1 /*
2 * Copyright (c) 2001, 2017, 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.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_MEMORY_BINARYTREEDICTIONARY_HPP
26 #define SHARE_VM_MEMORY_BINARYTREEDICTIONARY_HPP
27
28 #include "memory/freeBlockDictionary.hpp"
29 #include "memory/freeList.hpp"
30
31 /*
32 * A binary tree based search structure for free blocks.
33 * This is currently used in the Concurrent Mark&Sweep implementation, but
34 * will be used for free block management for metadata.
35 */
36
37 // A TreeList is a FreeList which can be used to maintain a
38 // binary tree of free lists.
39
40 template <class Chunk_t, class FreeList_t> class TreeChunk;
41 template <class Chunk_t, class FreeList_t> class BinaryTreeDictionary;
42 template <class Chunk_t, class FreeList_t> class AscendTreeCensusClosure;
43 template <class Chunk_t, class FreeList_t> class DescendTreeCensusClosure;
44 template <class Chunk_t, class FreeList_t> class DescendTreeSearchClosure;
45
46 class FreeChunk;
47 template <class> class AdaptiveFreeList;
48 typedef BinaryTreeDictionary<FreeChunk, AdaptiveFreeList<FreeChunk> > AFLBinaryTreeDictionary;
49
50 template <class Chunk_t, class FreeList_t>
51 class TreeList : public FreeList_t {
52 friend class TreeChunk<Chunk_t, FreeList_t>;
53 friend class BinaryTreeDictionary<Chunk_t, FreeList_t>;
54 friend class AscendTreeCensusClosure<Chunk_t, FreeList_t>;
55 friend class DescendTreeCensusClosure<Chunk_t, FreeList_t>;
56 friend class DescendTreeSearchClosure<Chunk_t, FreeList_t>;
57
58 TreeList<Chunk_t, FreeList_t>* _parent;
59 TreeList<Chunk_t, FreeList_t>* _left;
60 TreeList<Chunk_t, FreeList_t>* _right;
61
62 protected:
63
64 TreeList<Chunk_t, FreeList_t>* parent() const { return _parent; }
65 TreeList<Chunk_t, FreeList_t>* left() const { return _left; }
66 TreeList<Chunk_t, FreeList_t>* right() const { return _right; }
67
68 // Wrapper on call to base class, to get the template to compile.
69 Chunk_t* head() const { return FreeList_t::head(); }
70 Chunk_t* tail() const { return FreeList_t::tail(); }
71 void set_head(Chunk_t* head) { FreeList_t::set_head(head); }
72 void set_tail(Chunk_t* tail) { FreeList_t::set_tail(tail); }
73
74 size_t size() const { return FreeList_t::size(); }
75
76 // Accessors for links in tree.
77
78 void set_left(TreeList<Chunk_t, FreeList_t>* tl) {
79 _left = tl;
80 if (tl != NULL)
81 tl->set_parent(this);
82 }
83 void set_right(TreeList<Chunk_t, FreeList_t>* tl) {
84 _right = tl;
85 if (tl != NULL)
86 tl->set_parent(this);
87 }
88 void set_parent(TreeList<Chunk_t, FreeList_t>* tl) { _parent = tl; }
89
90 void clear_left() { _left = NULL; }
91 void clear_right() { _right = NULL; }
92 void clear_parent() { _parent = NULL; }
93 void initialize() { clear_left(); clear_right(), clear_parent(); FreeList_t::initialize(); }
94
95 // For constructing a TreeList from a Tree chunk or
96 // address and size.
97 TreeList();
98 static TreeList<Chunk_t, FreeList_t>*
99 as_TreeList(TreeChunk<Chunk_t, FreeList_t>* tc);
100 static TreeList<Chunk_t, FreeList_t>* as_TreeList(HeapWord* addr, size_t size);
101
102 // Returns the head of the free list as a pointer to a TreeChunk.
