Sat, 23 Nov 2013 12:25:13 +0100
8028128: Add a type safe alternative for working with counter based data
Reviewed-by: dholmes, egahlin
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSYOUNGGEN_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSYOUNGGEN_HPP
28 #include "gc_implementation/parallelScavenge/objectStartArray.hpp"
29 #include "gc_implementation/parallelScavenge/psGenerationCounters.hpp"
30 #include "gc_implementation/parallelScavenge/psVirtualspace.hpp"
31 #include "gc_implementation/shared/mutableSpace.hpp"
32 #include "gc_implementation/shared/spaceCounters.hpp"
34 class PSMarkSweepDecorator;
36 class PSYoungGen : public CHeapObj<mtGC> {
37 friend class VMStructs;
38 friend class ParallelScavengeHeap;
39 friend class AdjoiningGenerations;
41 protected:
42 MemRegion _reserved;
43 PSVirtualSpace* _virtual_space;
45 // Spaces
46 MutableSpace* _eden_space;
47 MutableSpace* _from_space;
48 MutableSpace* _to_space;
51 // MarkSweep Decorators
52 PSMarkSweepDecorator* _eden_mark_sweep;
53 PSMarkSweepDecorator* _from_mark_sweep;
54 PSMarkSweepDecorator* _to_mark_sweep;
56 // Sizing information, in bytes, set in constructor
57 const size_t _init_gen_size;
58 const size_t _min_gen_size;
59 const size_t _max_gen_size;
61 // Performance counters
62 PSGenerationCounters* _gen_counters;
63 SpaceCounters* _eden_counters;
64 SpaceCounters* _from_counters;
65 SpaceCounters* _to_counters;
67 // Initialize the space boundaries
68 void compute_initial_space_boundaries();
70 // Space boundary helper
71 void set_space_boundaries(size_t eden_size, size_t survivor_size);
73 virtual bool resize_generation(size_t eden_size, size_t survivor_size);
74 virtual void resize_spaces(size_t eden_size, size_t survivor_size);
76 // Adjust the spaces to be consistent with the virtual space.
77 void post_resize();
79 // Return number of bytes that the generation can change.
80 // These should not be used by PSYoungGen
81 virtual size_t available_for_expansion();
82 virtual size_t available_for_contraction();
84 // Given a desired shrinkage in the size of the young generation,
85 // return the actual size available for shrinkage.
86 virtual size_t limit_gen_shrink(size_t desired_change);
87 // returns the number of bytes available from the current size
88 // down to the minimum generation size.
89 size_t available_to_min_gen();
90 // Return the number of bytes available for shrinkage considering
91 // the location the live data in the generation.
92 virtual size_t available_to_live();
94 public:
95 // Initialize the generation.
96 PSYoungGen(size_t initial_byte_size,
97 size_t minimum_byte_size,
98 size_t maximum_byte_size);
99 void initialize_work();
100 virtual void initialize(ReservedSpace rs, size_t alignment);
101 virtual void initialize_virtual_space(ReservedSpace rs, size_t alignment);
103 MemRegion reserved() const { return _reserved; }
105 bool is_in(const void* p) const {
106 return _virtual_space->contains((void *)p);
107 }
109 bool is_in_reserved(const void* p) const {
110 return reserved().contains((void *)p);
111 }
113 MutableSpace* eden_space() const { return _eden_space; }
114 MutableSpace* from_space() const { return _from_space; }
115 MutableSpace* to_space() const { return _to_space; }
116 PSVirtualSpace* virtual_space() const { return _virtual_space; }
118 // For Adaptive size policy
119 size_t min_gen_size() { return _min_gen_size; }
121 // MarkSweep support
122 PSMarkSweepDecorator* eden_mark_sweep() const { return _eden_mark_sweep; }
123 PSMarkSweepDecorator* from_mark_sweep() const { return _from_mark_sweep; }
124 PSMarkSweepDecorator* to_mark_sweep() const { return _to_mark_sweep; }
126 void precompact();
127 void adjust_pointers();
128 void compact();
130 // Called during/after gc
131 void swap_spaces();
133 // Resize generation using suggested free space size and survivor size
134 // NOTE: "eden_size" and "survivor_size" are suggestions only. Current
135 // heap layout (particularly, live objects in from space) might
136 // not allow us to use these values.
137 void resize(size_t eden_size, size_t survivor_size);
139 // Size info
140 size_t capacity_in_bytes() const;
141 size_t used_in_bytes() const;
142 size_t free_in_bytes() const;
144 size_t capacity_in_words() const;
145 size_t used_in_words() const;
146 size_t free_in_words() const;
148 // The max this generation can grow to
149 size_t max_size() const { return _reserved.byte_size(); }
151 // The max this generation can grow to if the boundary between
152 // the generations are allowed to move.
153 size_t gen_size_limit() const { return _max_gen_size; }
155 bool is_maximal_no_gc() const {
156 return true; // never expands except at a GC
157 }
159 // Allocation
160 HeapWord* allocate(size_t word_size) {
161 HeapWord* result = eden_space()->cas_allocate(word_size);
162 return result;
163 }
165 HeapWord** top_addr() const { return eden_space()->top_addr(); }
166 HeapWord** end_addr() const { return eden_space()->end_addr(); }
168 // Iteration.
169 void oop_iterate(ExtendedOopClosure* cl);
170 void object_iterate(ObjectClosure* cl);
172 virtual void reset_after_change();
173 virtual void reset_survivors_after_shrink();
175 // Performance Counter support
176 void update_counters();
178 // Debugging - do not use for time critical operations
179 void print() const;
180 void print_on(outputStream* st) const;
181 void print_used_change(size_t prev_used) const;
182 virtual const char* name() const { return "PSYoungGen"; }
184 void verify();
186 // Space boundary invariant checker
187 void space_invariants() PRODUCT_RETURN;
189 // Helper for mangling survivor spaces.
190 void mangle_survivors(MutableSpace* s1,
191 MemRegion s1MR,
192 MutableSpace* s2,
193 MemRegion s2MR) PRODUCT_RETURN;
195 void record_spaces_top() PRODUCT_RETURN;
196 };
198 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSYOUNGGEN_HPP