(q)->mark()->decode_pointer(); \
tonyp@791	694	assert(q > prev_q, "we should be moving forward through memory"); \
tonyp@791	695	} \
tonyp@791	696	} \
duke@435	697	\
tonyp@791	698	assert(q == t, "just checking"); \
duke@435	699	}
duke@435	700
tonyp@791	701	#define SCAN_AND_COMPACT(obj_size) { \
duke@435	702	/* Copy all live objects to their new location \
tonyp@791	703	* Used by MarkSweep::mark_sweep_phase4() */ \
duke@435	704	\
tonyp@791	705	HeapWord* q = bottom(); \
tonyp@791	706	HeapWord* const t = _end_of_live; \
tonyp@791	707	debug_only(HeapWord* prev_q = NULL); \
duke@435	708	\
tonyp@791	709	if (q < t && _first_dead > q && \
duke@435	710	!oop(q)->is_gc_marked()) { \
tonyp@791	711	debug_only( \
coleenp@548	712	/* we have a chunk of the space which hasn't moved and we've reinitialized \
coleenp@548	713	* the mark word during the previous pass, so we can't use is_gc_marked for \
coleenp@548	714	* the traversal. */ \
tonyp@791	715	HeapWord* const end = _first_dead; \
tonyp@791	716	\
tonyp@791	717	while (q < end) { \
coleenp@548	718	size_t size = obj_size(q); \
coleenp@548	719	assert(!oop(q)->is_gc_marked(), \
coleenp@548	720	"should be unmarked (special dense prefix handling)"); \
tonyp@791	721	VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, q)); \
tonyp@791	722	debug_only(prev_q = q); \
coleenp@548	723	q += size; \
tonyp@791	724	} \
tonyp@791	725	) /* debug_only */ \
duke@435	726	\
tonyp@791	727	if (_first_dead == t) { \
tonyp@791	728	q = t; \
tonyp@791	729	} else { \
tonyp@791	730	/* $$$ Funky */ \
tonyp@791	731	q = (HeapWord*) oop(_first_dead)->mark()->decode_pointer(); \
tonyp@791	732	} \
tonyp@791	733	} \
tonyp@791	734	\
tonyp@791	735	const intx scan_interval = PrefetchScanIntervalInBytes; \
tonyp@791	736	const intx copy_interval = PrefetchCopyIntervalInBytes; \
tonyp@791	737	while (q < t) { \
tonyp@791	738	if (!oop(q)->is_gc_marked()) { \
tonyp@791	739	/* mark is pointer to next marked oop */ \
tonyp@791	740	debug_only(prev_q = q); \
tonyp@791	741	q = (HeapWord*) oop(q)->mark()->decode_pointer(); \
tonyp@791	742	assert(q > prev_q, "we should be moving forward through memory"); \
tonyp@791	743	} else { \
tonyp@791	744	/* prefetch beyond q */ \
duke@435	745	Prefetch::read(q, scan_interval); \
duke@435	746	\
duke@435	747	/* size and destination */ \
duke@435	748	size_t size = obj_size(q); \
duke@435	749	HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee(); \
duke@435	750	\
tonyp@791	751	/* prefetch beyond compaction_top */ \
duke@435	752	Prefetch::write(compaction_top, copy_interval); \
duke@435	753	\
tonyp@791	754	/* copy object and reinit its mark */ \
coleenp@548	755	VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, \
coleenp@548	756	compaction_top)); \
tonyp@791	757	assert(q != compaction_top, "everything in this pass should be moving"); \
tonyp@791	758	Copy::aligned_conjoint_words(q, compaction_top, size); \
tonyp@791	759	oop(compaction_top)->init_mark(); \
tonyp@791	760	assert(oop(compaction_top)->klass() != NULL, "should have a class"); \
duke@435	761	\
tonyp@791	762	debug_only(prev_q = q); \
duke@435	763	q += size; \
tonyp@791	764	} \
tonyp@791	765	} \
duke@435	766	\
ysr@777	767	/* Let's remember if we were empty before we did the compaction. */ \
ysr@777	768	bool was_empty = used_region().is_empty(); \
duke@435	769	/* Reset space after compaction is complete */ \
tonyp@791	770	reset_after_compaction(); \
duke@435	771	/* We do this clear, below, since it has overloaded meanings for some */ \
duke@435	772	/* space subtypes. For example, OffsetTableContigSpace's that were */ \
duke@435	773	/* compacted into will have had their offset table thresholds updated */ \
duke@435	774	/* continuously, but those that weren't need to have their thresholds */ \
duke@435	775	/* re-initialized. Also mangles unused area for debugging. */ \
ysr@777	776	if (used_region().is_empty()) { \
tonyp@791	777	if (!was_empty) clear(SpaceDecorator::Mangle); \
duke@435	778	} else { \
duke@435	779	if (ZapUnusedHeapArea) mangle_unused_area(); \
duke@435	780	} \
duke@435	781	}
duke@435	782
jmasa@698	783	class GenSpaceMangler;
jmasa@698	784
duke@435	785	// A space in which the free area is contiguous. It therefore supports
duke@435	786	// faster allocation, and compaction.
