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 private:
145 friend class TreeList<Chunk_t, FreeList_t>;
146 TreeList<Chunk_t, FreeList_t>* _list;
147 TreeList<Chunk_t, FreeList_t> _embedded_list; // if non-null, this chunk is on _list
148
149 static size_t _min_tree_chunk_size;
150
151 protected:
152 TreeList<Chunk_t, FreeList_t>* embedded_list() const { return (TreeList<Chunk_t, FreeList_t>*) &_embedded_list; }
153 void set_embedded_list(TreeList<Chunk_t, FreeList_t>* v) { _embedded_list = *v; }
154 public:
155 TreeList<Chunk_t, FreeList_t>* list() { return _list; }
156 void set_list(TreeList<Chunk_t, FreeList_t>* v) { _list = v; }
157 static TreeChunk<Chunk_t, FreeList_t>* as_TreeChunk(Chunk_t* fc);
158 // Initialize fields in a TreeChunk that should be
159 // initialized when the TreeChunk is being added to
160 // a free list in the tree.
161 void initialize() { embedded_list()->initialize(); }
162
163 Chunk_t* next() const { return Chunk_t::next(); }
164 Chunk_t* prev() const { return Chunk_t::prev(); }
165 size_t size() const volatile { return Chunk_t::size(); }
166
167 static size_t min_size();
168
169 // debugging
170 void verify_tree_chunk_list() const;
171 void assert_is_mangled() const;
172 };
173
174 template <class Chunk_t, class FreeList_t>
175 size_t TreeChunk<Chunk_t, FreeList_t>::_min_tree_chunk_size = sizeof(TreeChunk<Chunk_t, FreeList_t>)/HeapWordSize;
176 template <class Chunk_t, class FreeList_t>
177 size_t TreeChunk<Chunk_t, FreeList_t>::min_size() { return _min_tree_chunk_size; }
178
179 template <class Chunk_t, class FreeList_t>
180 class BinaryTreeDictionary: public FreeBlockDictionary<Chunk_t> {
181 friend class VMStructs;
182 size_t _total_size;
183 size_t _total_free_blocks;
184 TreeList<Chunk_t, FreeList_t>* _root;
185
186 // private accessors
187 void set_total_size(size_t v) { _total_size = v; }
188 virtual void inc_total_size(size_t v);
189 virtual void dec_total_size(size_t v);
190 void set_total_free_blocks(size_t v) { _total_free_blocks = v; }
191 TreeList<Chunk_t, FreeList_t>* root() const { return _root; }
192 void set_root(TreeList<Chunk_t, FreeList_t>* v) { _root = v; }
193
194 // This field is added and can be set to point to the
195 // the Mutex used to synchronize access to the
196 // dictionary so that assertion checking can be done.
197 // For example it is set to point to _parDictionaryAllocLock.
198 NOT_PRODUCT(Mutex* _lock;)
199
200 // Remove a chunk of size "size" or larger from the tree and
201 // return it. If the chunk
202 // is the last chunk of that size, remove the node for that size
203 // from the tree.
204 TreeChunk<Chunk_t, FreeList_t>* get_chunk_from_tree(size_t size, enum FreeBlockDictionary<Chunk_t>::Dither dither);
205 // Remove this chunk from the tree. If the removal results
206 // in an empty list in the tree, remove the empty list.
207 TreeChunk<Chunk_t, FreeList_t>* remove_chunk_from_tree(TreeChunk<Chunk_t, FreeList_t>* tc);
208 // Remove the node in the trees starting at tl that has the
209 // minimum value and return it. Repair the tree as needed.
210 TreeList<Chunk_t, FreeList_t>* remove_tree_minimum(TreeList<Chunk_t, FreeList_t>* tl);
211 // Add this free chunk to the tree.
212 void insert_chunk_in_tree(Chunk_t* freeChunk);
213 public:
214
215 // Return a list of the specified size or NULL from the tree.
216 // The list is not removed from the tree.
217 TreeList<Chunk_t, FreeList_t>* find_list (size_t size) const;
218
219 void verify_tree() const;
220 // verify that the given chunk is in the tree.
221 bool verify_chunk_in_free_list(Chunk_t* tc) const;
222 private:
223 void verify_tree_helper(TreeList<Chunk_t, FreeList_t>* tl) const;
224 static size_t verify_prev_free_ptrs(TreeList<Chunk_t, FreeList_t>* tl);
225
226 // Returns the total number of chunks in the list.
227 size_t total_list_length(TreeList<Chunk_t, FreeList_t>* tl) const;
228 // Returns the total number of words in the chunks in the tree
229 // starting at "tl".
230 size_t total_size_in_tree(TreeList<Chunk_t, FreeList_t>* tl) const;
231 // Returns the sum of the square of the size of each block
232 // in the tree starting at "tl".
