1 /*
2 * Copyright (c) 2001, 2021, 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
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.
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23 */
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 WorkGang;
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 MutableSpaceMangler;
50
51 class MutableSpace: public CHeapObj<mtGC> {
52 friend class VMStructs;
53
54 // Helper for mangling unused space in debug builds
55 MutableSpaceMangler* _mangler;
56 // The last region which page had been setup to be interleaved.
57 MemRegion _last_setup_region;
58 size_t _alignment;
59 HeapWord* _bottom;
60 HeapWord* volatile _top;
61 HeapWord* _end;
62
63 MutableSpaceMangler* mangler() { return _mangler; }
64
65 void numa_setup_pages(MemRegion mr, bool clear_space);
66
67 void set_last_setup_region(MemRegion mr) { _last_setup_region = mr; }
68 MemRegion last_setup_region() const { return _last_setup_region; }
69
70 template<bool COMPACT_HEADERS>
71 void object_iterate_impl(ObjectClosure* cl);
72
73 public:
74 virtual ~MutableSpace();
75 MutableSpace(size_t page_size);
76
77 // Accessors
78 HeapWord* bottom() const { return _bottom; }
79 HeapWord* top() const { return _top; }
80 HeapWord* end() const { return _end; }
81
82 void set_bottom(HeapWord* value) { _bottom = value; }
83 virtual void set_top(HeapWord* value) { _top = value; }
84 void set_end(HeapWord* value) { _end = value; }
85
86 HeapWord* volatile* top_addr() { return &_top; }
87 HeapWord** end_addr() { return &_end; }
88
89 size_t alignment() { return _alignment; }
90
91 MemRegion region() const { return MemRegion(bottom(), end()); }
92
93 size_t capacity_in_bytes() const { return capacity_in_words() * HeapWordSize; }
94 size_t capacity_in_words() const { return pointer_delta(end(), bottom()); }
95 virtual size_t capacity_in_words(Thread*) const { return capacity_in_words(); }
96
97 // Returns a subregion containing all objects in this space.
98 MemRegion used_region() { return MemRegion(bottom(), top()); }
99
100 static const bool SetupPages = true;
101 static const bool DontSetupPages = false;
102
103 // Initialization
104 virtual void initialize(MemRegion mr,
105 bool clear_space,
106 bool mangle_space,
107 bool setup_pages = SetupPages,
108 WorkGang* pretouch_gang = NULL);
109
110 virtual void clear(bool mangle_space);
111 virtual void update() { }
112 virtual void accumulate_statistics() { }
113
114 // Methods used in mangling. See descriptions under SpaceMangler.
115 virtual void mangle_unused_area() PRODUCT_RETURN;
116 virtual void mangle_unused_area_complete() PRODUCT_RETURN;
117 virtual void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN;
118 virtual void check_mangled_unused_area_complete() PRODUCT_RETURN;
119 virtual void set_top_for_allocations(HeapWord* v) PRODUCT_RETURN;
120
121 // Used to save the space's current top for later use during mangling.
122 virtual void set_top_for_allocations() PRODUCT_RETURN;
123
124 virtual void ensure_parsability() { }
125
126 virtual void mangle_region(MemRegion mr) PRODUCT_RETURN;
127
128 // Boolean queries.
129 bool is_empty() const { return used_in_words() == 0; }
130 bool not_empty() const { return used_in_words() > 0; }
131 bool contains(const void* p) const { return _bottom <= p && p < _end; }
132
133 // Size computations. Sizes are in bytes.
134 size_t used_in_bytes() const { return used_in_words() * HeapWordSize; }
135 size_t free_in_bytes() const { return free_in_words() * HeapWordSize; }
136
137 // Size computations. Sizes are in heapwords.
138 virtual size_t used_in_words() const { return pointer_delta(top(), bottom()); }
139 virtual size_t free_in_words() const { return pointer_delta(end(), top()); }
140 virtual size_t tlab_capacity(Thread* thr) const { return capacity_in_bytes(); }
141 virtual size_t tlab_used(Thread* thr) const { return used_in_bytes(); }
142 virtual size_t unsafe_max_tlab_alloc(Thread* thr) const { return free_in_bytes(); }
143
144 // Allocation (return NULL if full)
145 virtual HeapWord* cas_allocate(size_t word_size);
146 // Optional deallocation. Used in NUMA-allocator.
147 bool cas_deallocate(HeapWord *obj, size_t size);
148 // Return true if this space needs to be expanded in order to satisfy an
149 // allocation request of the indicated size. Concurrent allocations and
150 // resizes may change the result of a later call. Used by oldgen allocator.
151 // precondition: holding ExpandHeap_lock
152 bool needs_expand(size_t word_size) const;
153
154 // Iteration.
155 void oop_iterate(OopIterateClosure* cl);
156 void object_iterate(ObjectClosure* cl);
157
158 // Debugging
159 virtual void print() const;
160 virtual void print_on(outputStream* st) const;
161 virtual void print_short() const;
162 virtual void print_short_on(outputStream* st) const;
163 virtual void verify();
164 };
165
166 #endif // SHARE_GC_PARALLEL_MUTABLESPACE_HPP