duke@435	787	class ContiguousSpace: public CompactibleSpace {
duke@435	788	friend class OneContigSpaceCardGeneration;
duke@435	789	friend class VMStructs;
duke@435	790	protected:
duke@435	791	HeapWord* _top;
duke@435	792	HeapWord* _concurrent_iteration_safe_limit;
jmasa@698	793	// A helper for mangling the unused area of the space in debug builds.
jmasa@698	794	GenSpaceMangler* _mangler;
jmasa@698	795
jmasa@698	796	GenSpaceMangler* mangler() { return _mangler; }
duke@435	797
duke@435	798	// Allocation helpers (return NULL if full).
duke@435	799	inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value);
duke@435	800	inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value);
duke@435	801
duke@435	802	public:
jmasa@698	803	ContiguousSpace();
jmasa@698	804	~ContiguousSpace();
jmasa@698	805
jmasa@698	806	virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
tonyp@791	807	virtual void clear(bool mangle_space);
duke@435	808
duke@435	809	// Accessors
duke@435	810	HeapWord* top() const { return _top; }
duke@435	811	void set_top(HeapWord* value) { _top = value; }
duke@435	812
ysr@777	813	virtual void set_saved_mark() { _saved_mark_word = top(); }
ysr@777	814	void reset_saved_mark() { _saved_mark_word = bottom(); }
duke@435	815
duke@435	816	WaterMark bottom_mark() { return WaterMark(this, bottom()); }
duke@435	817	WaterMark top_mark() { return WaterMark(this, top()); }
duke@435	818	WaterMark saved_mark() { return WaterMark(this, saved_mark_word()); }
duke@435	819	bool saved_mark_at_top() const { return saved_mark_word() == top(); }
duke@435	820
jmasa@698	821	// In debug mode mangle (write it with a particular bit
jmasa@698	822	// pattern) the unused part of a space.
jmasa@698	823
jmasa@698	824	// Used to save the an address in a space for later use during mangling.
jmasa@698	825	void set_top_for_allocations(HeapWord* v) PRODUCT_RETURN;
jmasa@698	826	// Used to save the space's current top for later use during mangling.
jmasa@698	827	void set_top_for_allocations() PRODUCT_RETURN;
jmasa@698	828
jmasa@698	829	// Mangle regions in the space from the current top up to the
jmasa@698	830	// previously mangled part of the space.
jmasa@698	831	void mangle_unused_area() PRODUCT_RETURN;
jmasa@698	832	// Mangle [top, end)
jmasa@698	833	void mangle_unused_area_complete() PRODUCT_RETURN;
jmasa@698	834	// Mangle the given MemRegion.
jmasa@698	835	void mangle_region(MemRegion mr) PRODUCT_RETURN;
jmasa@698	836
jmasa@698	837	// Do some sparse checking on the area that should have been mangled.
jmasa@698	838	void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN;
jmasa@698	839	// Check the complete area that should have been mangled.
jmasa@698	840	// This code may be NULL depending on the macro DEBUG_MANGLING.
jmasa@698	841	void check_mangled_unused_area_complete() PRODUCT_RETURN;
duke@435	842
duke@435	843	// Size computations: sizes in bytes.
duke@435	844	size_t capacity() const { return byte_size(bottom(), end()); }
duke@435	845	size_t used() const { return byte_size(bottom(), top()); }
duke@435	846	size_t free() const { return byte_size(top(), end()); }
duke@435	847
duke@435	848	// Override from space.
duke@435	849	bool is_in(const void* p) const;
duke@435	850
duke@435	851	virtual bool is_free_block(const HeapWord* p) const;
duke@435	852
duke@435	853	// In a contiguous space we have a more obvious bound on what parts
duke@435	854	// contain objects.
