1 /*
2 * Copyright 2001-2008 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 class PSMarkSweepDecorator;
26
27 class PSYoungGen : public CHeapObj {
28 friend class VMStructs;
29 friend class ParallelScavengeHeap;
30 friend class AdjoiningGenerations;
31
32 protected:
33 MemRegion _reserved;
34 PSVirtualSpace* _virtual_space;
35
36 // Spaces
37 MutableSpace* _eden_space;
38 MutableSpace* _from_space;
39 MutableSpace* _to_space;
40
41
42 // MarkSweep Decorators
43 PSMarkSweepDecorator* _eden_mark_sweep;
44 PSMarkSweepDecorator* _from_mark_sweep;
45 PSMarkSweepDecorator* _to_mark_sweep;
46
47 // Sizing information, in bytes, set in constructor
48 const size_t _init_gen_size;
49 const size_t _min_gen_size;
50 const size_t _max_gen_size;
51
52 size_t _init_survivor_size;
53 size_t _init_eden_size;
54 size_t _max_survivor_size;
55 size_t _max_eden_size;
56
57 // Performance counters
58 PSGenerationCounters* _gen_counters;
59 SpaceCounters* _eden_counters;
60 SpaceCounters* _from_counters;
61 SpaceCounters* _to_counters;
62
63 // Initialize the space boundaries
64 void compute_initial_space_boundaries();
65
66 // Space boundary helper
67 void set_space_boundaries(size_t eden_size, size_t survivor_size);
68
69 virtual bool resize_generation(size_t eden_size, size_t survivor_size);
70 virtual void resize_spaces(size_t eden_size, size_t survivor_size);
71
72 // Adjust the spaces to be consistent with the virtual space.
73 void post_resize();
74
75 // Return number of bytes that the generation can change.
76 // These should not be used by PSYoungGen
77 virtual size_t available_for_expansion();
78 virtual size_t available_for_contraction();
79
80 // Given a desired shrinkage in the size of the young generation,
81 // return the actual size available for shrinkage.
82 virtual size_t limit_gen_shrink(size_t desired_change);
83 // returns the number of bytes available from the current size
84 // down to the minimum generation size.
85 size_t available_to_min_gen();
86 // Return the number of bytes available for shrinkage considering
87 // the location the live data in the generation.
88 virtual size_t available_to_live();
89
90 public:
91 // Initialize the generation.
92 PSYoungGen(size_t initial_byte_size,
93 size_t minimum_byte_size,
94 size_t maximum_byte_size);
95 void initialize_work();
96 virtual void initialize(ReservedSpace rs, size_t alignment);
97 virtual void initialize_virtual_space(ReservedSpace rs, size_t alignment);
98
99 size_t init_gen_size() { return _init_gen_size; }
100
101 MemRegion reserved() const { return _reserved; }
102
103 bool is_in(const void* p) const {
104 return _virtual_space->contains((void *)p);
105 }
106
107 bool is_in_reserved(const void* p) const {
108 return reserved().contains((void *)p);
109 }
110
111 MutableSpace* eden_space() const { return _eden_space; }
112 MutableSpace* from_space() const { return _from_space; }
113 MutableSpace* to_space() const { return _to_space; }
114 PSVirtualSpace* virtual_space() const { return _virtual_space; }
115
116 // For Adaptive size policy
117 size_t min_gen_size() { return _min_gen_size; }
118
119 // MarkSweep support
120 PSMarkSweepDecorator* eden_mark_sweep() const { return _eden_mark_sweep; }
121 PSMarkSweepDecorator* from_mark_sweep() const { return _from_mark_sweep; }
122 PSMarkSweepDecorator* to_mark_sweep() const { return _to_mark_sweep; }
123
124 void precompact();
125 void adjust_pointers();
126 void compact();
127
128 // Parallel Old
129 void move_and_update(ParCompactionManager* cm);
130
131 // Called during/after gc
132 void swap_spaces();
133
134 // Resize generation using suggested free space size and survivor size
135 // NOTE: "eden_size" and "survivor_size" are suggestions only. Current
136 // heap layout (particularly, live objects in from space) might
137 // not allow us to use these values.
138 void resize(size_t eden_size, size_t survivor_size);
139
140 // Size info
141 size_t capacity_in_bytes() const;
142 size_t used_in_bytes() const;
143 size_t free_in_bytes() const;
144
145 size_t capacity_in_words() const;
146 size_t used_in_words() const;
147 size_t free_in_words() const;
148
149 // The max this generation can grow to
150 size_t max_size() const { return _reserved.byte_size(); }
151
152 // The max this generation can grow to if the boundary between
153 // the generations are allowed to move.
154 size_t gen_size_limit() const { return _max_gen_size; }
155
156 bool is_maximal_no_gc() const {
157 return true; // never expands except at a GC
158 }
159
160 // Allocation
161 HeapWord* allocate(size_t word_size, bool is_tlab) {
162 HeapWord* result = eden_space()->cas_allocate(word_size);
163 return result;
164 }
165
166 HeapWord** top_addr() const { return eden_space()->top_addr(); }
167 HeapWord** end_addr() const { return eden_space()->end_addr(); }
168
169 // Iteration.
170 void oop_iterate(OopClosure* cl);
171 void object_iterate(ObjectClosure* cl);
172
173 virtual void reset_after_change();
174 virtual void reset_survivors_after_shrink();
175
176 // Performance Counter support
177 void update_counters();
178
179 // Debugging - do not use for time critical operations
180 void print() const;
181 void print_on(outputStream* st) const;
182 void print_used_change(size_t prev_used) const;
183 virtual const char* name() const { return "PSYoungGen"; }
184
185 void verify(bool allow_dirty);
186
187 // Space boundary invariant checker
188 void space_invariants() PRODUCT_RETURN;
189
190 // Helper for mangling survivor spaces.
191 void mangle_survivors(MutableSpace* s1,
192 MemRegion s1MR,
193 MutableSpace* s2,
194 MemRegion s2MR) PRODUCT_RETURN;
195
196 void record_spaces_top() PRODUCT_RETURN;
197
198 void try_to_expand_by(size_t expand_bytes);
199 void try_to_shrink_by(size_t shrink_bytes);
200 };