1 /*
2 * Copyright (c) 2001, 2023, Oracle and/or its affiliates. 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
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7 * published by the Free Software Foundation.
8 *
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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
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24
25 #ifndef SHARE_GC_PARALLEL_MUTABLESPACE_HPP
26 #define SHARE_GC_PARALLEL_MUTABLESPACE_HPP
27
28 #include "memory/allocation.hpp"
29 #include "memory/iterator.hpp"
30 #include "memory/memRegion.hpp"
31 #include "utilities/copy.hpp"
32 #include "utilities/globalDefinitions.hpp"
33 #include "utilities/macros.hpp"
34
35 class WorkerThreads;
36
37 // A MutableSpace supports the concept of allocation. This includes the
38 // concepts that a space may be only partially full, and the query methods
39 // that go with such an assumption.
40 //
41 // MutableSpace is also responsible for minimizing the
42 // page allocation time by having the memory pretouched (with
43 // AlwaysPretouch) and for optimizing page placement on NUMA systems
44 // by make the underlying region interleaved (with UseNUMA).
45 //
46 // Invariant: bottom() <= top() <= end()
47 // top() and end() are exclusive.
48
49 class MutableSpace: public CHeapObj<mtGC> {
50 friend class VMStructs;
51
52 // The last region which page had been setup to be interleaved.
53 MemRegion _last_setup_region;
54 size_t _alignment;
55 HeapWord* _bottom;
56 HeapWord* volatile _top;
57 HeapWord* _end;
58
59 void numa_setup_pages(MemRegion mr, size_t page_size, bool clear_space);
60
61 void set_last_setup_region(MemRegion mr) { _last_setup_region = mr; }
62 MemRegion last_setup_region() const { return _last_setup_region; }
63
64 public:
65 virtual ~MutableSpace() = default;
66 MutableSpace(size_t page_size);
67
68 // Accessors
69 HeapWord* bottom() const { return _bottom; }
70 HeapWord* top() const { return _top; }
71 HeapWord* end() const { return _end; }
72
73 void set_bottom(HeapWord* value) { _bottom = value; }
74 virtual void set_top(HeapWord* value) { _top = value; }
75 void set_end(HeapWord* value) { _end = value; }
76
77 HeapWord* volatile* top_addr() { return &_top; }
78 HeapWord** end_addr() { return &_end; }
79
80 size_t alignment() { return _alignment; }
81
82 MemRegion region() const { return MemRegion(bottom(), end()); }
83
84 size_t capacity_in_bytes() const { return capacity_in_words() * HeapWordSize; }
85 size_t capacity_in_words() const { return pointer_delta(end(), bottom()); }
86
87 // Returns a subregion containing all objects in this space.
88 MemRegion used_region() { return MemRegion(bottom(), top()); }
89
90 static const bool SetupPages = true;
91 static const bool DontSetupPages = false;
92
93 // Initialization
94 virtual void initialize(MemRegion mr,
95 bool clear_space,
96 bool mangle_space,
97 bool setup_pages = SetupPages,
98 WorkerThreads* pretouch_workers = nullptr);
99
100 virtual void clear(bool mangle_space);
101 virtual void update() { }
102 virtual void accumulate_statistics() { }
103
104 virtual void mangle_unused_area() PRODUCT_RETURN;
105 virtual void mangle_region(MemRegion mr) PRODUCT_RETURN;
106
107 virtual void ensure_parsability() { }
108
109 // Boolean queries.
110 bool is_empty() const { return used_in_words() == 0; }
111 bool not_empty() const { return used_in_words() > 0; }
112 bool contains(const void* p) const { return _bottom <= p && p < _end; }
113
114 // Size computations. Sizes are in bytes.
115 size_t used_in_bytes() const { return used_in_words() * HeapWordSize; }
116 size_t free_in_bytes() const { return free_in_words() * HeapWordSize; }
117
118 // Size computations. Sizes are in heapwords.
119 virtual size_t used_in_words() const { return pointer_delta(top(), bottom()); }
120 virtual size_t free_in_words() const { return pointer_delta(end(), top()); }
121 virtual size_t tlab_capacity(Thread* thr) const { return capacity_in_bytes(); }
122 virtual size_t tlab_used(Thread* thr) const { return used_in_bytes(); }
123 virtual size_t unsafe_max_tlab_alloc(Thread* thr) const { return free_in_bytes(); }
124
125 // Allocation (return null if full)
126 virtual HeapWord* cas_allocate(size_t word_size);
127 // Optional deallocation. Used in NUMA-allocator.
128 bool cas_deallocate(HeapWord *obj, size_t size);
129 // Return true if this space needs to be expanded in order to satisfy an
130 // allocation request of the indicated size. Concurrent allocations and
131 // resizes may change the result of a later call. Used by oldgen allocator.
132 // precondition: holding PSOldGenExpand_lock
133 bool needs_expand(size_t word_size) const;
134
135 // Iteration.
136 void oop_iterate(OopIterateClosure* cl);
137 void object_iterate(ObjectClosure* cl);
138
139 // Debugging
140 virtual void print() const;
141 virtual void print_on(outputStream* st) const;
142 virtual void print_short() const;
143 virtual void print_short_on(outputStream* st) const;
144 virtual void verify();
145 };
146
147 #endif // SHARE_GC_PARALLEL_MUTABLESPACE_HPP