duke@435	855	MemRegion used_region() const { return MemRegion(bottom(), top()); }
duke@435	856
duke@435	857	MemRegion used_region_at_save_marks() const {
duke@435	858	return MemRegion(bottom(), saved_mark_word());
duke@435	859	}
duke@435	860
duke@435	861	// Allocation (return NULL if full)
duke@435	862	virtual HeapWord* allocate(size_t word_size);
duke@435	863	virtual HeapWord* par_allocate(size_t word_size);
duke@435	864
duke@435	865	virtual bool obj_allocated_since_save_marks(const oop obj) const {
duke@435	866	return (HeapWord*)obj >= saved_mark_word();
duke@435	867	}
duke@435	868
duke@435	869	// Iteration
duke@435	870	void oop_iterate(OopClosure* cl);
duke@435	871	void oop_iterate(MemRegion mr, OopClosure* cl);
duke@435	872	void object_iterate(ObjectClosure* blk);
jmasa@952	873	// For contiguous spaces this method will iterate safely over objects
jmasa@952	874	// in the space (i.e., between bottom and top) when at a safepoint.
jmasa@952	875	void safe_object_iterate(ObjectClosure* blk);
duke@435	876	void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl);
duke@435	877	// iterates on objects up to the safe limit
duke@435	878	HeapWord* object_iterate_careful(ObjectClosureCareful* cl);
duke@435	879	inline HeapWord* concurrent_iteration_safe_limit();
duke@435	880	// changes the safe limit, all objects from bottom() to the new
duke@435	881	// limit should be properly initialized
duke@435	882	inline void set_concurrent_iteration_safe_limit(HeapWord* new_limit);
duke@435	883
duke@435	884	#ifndef SERIALGC
duke@435	885	// In support of parallel oop_iterate.
duke@435	886	#define ContigSpace_PAR_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
duke@435	887	void par_oop_iterate(MemRegion mr, OopClosureType* blk);
duke@435	888
duke@435	889	ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DECL)
duke@435	890	#undef ContigSpace_PAR_OOP_ITERATE_DECL
duke@435	891	#endif // SERIALGC
duke@435	892
duke@435	893	// Compaction support
duke@435	894	virtual void reset_after_compaction() {
duke@435	895	assert(compaction_top() >= bottom() && compaction_top() <= end(), "should point inside space");
duke@435	896	set_top(compaction_top());
duke@435	897	// set new iteration safe limit
duke@435	898	set_concurrent_iteration_safe_limit(compaction_top());
duke@435	899	}
duke@435	900	virtual size_t minimum_free_block_size() const { return 0; }
duke@435	901
duke@435	902	// Override.
duke@435	903	DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl,
duke@435	904	CardTableModRefBS::PrecisionStyle precision,
duke@435	905	HeapWord* boundary = NULL);
duke@435	906
duke@435	907	// Apply "blk->do_oop" to the addresses of all reference fields in objects
duke@435	908	// starting with the _saved_mark_word, which was noted during a generation's
duke@435	909	// save_marks and is required to denote the head of an object.
duke@435	910	// Fields in objects allocated by applications of the closure
duke@435	911	// *are* included in the iteration.
duke@435	912	// Updates _saved_mark_word to point to just after the last object
duke@435	913	// iterated over.
duke@435	914	#define ContigSpace_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
duke@435	915	void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk);
duke@435	916
duke@435	917	ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DECL)
duke@435	918	#undef ContigSpace_OOP_SINCE_SAVE_MARKS_DECL
duke@435	919
duke@435	920	// Same as object_iterate, but starting from "mark", which is required
duke@435	921	// to denote the start of an object. Objects allocated by
duke@435	922	// applications of the closure *are* included in the iteration.
duke@435	923	virtual void object_iterate_from(WaterMark mark, ObjectClosure* blk);
duke@435	924
duke@435	925	// Very inefficient implementation.
ysr@777	926	virtual HeapWord* block_start_const(const void* p) const;
duke@435	927	size_t block_size(const HeapWord* p) const;
duke@435	928	// If a block is in the allocated area, it is an object.
duke@435	929	bool block_is_obj(const HeapWord* p) const { return p < top(); }
duke@435	930
duke@435	931	// Addresses for inlined allocation
duke@435	932	HeapWord** top_addr() { return &_top; }
duke@435	933	HeapWord** end_addr() { return &_end; }
duke@435	934
duke@435	935	// Overrides for more efficient compaction support.
duke@435	936	void prepare_for_compaction(CompactPoint* cp);
duke@435	937
duke@435	938	// PrintHeapAtGC support.
duke@435	939	virtual void print_on(outputStream* st) const;
duke@435	940
duke@435	941	// Checked dynamic downcasts.
duke@435	942	virtual ContiguousSpace* toContiguousSpace() {
duke@435	943	return this;
duke@435	944	}
duke@435	945
duke@435	946	// Debugging
duke@435	947	virtual void verify(bool allow_dirty) const;
duke@435	948
duke@435	949	// Used to increase collection frequency. "factor" of 0 means entire
duke@435	950	// space.
