1 /*
2 * Copyright (c) 2011, 2018, 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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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
24
25 #ifndef SHARE_VM_GC_G1_HEAPREGIONSET_HPP
26 #define SHARE_VM_GC_G1_HEAPREGIONSET_HPP
27
28 #include "gc/g1/heapRegion.hpp"
29 #include "utilities/macros.hpp"
30
31 #define assert_heap_region_set(p, message) \
32 do { \
33 assert((p), "[%s] %s ln: %u", \
34 name(), message, length()); \
35 } while (0)
36
37 #define guarantee_heap_region_set(p, message) \
38 do { \
39 guarantee((p), "[%s] %s ln: %u", \
40 name(), message, length()); \
41 } while (0)
42
43 #define assert_free_region_list(p, message) \
44 do { \
45 assert((p), "[%s] %s ln: %u hd: " PTR_FORMAT " tl: " PTR_FORMAT, \
46 name(), message, length(), p2i(_head), p2i(_tail)); \
47 } while (0)
48
49
50 // Interface collecting various instance specific verification methods of
51 // HeapRegionSets.
52 class HeapRegionSetChecker : public CHeapObj<mtGC> {
53 public:
54 // Verify MT safety for this HeapRegionSet.
55 virtual void check_mt_safety() = 0;
56 // Returns true if the given HeapRegion is of the correct type for this HeapRegionSet.
57 virtual bool is_correct_type(HeapRegion* hr) = 0;
58 // Return a description of the type of regions this HeapRegionSet contains.
59 virtual const char* get_description() = 0;
60 };
61
62 // Base class for all the classes that represent heap region sets. It
63 // contains the basic attributes that each set needs to maintain
64 // (e.g., length, region num, used bytes sum) plus any shared
65 // functionality (e.g., verification).
66
67 class HeapRegionSetBase {
68 friend class VMStructs;
69
70 HeapRegionSetChecker* _checker;
71
72 protected:
73 // The number of regions in to the set.
74 uint _length;
75
76 const char* _name;
77
78 bool _verify_in_progress;
79
80 // verify_region() is used to ensure that the contents of a region
81 // added to / removed from a set are consistent.
82 void verify_region(HeapRegion* hr) PRODUCT_RETURN;
83
84 void check_mt_safety() {
85 if (_checker != NULL) {
86 _checker->check_mt_safety();
87 }
88 }
89
90 HeapRegionSetBase(const char* name, HeapRegionSetChecker* verifier);
91
92 public:
93 const char* name() { return _name; }
94
95 uint length() const { return _length; }
96
97 bool is_empty() { return _length == 0; }
98
99 // It updates the fields of the set to reflect hr being added to
100 // the set and tags the region appropriately.
101 inline void add(HeapRegion* hr);
102
103 // It updates the fields of the set to reflect hr being removed
104 // from the set and tags the region appropriately.
105 inline void remove(HeapRegion* hr);
106
107 virtual void verify();
108 void verify_start();
109 void verify_next_region(HeapRegion* hr);
110 void verify_end();
111
112 void verify_optional() { DEBUG_ONLY(verify();) }
113
114 virtual void print_on(outputStream* out, bool print_contents = false);
115 };
116
117 // This class represents heap region sets whose members are not
118 // explicitly tracked. It's helpful to group regions using such sets
119 // so that we can reason about all the region groups in the heap using
120 // the same interface (namely, the HeapRegionSetBase API).
121
122 class HeapRegionSet : public HeapRegionSetBase {
123 public:
124 HeapRegionSet(const char* name, HeapRegionSetChecker* checker):
125 HeapRegionSetBase(name, checker) {
126 }
127
128 void bulk_remove(const uint removed) {
129 _length -= removed;
130 }
131 };
132
133 // A set that links all the regions added to it in a doubly-linked
134 // sorted list. We should try to avoid doing operations that iterate over
135 // such lists in performance critical paths. Typically we should
136 // add / remove one region at a time or concatenate two lists.
137
138 class FreeRegionListIterator;
139
140 class FreeRegionList : public HeapRegionSetBase {
141 friend class FreeRegionListIterator;
142
143 private:
144 HeapRegion* _head;
145 HeapRegion* _tail;
146
147 // _last is used to keep track of where we added an element the last
148 // time. It helps to improve performance when adding several ordered items in a row.
149 HeapRegion* _last;
150
151 static uint _unrealistically_long_length;
152
153 inline HeapRegion* remove_from_head_impl();
154 inline HeapRegion* remove_from_tail_impl();
155
156 protected:
157 // See the comment for HeapRegionSetBase::clear()
158 virtual void clear();
159
160 public:
161 FreeRegionList(const char* name, HeapRegionSetChecker* checker = NULL):
162 HeapRegionSetBase(name, checker) {
163 clear();
164 }
165
166 void verify_list();
167
168 #ifdef ASSERT
169 bool contains(HeapRegion* hr) const {
170 return hr->containing_set() == this;
171 }
172 #endif
173
174 static void set_unrealistically_long_length(uint len);
175
176 // Add hr to the list. The region should not be a member of another set.
177 // Assumes that the list is ordered and will preserve that order. The order
178 // is determined by hrm_index.
179 inline void add_ordered(HeapRegion* hr);
180
181 // Removes from head or tail based on the given argument.
182 HeapRegion* remove_region(bool from_head);
183
184 // Merge two ordered lists. The result is also ordered. The order is
185 // determined by hrm_index.
186 void add_ordered(FreeRegionList* from_list);
187
188 // It empties the list by removing all regions from it.
189 void remove_all();
190
191 // Remove all (contiguous) regions from first to first + num_regions -1 from
192 // this list.
193 // Num_regions must be > 1.
194 void remove_starting_at(HeapRegion* first, uint num_regions);
195
196 virtual void verify();
197 };
198
199 // Iterator class that provides a convenient way to iterate over the
200 // regions of a FreeRegionList.
201
202 class FreeRegionListIterator : public StackObj {
203 private:
204 FreeRegionList* _list;
205 HeapRegion* _curr;
206
207 public:
208 bool more_available() {
209 return _curr != NULL;
210 }
211
212 HeapRegion* get_next() {
213 assert(more_available(),
214 "get_next() should be called when more regions are available");
215
216 // If we are going to introduce a count in the iterator we should
217 // do the "cycle" check.
218
219 HeapRegion* hr = _curr;
220 _list->verify_region(hr);
221 _curr = hr->next();
222 return hr;
223 }
224
225 FreeRegionListIterator(FreeRegionList* list)
226 : _list(list),
227 _curr(list->_head) {
228 }
229 };
230
231 #endif // SHARE_VM_GC_G1_HEAPREGIONSET_HPP