103 TreeChunk<Chunk_t, FreeList_t>* head_as_TreeChunk();
104
105 // Returns the first available chunk in the free list as a pointer
106 // to a TreeChunk.
107 TreeChunk<Chunk_t, FreeList_t>* first_available();
108
109 // Returns the block with the largest heap address amongst
110 // those in the list for this size; potentially slow and expensive,
111 // use with caution!
112 TreeChunk<Chunk_t, FreeList_t>* largest_address();
113
114 TreeList<Chunk_t, FreeList_t>* get_better_list(
115 BinaryTreeDictionary<Chunk_t, FreeList_t>* dictionary);
116
117 // remove_chunk_replace_if_needed() removes the given "tc" from the TreeList.
118 // If "tc" is the first chunk in the list, it is also the
119 // TreeList that is the node in the tree. remove_chunk_replace_if_needed()
120 // returns the possibly replaced TreeList* for the node in
121 // the tree. It also updates the parent of the original
122 // node to point to the new node.
123 TreeList<Chunk_t, FreeList_t>* remove_chunk_replace_if_needed(TreeChunk<Chunk_t, FreeList_t>* tc);
124 // See FreeList.
125 void return_chunk_at_head(TreeChunk<Chunk_t, FreeList_t>* tc);
126 void return_chunk_at_tail(TreeChunk<Chunk_t, FreeList_t>* tc);
127 };
128
129 // A TreeChunk is a subclass of a Chunk that additionally
130 // maintains a pointer to the free list on which it is currently
131 // linked.
132 // A TreeChunk is also used as a node in the binary tree. This
133 // allows the binary tree to be maintained without any additional
134 // storage (the free chunks are used). In a binary tree the first
135 // chunk in the free list is also the tree node. Note that the
136 // TreeChunk has an embedded TreeList for this purpose. Because
137 // the first chunk in the list is distinguished in this fashion
138 // (also is the node in the tree), it is the last chunk to be found
139 // on the free list for a node in the tree and is only removed if
140 // it is the last chunk on the free list.
141
142 template <class Chunk_t, class FreeList_t>
143 class TreeChunk : public Chunk_t {
144 friend class TreeList<Chunk_t, FreeList_t>;
145 TreeList<Chunk_t, FreeList_t>* _list;
146 TreeList<Chunk_t, FreeList_t> _embedded_list; // if non-null, this chunk is on _list
147
148 static size_t _min_tree_chunk_size;
149
150 protected:
151 TreeList<Chunk_t, FreeList_t>* embedded_list() const { return (TreeList<Chunk_t, FreeList_t>*) &_embedded_list; }
152 void set_embedded_list(TreeList<Chunk_t, FreeList_t>* v) { _embedded_list = *v; }
153 public:
154 TreeList<Chunk_t, FreeList_t>* list() { return _list; }
155 void set_list(TreeList<Chunk_t, FreeList_t>* v) { _list = v; }
156 static TreeChunk<Chunk_t, FreeList_t>* as_TreeChunk(Chunk_t* fc);
157 // Initialize fields in a TreeChunk that should be
158 // initialized when the TreeChunk is being added to
159 // a free list in the tree.
160 void initialize() { embedded_list()->initialize(); }
161
162 Chunk_t* next() const { return Chunk_t::next(); }
163 Chunk_t* prev() const { return Chunk_t::prev(); }
164 size_t size() const volatile { return Chunk_t::size(); }
165
166 static size_t min_size();
167
168 // debugging
169 void verify_tree_chunk_list() const;
170 void assert_is_mangled() const;
171 };
172
173 template <class Chunk_t, class FreeList_t>
174 size_t TreeChunk<Chunk_t, FreeList_t>::_min_tree_chunk_size = sizeof(TreeChunk<Chunk_t, FreeList_t>)/HeapWordSize;
175 template <class Chunk_t, class FreeList_t>
176 size_t TreeChunk<Chunk_t, FreeList_t>::min_size() { return _min_tree_chunk_size; }
177
178 template <class Chunk_t, class FreeList_t>
179 class BinaryTreeDictionary: public FreeBlockDictionary<Chunk_t> {
180 friend class VMStructs;
181 size_t _total_size;
182 size_t _total_free_blocks;
183 TreeList<Chunk_t, FreeList_t>* _root;
184
185 // private accessors
186 void set_total_size(size_t v) { _total_size = v; }
187 virtual void inc_total_size(size_t v);
188 virtual void dec_total_size(size_t v);
189 void set_total_free_blocks(size_t v) { _total_free_blocks = v; }
190 TreeList<Chunk_t, FreeList_t>* root() const { return _root; }
191 void set_root(TreeList<Chunk_t, FreeList_t>* v) { _root = v; }
192
193 // This field is added and can be set to point to the
194 // the Mutex used to synchronize access to the
195 // dictionary so that assertion checking can be done.