duke@435	951	void allocate_temporary_filler(int factor);
duke@435	952
duke@435	953	};
duke@435	954
duke@435	955
duke@435	956	// A dirty card to oop closure that does filtering.
duke@435	957	// It knows how to filter out objects that are outside of the _boundary.
duke@435	958	class Filtering_DCTOC : public DirtyCardToOopClosure {
duke@435	959	protected:
duke@435	960	// Override.
duke@435	961	void walk_mem_region(MemRegion mr,
duke@435	962	HeapWord* bottom, HeapWord* top);
duke@435	963
duke@435	964	// Walk the given memory region, from bottom to top, applying
duke@435	965	// the given oop closure to (possibly) all objects found. The
duke@435	966	// given oop closure may or may not be the same as the oop
duke@435	967	// closure with which this closure was created, as it may
duke@435	968	// be a filtering closure which makes use of the _boundary.
duke@435	969	// We offer two signatures, so the FilteringClosure static type is
duke@435	970	// apparent.
duke@435	971	virtual void walk_mem_region_with_cl(MemRegion mr,
duke@435	972	HeapWord* bottom, HeapWord* top,
duke@435	973	OopClosure* cl) = 0;
duke@435	974	virtual void walk_mem_region_with_cl(MemRegion mr,
duke@435	975	HeapWord* bottom, HeapWord* top,
duke@435	976	FilteringClosure* cl) = 0;
duke@435	977
duke@435	978	public:
duke@435	979	Filtering_DCTOC(Space* sp, OopClosure* cl,
duke@435	980	CardTableModRefBS::PrecisionStyle precision,
duke@435	981	HeapWord* boundary) :
duke@435	982	DirtyCardToOopClosure(sp, cl, precision, boundary) {}
duke@435	983	};
duke@435	984
duke@435	985	// A dirty card to oop closure for contiguous spaces
duke@435	986	// (ContiguousSpace and sub-classes).
duke@435	987	// It is a FilteringClosure, as defined above, and it knows:
duke@435	988	//
duke@435	989	// 1. That the actual top of any area in a memory region
duke@435	990	// contained by the space is bounded by the end of the contiguous
duke@435	991	// region of the space.
duke@435	992	// 2. That the space is really made up of objects and not just
duke@435	993	// blocks.
duke@435	994
duke@435	995	class ContiguousSpaceDCTOC : public Filtering_DCTOC {
duke@435	996	protected:
duke@435	997	// Overrides.
duke@435	998	HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj);
duke@435	999
duke@435	1000	virtual void walk_mem_region_with_cl(MemRegion mr,
duke@435	1001	HeapWord* bottom, HeapWord* top,
duke@435	1002	OopClosure* cl);
duke@435	1003	virtual void walk_mem_region_with_cl(MemRegion mr,
duke@435	1004	HeapWord* bottom, HeapWord* top,
duke@435	1005	FilteringClosure* cl);
duke@435	1006
duke@435	1007	public:
duke@435	1008	ContiguousSpaceDCTOC(ContiguousSpace* sp, OopClosure* cl,
duke@435	1009	CardTableModRefBS::PrecisionStyle precision,
duke@435	1010	HeapWord* boundary) :
duke@435	1011	Filtering_DCTOC(sp, cl, precision, boundary)
duke@435	1012	{}
duke@435	1013	};
duke@435	1014
duke@435	1015
duke@435	1016	// Class EdenSpace describes eden-space in new generation.
duke@435	1017
duke@435	1018	class DefNewGeneration;
duke@435	1019
duke@435	1020	class EdenSpace : public ContiguousSpace {
duke@435	1021	friend class VMStructs;
duke@435	1022	private:
duke@435	1023	DefNewGeneration* _gen;
duke@435	1024
duke@435	1025	// _soft_end is used as a soft limit on allocation. As soft limits are
duke@435	1026	// reached, the slow-path allocation code can invoke other actions and then
duke@435	1027	// adjust _soft_end up to a new soft limit or to end().
duke@435	1028	HeapWord* _soft_end;
duke@435	1029
duke@435	1030	public:
ysr@782	1031	EdenSpace(DefNewGeneration* gen) :
ysr@782	1032	_gen(gen), _soft_end(NULL) {}
duke@435	1033
duke@435	1034	// Get/set just the 'soft' limit.
duke@435	1035	HeapWord* soft_end() { return _soft_end; }
duke@435	1036	HeapWord** soft_end_addr() { return &_soft_end; }
duke@435	1037	void set_soft_end(HeapWord* value) { _soft_end = value; }
duke@435	1038
duke@435	1039	// Override.
