1 #ifdef USE_PRAGMA_IDENT_HDR
2 #pragma ident "@(#)psYoungGen.hpp 1.48 07/05/05 17:05:31 JVM"
3 #endif
4 /*
5 * Copyright 2001-2008 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 class PSMarkSweepDecorator;
29
30 class PSYoungGen : public CHeapObj {
31 friend class VMStructs;
32 friend class ParallelScavengeHeap;
33 friend class AdjoiningGenerations;
34
35 protected:
36 MemRegion _reserved;
37 PSVirtualSpace* _virtual_space;
38
39 // Spaces
40 MutableSpace* _eden_space;
41 MutableSpace* _from_space;
42 MutableSpace* _to_space;
43
44
45 // MarkSweep Decorators
46 PSMarkSweepDecorator* _eden_mark_sweep;
47 PSMarkSweepDecorator* _from_mark_sweep;
48 PSMarkSweepDecorator* _to_mark_sweep;
49
50 // Sizing information, in bytes, set in constructor
51 const size_t _init_gen_size;
52 const size_t _min_gen_size;
53 const size_t _max_gen_size;
54
55 // Performance counters
56 PSGenerationCounters* _gen_counters;
57 SpaceCounters* _eden_counters;
58 SpaceCounters* _from_counters;
59 SpaceCounters* _to_counters;
60
61 // Initialize the space boundaries
62 void compute_initial_space_boundaries();
63
64 // Space boundary helper
65 void set_space_boundaries(size_t eden_size, size_t survivor_size);
66
67 virtual bool resize_generation(size_t eden_size, size_t survivor_size);
68 virtual void resize_spaces(size_t eden_size, size_t survivor_size);
69
70 // Adjust the spaces to be consistent with the virtual space.
71 void post_resize();
72
73 // Return number of bytes that the generation can change.
74 // These should not be used by PSYoungGen
75 virtual size_t available_for_expansion();
76 virtual size_t available_for_contraction();
77
78 // Given a desired shrinkage in the size of the young generation,
79 // return the actual size available for shrinkage.
80 virtual size_t limit_gen_shrink(size_t desired_change);
81 // returns the number of bytes available from the current size
82 // down to the minimum generation size.
83 size_t available_to_min_gen();
84 // Return the number of bytes available for shrinkage considering
85 // the location the live data in the generation.
86 virtual size_t available_to_live();
87
88 public:
89 // Initialize the generation.
90 PSYoungGen(size_t initial_byte_size,
91 size_t minimum_byte_size,
92 size_t maximum_byte_size);
93 void initialize_work();
94 virtual void initialize(ReservedSpace rs, size_t alignment);
95 virtual void initialize_virtual_space(ReservedSpace rs, size_t alignment);
96
97 MemRegion reserved() const { return _reserved; }
98
99 bool is_in(const void* p) const {
100 return _virtual_space->contains((void *)p);
101 }
102
103 bool is_in_reserved(const void* p) const {
104 return reserved().contains((void *)p);
105 }
106
107 MutableSpace* eden_space() const { return _eden_space; }
108 MutableSpace* from_space() const { return _from_space; }
109 MutableSpace* to_space() const { return _to_space; }
110 PSVirtualSpace* virtual_space() const { return _virtual_space; }
111
112 // For Adaptive size policy
113 size_t min_gen_size() { return _min_gen_size; }
114
115 // MarkSweep support
116 PSMarkSweepDecorator* eden_mark_sweep() const { return _eden_mark_sweep; }
117 PSMarkSweepDecorator* from_mark_sweep() const { return _from_mark_sweep; }
118 PSMarkSweepDecorator* to_mark_sweep() const { return _to_mark_sweep; }
119
120 void precompact();
121 void adjust_pointers();
122 void compact();
123
124 // Parallel Old
125 void move_and_update(ParCompactionManager* cm);
126
127 // Called during/after gc
128 void swap_spaces();
129
130 // Resize generation using suggested free space size and survivor size
131 // NOTE: "eden_size" and "survivor_size" are suggestions only. Current
132 // heap layout (particularly, live objects in from space) might
133 // not allow us to use these values.
134 void resize(size_t eden_size, size_t survivor_size);
135
136 // Size info
137 size_t capacity_in_bytes() const;
138 size_t used_in_bytes() const;
139 size_t free_in_bytes() const;
140
141 size_t capacity_in_words() const;
142 size_t used_in_words() const;
143 size_t free_in_words() const;
144
145 // The max this generation can grow to
146 size_t max_size() const { return _reserved.byte_size(); }
147
148 // The max this generation can grow to if the boundary between
149 // the generations are allowed to move.
150 size_t gen_size_limit() const { return _max_gen_size; }
151
152 bool is_maximal_no_gc() const {
153 return true; // never expands except at a GC
154 }
155
156 // Allocation
157 HeapWord* allocate(size_t word_size, bool is_tlab) {
158 HeapWord* result = eden_space()->cas_allocate(word_size);
159 return result;
160 }
161
162 HeapWord** top_addr() const { return eden_space()->top_addr(); }
163 HeapWord** end_addr() const { return eden_space()->end_addr(); }
164
165 // Iteration.
166 void oop_iterate(OopClosure* cl);
167 void object_iterate(ObjectClosure* cl);
168
169 virtual void reset_after_change();
170 virtual void reset_survivors_after_shrink();
171
172 // Performance Counter support
173 void update_counters();
174
175 // Debugging - do not use for time critical operations
176 void print() const;
177 void print_on(outputStream* st) const;
178 void print_used_change(size_t prev_used) const;
179 virtual const char* name() const { return "PSYoungGen"; }
180
181 void verify(bool allow_dirty);
182
183 // Space boundary invariant checker
184 void space_invariants() PRODUCT_RETURN;
185
186 // Helper for mangling survivor spaces.
187 void mangle_survivors(MutableSpace* s1,
188 MemRegion s1MR,
189 MutableSpace* s2,
190 MemRegion s2MR) PRODUCT_RETURN;
191
192 void record_spaces_top() PRODUCT_RETURN;
193 };