196 // For example it is set to point to _parDictionaryAllocLock.
197 NOT_PRODUCT(Mutex* _lock;)
198
199 // Remove a chunk of size "size" or larger from the tree and
200 // return it. If the chunk
201 // is the last chunk of that size, remove the node for that size
202 // from the tree.
203 TreeChunk<Chunk_t, FreeList_t>* get_chunk_from_tree(size_t size, enum FreeBlockDictionary<Chunk_t>::Dither dither);
204 // Remove this chunk from the tree. If the removal results
205 // in an empty list in the tree, remove the empty list.
206 TreeChunk<Chunk_t, FreeList_t>* remove_chunk_from_tree(TreeChunk<Chunk_t, FreeList_t>* tc);
207 // Remove the node in the trees starting at tl that has the
208 // minimum value and return it. Repair the tree as needed.
209 TreeList<Chunk_t, FreeList_t>* remove_tree_minimum(TreeList<Chunk_t, FreeList_t>* tl);
210 // Add this free chunk to the tree.
211 void insert_chunk_in_tree(Chunk_t* freeChunk);
212 public:
213
214 // Return a list of the specified size or NULL from the tree.
215 // The list is not removed from the tree.
216 TreeList<Chunk_t, FreeList_t>* find_list (size_t size) const;
217
218 void verify_tree() const;
219 // verify that the given chunk is in the tree.
220 bool verify_chunk_in_free_list(Chunk_t* tc) const;
221 private:
222 void verify_tree_helper(TreeList<Chunk_t, FreeList_t>* tl) const;
223 static size_t verify_prev_free_ptrs(TreeList<Chunk_t, FreeList_t>* tl);
224
225 // Returns the total number of chunks in the list.
226 size_t total_list_length(TreeList<Chunk_t, FreeList_t>* tl) const;
227 // Returns the total number of words in the chunks in the tree
228 // starting at "tl".
229 size_t total_size_in_tree(TreeList<Chunk_t, FreeList_t>* tl) const;
230 // Returns the sum of the square of the size of each block
231 // in the tree starting at "tl".
232 double sum_of_squared_block_sizes(TreeList<Chunk_t, FreeList_t>* const tl) const;
233 // Returns the total number of free blocks in the tree starting
234 // at "tl".
235 size_t total_free_blocks_in_tree(TreeList<Chunk_t, FreeList_t>* tl) const;
236 size_t num_free_blocks() const;
237 size_t tree_height() const;
238 size_t tree_height_helper(TreeList<Chunk_t, FreeList_t>* tl) const;
239 size_t total_nodes_in_tree(TreeList<Chunk_t, FreeList_t>* tl) const;
240 size_t total_nodes_helper(TreeList<Chunk_t, FreeList_t>* tl) const;
241
242 public:
243 // Constructor
244 BinaryTreeDictionary() :
245 _total_size(0), _total_free_blocks(0), _root(0) {}
246
247 BinaryTreeDictionary(MemRegion mr);
248
249 // Public accessors
250 size_t total_size() const { return _total_size; }
251 size_t total_free_blocks() const { return _total_free_blocks; }
252
253 // Reset the dictionary to the initial conditions with
254 // a single free chunk.