jmasa@698	1040	void clear(bool mangle_space);
duke@435	1041
duke@435	1042	// Set both the 'hard' and 'soft' limits (_end and _soft_end).
duke@435	1043	void set_end(HeapWord* value) {
duke@435	1044	set_soft_end(value);
duke@435	1045	ContiguousSpace::set_end(value);
duke@435	1046	}
duke@435	1047
duke@435	1048	// Allocation (return NULL if full)
duke@435	1049	HeapWord* allocate(size_t word_size);
duke@435	1050	HeapWord* par_allocate(size_t word_size);
duke@435	1051	};
duke@435	1052
duke@435	1053	// Class ConcEdenSpace extends EdenSpace for the sake of safe
duke@435	1054	// allocation while soft-end is being modified concurrently
duke@435	1055
duke@435	1056	class ConcEdenSpace : public EdenSpace {
duke@435	1057	public:
duke@435	1058	ConcEdenSpace(DefNewGeneration* gen) : EdenSpace(gen) { }
duke@435	1059
duke@435	1060	// Allocation (return NULL if full)
duke@435	1061	HeapWord* par_allocate(size_t word_size);
duke@435	1062	};
duke@435	1063
duke@435	1064
duke@435	1065	// A ContigSpace that Supports an efficient "block_start" operation via
duke@435	1066	// a BlockOffsetArray (whose BlockOffsetSharedArray may be shared with
duke@435	1067	// other spaces.) This is the abstract base class for old generation
duke@435	1068	// (tenured, perm) spaces.
duke@435	1069
duke@435	1070	class OffsetTableContigSpace: public ContiguousSpace {
duke@435	1071	friend class VMStructs;
duke@435	1072	protected:
duke@435	1073	BlockOffsetArrayContigSpace _offsets;
duke@435	1074	Mutex _par_alloc_lock;
duke@435	1075
duke@435	1076	public:
duke@435	1077	// Constructor
duke@435	1078	OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray,
duke@435	1079	MemRegion mr);
duke@435	1080
duke@435	1081	void set_bottom(HeapWord* value);
duke@435	1082	void set_end(HeapWord* value);
duke@435	1083
jmasa@698	1084	void clear(bool mangle_space);
duke@435	1085
ysr@777	1086	inline HeapWord* block_start_const(const void* p) const;
duke@435	1087
duke@435	1088	// Add offset table update.
duke@435	1089	virtual inline HeapWord* allocate(size_t word_size);
duke@435	1090	inline HeapWord* par_allocate(size_t word_size);
duke@435	1091
duke@435	1092	// MarkSweep support phase3
duke@435	1093	virtual HeapWord* initialize_threshold();
duke@435	1094	virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
duke@435	1095
duke@435	1096	virtual void print_on(outputStream* st) const;
duke@435	1097
duke@435	1098	// Debugging
duke@435	1099	void verify(bool allow_dirty) const;
duke@435	1100
duke@435	1101	// Shared space support
duke@435	1102	void serialize_block_offset_array_offsets(SerializeOopClosure* soc);
duke@435	1103	};
duke@435	1104
duke@435	1105
duke@435	1106	// Class TenuredSpace is used by TenuredGeneration
duke@435	1107
duke@435	1108	class TenuredSpace: public OffsetTableContigSpace {
duke@435	1109	friend class VMStructs;
duke@435	1110	protected:
duke@435	1111	// Mark sweep support
jcoomes@873	1112	size_t allowed_dead_ratio() const;
duke@435	1113	public:
duke@435	1114	// Constructor
duke@435	1115	TenuredSpace(BlockOffsetSharedArray* sharedOffsetArray,
duke@435	1116	MemRegion mr) :
duke@435	1117	OffsetTableContigSpace(sharedOffsetArray, mr) {}
duke@435	1118	};
duke@435	1119
duke@435	1120
duke@435	1121	// Class ContigPermSpace is used by CompactingPermGen
duke@435	1122
duke@435	1123	class ContigPermSpace: public OffsetTableContigSpace {
duke@435	1124	friend class VMStructs;
duke@435	1125	protected:
duke@435	1126	// Mark sweep support
jcoomes@873	1127	size_t allowed_dead_ratio() const;
duke@435	1128	public:
duke@435	1129	// Constructor
duke@435	1130	ContigPermSpace(BlockOffsetSharedArray* sharedOffsetArray, MemRegion mr) :
duke@435	1131	OffsetTableContigSpace(sharedOffsetArray, mr) {}
duke@435	1132	};
stefank@2314	1133
stefank@2314	1134	#endif // SHARE_VM_MEMORY_SPACE_HPP