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
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 size_t init_gen_size() { return _init_gen_size; }
98
99 MemRegion reserved() const { return _reserved; }
100
101 bool is_in(const void* p) const {
102 return _virtual_space->contains((void *)p);
103 }
104
105 bool is_in_reserved(const void* p) const {
106 return reserved().contains((void *)p);
107 }
108
109 MutableSpace* eden_space() const { return _eden_space; }
110 MutableSpace* from_space() const { return _from_space; }
111 MutableSpace* to_space() const { return _to_space; }
112 PSVirtualSpace* virtual_space() const { return _virtual_space; }
113
114 // For Adaptive size policy
115 size_t min_gen_size() { return _min_gen_size; }
116
117 // MarkSweep support
118 PSMarkSweepDecorator* eden_mark_sweep() const { return _eden_mark_sweep; }
119 PSMarkSweepDecorator* from_mark_sweep() const { return _from_mark_sweep; }
120 PSMarkSweepDecorator* to_mark_sweep() const { return _to_mark_sweep; }
121
122 void precompact();
123 void adjust_pointers();
124 void compact();
125
126 // Parallel Old
127 void move_and_update(ParCompactionManager* cm);
128
129 // Called during/after gc
130 void swap_spaces();
131
132 // Resize generation using suggested free space size and survivor size
133 // NOTE: "eden_size" and "survivor_size" are suggestions only. Current
134 // heap layout (particularly, live objects in from space) might
135 // not allow us to use these values.
136 void resize(size_t eden_size, size_t survivor_size);
137
138 // Size info
139 size_t capacity_in_bytes() const;
140 size_t used_in_bytes() const;
141 size_t free_in_bytes() const;
142
143 size_t capacity_in_words() const;
144 size_t used_in_words() const;
145 size_t free_in_words() const;
146
147 // The max this generation can grow to
148 size_t max_size() const { return _reserved.byte_size(); }
149
150 // The max this generation can grow to if the boundary between
151 // the generations are allowed to move.
152 size_t gen_size_limit() const { return _max_gen_size; }
153
154 bool is_maximal_no_gc() const {
155 return true; // never expands except at a GC
156 }
157
158 // Allocation
159 HeapWord* allocate(size_t word_size, bool is_tlab) {
160 HeapWord* result = eden_space()->cas_allocate(word_size);
161 return result;
162 }
163
164 HeapWord** top_addr() const { return eden_space()->top_addr(); }
165 HeapWord** end_addr() const { return eden_space()->end_addr(); }
166
167 // Iteration.
168 void oop_iterate(OopClosure* cl);
169 void object_iterate(ObjectClosure* cl);
170
171 virtual void reset_after_change();
172 virtual void reset_survivors_after_shrink();
173
174 // Performance Counter support
175 void update_counters();
176
177 // Debugging - do not use for time critical operations
178 void print() const;
179 void print_on(outputStream* st) const;
180 void print_used_change(size_t prev_used) const;
181 virtual const char* name() const { return "PSYoungGen"; }
182
183 void verify(bool allow_dirty);
184
185 // Space boundary invariant checker
186 void space_invariants() PRODUCT_RETURN;
187
188 // Helper for mangling survivor spaces.
189 void mangle_survivors(MutableSpace* s1,
190 MemRegion s1MR,
191 MutableSpace* s2,
192 MemRegion s2MR) PRODUCT_RETURN;
193
194 void record_spaces_top() PRODUCT_RETURN;
195
196 void try_to_shrink_by(size_t shrink_bytes);
197 };