255 void reset(MemRegion mr);
256 void reset(HeapWord* addr, size_t size);
257 // Reset the dictionary to be empty.
258 void reset();
259
260 // Return a chunk of size "size" or greater from
261 // the tree.
262 Chunk_t* get_chunk(size_t size, enum FreeBlockDictionary<Chunk_t>::Dither dither) {
263 FreeBlockDictionary<Chunk_t>::verify_par_locked();
264 Chunk_t* res = get_chunk_from_tree(size, dither);
265 assert(res == NULL || res->is_free(),
266 "Should be returning a free chunk");
267 assert(dither != FreeBlockDictionary<Chunk_t>::exactly ||
268 res == NULL || res->size() == size, "Not correct size");
269 return res;
270 }
271
272 void return_chunk(Chunk_t* chunk) {
273 FreeBlockDictionary<Chunk_t>::verify_par_locked();
274 insert_chunk_in_tree(chunk);
275 }
276
277 void remove_chunk(Chunk_t* chunk) {
278 FreeBlockDictionary<Chunk_t>::verify_par_locked();
279 remove_chunk_from_tree((TreeChunk<Chunk_t, FreeList_t>*)chunk);
280 assert(chunk->is_free(), "Should still be a free chunk");
281 }
282
283 size_t max_chunk_size() const;
284 size_t total_chunk_size(debug_only(const Mutex* lock)) const {
285 debug_only(
286 if (lock != NULL && lock->owned_by_self()) {
287 assert(total_size_in_tree(root()) == total_size(),
288 "_total_size inconsistency");
289 }
290 )
291 return total_size();
292 }
293
294 size_t min_size() const {
295 return TreeChunk<Chunk_t, FreeList_t>::min_size();
296 }
297
298 double sum_of_squared_block_sizes() const {
299 return sum_of_squared_block_sizes(root());
300 }
301
302 Chunk_t* find_chunk_ends_at(HeapWord* target) const;
303
304 // Find the list with size "size" in the binary tree and update
305 // the statistics in the list according to "split" (chunk was
306 // split or coalesce) and "birth" (chunk was added or removed).
307 void dict_census_update(size_t size, bool split, bool birth);
308 // Return true if the dictionary is overpopulated (more chunks of
309 // this size than desired) for size "size".
310 bool coal_dict_over_populated(size_t size);
311 // Methods called at the beginning of a sweep to prepare the
312 // statistics for the sweep.
313 void begin_sweep_dict_census(double coalSurplusPercent,
314 float inter_sweep_current,
315 float inter_sweep_estimate,
316 float intra_sweep_estimate);
317 // Methods called after the end of a sweep to modify the
318 // statistics for the sweep.
319 void end_sweep_dict_census(double splitSurplusPercent);
320 // Return the largest free chunk in the tree.
321 Chunk_t* find_largest_dict() const;
322 // Accessors for statistics
323 void set_tree_surplus(double splitSurplusPercent);
324 void set_tree_hints(void);
325 // Reset statistics for all the lists in the tree.
326 void clear_tree_census(void);
327 // Print the statistics for all the lists in the tree. Also may
328 // print out summaries.
329 void print_dict_census(outputStream* st) const;
330 void print_free_lists(outputStream* st) const;
331
332 // For debugging. Returns the sum of the _returned_bytes for
333 // all lists in the tree.
334 size_t sum_dict_returned_bytes() PRODUCT_RETURN0;
335 // Sets the _returned_bytes for all the lists in the tree to zero.
336 void initialize_dict_returned_bytes() PRODUCT_RETURN;
337 // For debugging. Return the total number of chunks in the dictionary.
338 size_t total_count() PRODUCT_RETURN0;
339
340 void report_statistics(outputStream* st) const;
341
342 void verify() const;
343 };
344
345 #endif // SHARE_VM_MEMORY_BINARYTREEDICTIONARY_HPP