233 double sum_of_squared_block_sizes(TreeList<Chunk_t, FreeList_t>* const tl) const;
234 // Returns the total number of free blocks in the tree starting
235 // at "tl".
236 size_t total_free_blocks_in_tree(TreeList<Chunk_t, FreeList_t>* tl) const;
237 size_t num_free_blocks() const;
238 size_t tree_height() const;
239 size_t tree_height_helper(TreeList<Chunk_t, FreeList_t>* tl) const;
240 size_t total_nodes_in_tree(TreeList<Chunk_t, FreeList_t>* tl) const;
241 size_t total_nodes_helper(TreeList<Chunk_t, FreeList_t>* tl) const;
242
243 public:
244 // Constructor
245 BinaryTreeDictionary() :
246 _total_size(0), _total_free_blocks(0), _root(0) {}
247
248 BinaryTreeDictionary(MemRegion mr);
249
250 // Public accessors
251 size_t total_size() const { return _total_size; }
252 size_t total_free_blocks() const { return _total_free_blocks; }
253
254 // Reset the dictionary to the initial conditions with
255 // a single free chunk.
256 void reset(MemRegion mr);
257 void reset(HeapWord* addr, size_t size);
258 // Reset the dictionary to be empty.
259 void reset();
260
261 // Return a chunk of size "size" or greater from
262 // the tree.
263 Chunk_t* get_chunk(size_t size, enum FreeBlockDictionary<Chunk_t>::Dither dither) {
264 FreeBlockDictionary<Chunk_t>::verify_par_locked();
265 Chunk_t* res = get_chunk_from_tree(size, dither);
266 assert(res == NULL || res->is_free(),
267 "Should be returning a free chunk");
268 assert(dither != FreeBlockDictionary<Chunk_t>::exactly ||
269 res == NULL || res->size() == size, "Not correct size");
270 return res;
271 }
272
273 void return_chunk(Chunk_t* chunk) {
274 FreeBlockDictionary<Chunk_t>::verify_par_locked();
275 insert_chunk_in_tree(chunk);
276 }
277
278 void remove_chunk(Chunk_t* chunk) {
279 FreeBlockDictionary<Chunk_t>::verify_par_locked();
280 remove_chunk_from_tree((TreeChunk<Chunk_t, FreeList_t>*)chunk);
281 assert(chunk->is_free(), "Should still be a free chunk");
282 }
283
284 size_t max_chunk_size() const;
285 size_t total_chunk_size(debug_only(const Mutex* lock)) const {
286 debug_only(
287 if (lock != NULL && lock->owned_by_self()) {
288 assert(total_size_in_tree(root()) == total_size(),
289 "_total_size inconsistency");
290 }
291 )
292 return total_size();
293 }
294
295 size_t min_size() const {
296 return TreeChunk<Chunk_t, FreeList_t>::min_size();
297 }
298
299 double sum_of_squared_block_sizes() const {
300 return sum_of_squared_block_sizes(root());
301 }
302
303 Chunk_t* find_chunk_ends_at(HeapWord* target) const;
304
305 // Find the list with size "size" in the binary tree and update
306 // the statistics in the list according to "split" (chunk was
307 // split or coalesce) and "birth" (chunk was added or removed).
308 void dict_census_update(size_t size, bool split, bool birth);
309 // Return true if the dictionary is overpopulated (more chunks of
310 // this size than desired) for size "size".
311 bool coal_dict_over_populated(size_t size);
312 // Methods called at the beginning of a sweep to prepare the
313 // statistics for the sweep.
314 void begin_sweep_dict_census(double coalSurplusPercent,
315 float inter_sweep_current,
316 float inter_sweep_estimate,
317 float intra_sweep_estimate);
318 // Methods called after the end of a sweep to modify the
319 // statistics for the sweep.
320 void end_sweep_dict_census(double splitSurplusPercent);
321 // Return the largest free chunk in the tree.
322 Chunk_t* find_largest_dict() const;
323 // Accessors for statistics
324 void set_tree_surplus(double splitSurplusPercent);
325 void set_tree_hints(void);
326 // Reset statistics for all the lists in the tree.
327 void clear_tree_census(void);
328 // Print the statistics for all the lists in the tree. Also may
329 // print out summaries.
330 void print_dict_census(outputStream* st) const;
331 void print_free_lists(outputStream* st) const;
332
333 // For debugging. Returns the sum of the _returned_bytes for
334 // all lists in the tree.
335 size_t sum_dict_returned_bytes() PRODUCT_RETURN0;
336 // Sets the _returned_bytes for all the lists in the tree to zero.
337 void initialize_dict_returned_bytes() PRODUCT_RETURN;
338 // For debugging. Return the total number of chunks in the dictionary.
339 size_t total_count() PRODUCT_RETURN0;
340
341 void report_statistics(outputStream* st) const;
342
343 void verify() const;
344 };
345
346 #endif // SHARE_VM_MEMORY_BINARYTREEDICTIONARY_HPP