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src/share/vm/gc_implementation/parallelScavenge/psPromotionLAB.hpp@ba764ed4b6f2 (annotated)

src/share/vm/gc_implementation/parallelScavenge/psPromotionLAB.hpp

Sun, 13 Apr 2008 17:43:42 -0400

author

coleenp

date

Sun, 13 Apr 2008 17:43:42 -0400

changeset 548

ba764ed4b6f2

parent 435

a61af66fc99e

child 631

d1605aabd0a1

permissions

-rw-r--r--

6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
Summary: Compressed oops in instances, arrays, and headers. Code contributors are coleenp, phh, never, swamyv
Reviewed-by: jmasa, kamg, acorn, tbell, kvn, rasbold

duke@435	1	/*
duke@435	2	* Copyright 2002 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	//
duke@435	26	// PSPromotionLAB is a parallel scavenge promotion lab. This class acts very
duke@435	27	// much like a MutableSpace. We couldn't embed a MutableSpace, though, as
duke@435	28	// it has a considerable number of asserts and invariants that are violated.
duke@435	29	//
duke@435	30
duke@435	31	class ObjectStartArray;
duke@435	32
duke@435	33	class PSPromotionLAB : public CHeapObj {
duke@435	34	protected:
coleenp@548	35	static size_t filler_header_size;
duke@435	36
duke@435	37	enum LabState {
duke@435	38	needs_flush,
duke@435	39	flushed,
duke@435	40	zero_size
duke@435	41	};
duke@435	42
duke@435	43	HeapWord* _top;
duke@435	44	HeapWord* _bottom;
duke@435	45	HeapWord* _end;
duke@435	46	LabState _state;
duke@435	47
duke@435	48	void set_top(HeapWord* value) { _top = value; }
duke@435	49	void set_bottom(HeapWord* value) { _bottom = value; }
duke@435	50	void set_end(HeapWord* value) { _end = value; }
duke@435	51
duke@435	52	// The shared initialize code invokes this.
duke@435	53	debug_only(virtual bool lab_is_valid(MemRegion lab) { return false; });
duke@435	54
duke@435	55	PSPromotionLAB() : _top(NULL), _bottom(NULL), _end(NULL) { }
duke@435	56
duke@435	57	public:
duke@435	58	// Filling and flushing.
duke@435	59	void initialize(MemRegion lab);
duke@435	60
duke@435	61	virtual void flush();
duke@435	62
duke@435	63	// Accessors
duke@435	64	HeapWord* bottom() const { return _bottom; }
duke@435	65	HeapWord* end() const { return _end; }
duke@435	66	HeapWord* top() const { return _top; }
duke@435	67
duke@435	68	bool is_flushed() { return _state == flushed; }
duke@435	69
duke@435	70	bool unallocate_object(oop obj);
duke@435	71
duke@435	72	// Returns a subregion containing all objects in this space.
duke@435	73	MemRegion used_region() { return MemRegion(bottom(), top()); }
duke@435	74
duke@435	75	// Boolean querries.
duke@435	76	bool is_empty() const { return used() == 0; }
duke@435	77	bool not_empty() const { return used() > 0; }
duke@435	78	bool contains(const void* p) const { return _bottom <= p && p < _end; }
duke@435	79
duke@435	80	// Size computations. Sizes are in bytes.
duke@435	81	size_t capacity() const { return byte_size(bottom(), end()); }
duke@435	82	size_t used() const { return byte_size(bottom(), top()); }
duke@435	83	size_t free() const { return byte_size(top(), end()); }
duke@435	84	};
duke@435	85
duke@435	86	class PSYoungPromotionLAB : public PSPromotionLAB {
duke@435	87	public:
duke@435	88	PSYoungPromotionLAB() { }
duke@435	89
duke@435	90	// Not MT safe
duke@435	91	HeapWord* allocate(size_t size) {
duke@435	92	// Can't assert this, when young fills, we keep the LAB around, but flushed.
duke@435	93	// assert(_state != flushed, "Sanity");
duke@435	94	HeapWord* obj = top();
duke@435	95	HeapWord* new_top = obj + size;
duke@435	96	// The 'new_top>obj' check is needed to detect overflow of obj+size.
duke@435	97	if (new_top > obj && new_top <= end()) {
duke@435	98	set_top(new_top);
duke@435	99	assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
duke@435	100	"checking alignment");
duke@435	101	return obj;
duke@435	102	}
duke@435	103
duke@435	104	return NULL;
duke@435	105	}
duke@435	106
duke@435	107	debug_only(virtual bool lab_is_valid(MemRegion lab));
duke@435	108	};
duke@435	109
duke@435	110	class PSOldPromotionLAB : public PSPromotionLAB {
duke@435	111	private:
duke@435	112	ObjectStartArray* _start_array;
duke@435	113
duke@435	114	public:
duke@435	115	PSOldPromotionLAB() : _start_array(NULL) { }
duke@435	116	PSOldPromotionLAB(ObjectStartArray* start_array) : _start_array(start_array) { }
duke@435	117
duke@435	118	void set_start_array(ObjectStartArray* start_array) { _start_array = start_array; }
duke@435	119
duke@435	120	void flush();
duke@435	121
duke@435	122	// Not MT safe
duke@435	123	HeapWord* allocate(size_t size) {
duke@435	124	// Cannot test for this now that we're doing promotion failures
duke@435	125	// assert(_state != flushed, "Sanity");
duke@435	126	assert(_start_array != NULL, "Sanity");
duke@435	127	HeapWord* obj = top();
duke@435	128	HeapWord* new_top = obj + size;
duke@435	129	// The 'new_top>obj' check is needed to detect overflow of obj+size.
duke@435	130	if (new_top > obj && new_top <= end()) {
duke@435	131	set_top(new_top);
duke@435	132	assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
duke@435	133	"checking alignment");
duke@435	134	_start_array->allocate_block(obj);
duke@435	135	return obj;
duke@435	136	}
duke@435	137
duke@435	138	return NULL;
duke@435	139	}
duke@435	140
duke@435	141	debug_only(virtual bool lab_is_valid(MemRegion lab));
duke@435	142	};