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7131629: Generalize the CMS free list code Summary: Make the FreeChunk, FreeList, TreeList, and BinaryTreeDictionary classes usable outside CMS. Reviewed-by: brutisso, johnc, jwilhelm Contributed-by: coleen.phillimore@oracle.com
author jmasa
date Thu, 29 Mar 2012 19:46:24 -0700
parents src/share/vm/gc_implementation/concurrentMarkSweep/binaryTreeDictionary.hpp@f95d63e2154a
children f69a5d43dc19
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6016:3c91f2c9fd21 6026:9f059abe8cf2
1 /*
2 * Copyright (c) 2001, 2012, 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> class TreeChunk;
41 template <class Chunk> class BinaryTreeDictionary;
42 template <class Chunk> class AscendTreeCensusClosure;
43 template <class Chunk> class DescendTreeCensusClosure;
44 template <class Chunk> class DescendTreeSearchClosure;
45
46 template <class Chunk>
47 class TreeList: public FreeList<Chunk> {
48 friend class TreeChunk<Chunk>;
49 friend class BinaryTreeDictionary<Chunk>;
50 friend class AscendTreeCensusClosure<Chunk>;
51 friend class DescendTreeCensusClosure<Chunk>;
52 friend class DescendTreeSearchClosure<Chunk>;
53
54 TreeList<Chunk>* _parent;
55 TreeList<Chunk>* _left;
56 TreeList<Chunk>* _right;
57
58 protected:
59 TreeList<Chunk>* parent() const { return _parent; }
60 TreeList<Chunk>* left() const { return _left; }
61 TreeList<Chunk>* right() const { return _right; }
62
63 // Wrapper on call to base class, to get the template to compile.
64 Chunk* head() const { return FreeList<Chunk>::head(); }
65 Chunk* tail() const { return FreeList<Chunk>::tail(); }
66 void set_head(Chunk* head) { FreeList<Chunk>::set_head(head); }
67 void set_tail(Chunk* tail) { FreeList<Chunk>::set_tail(tail); }
68
69 size_t size() const { return FreeList<Chunk>::size(); }
70
71 // Accessors for links in tree.
72
73 void setLeft(TreeList<Chunk>* tl) {
74 _left = tl;
75 if (tl != NULL)
76 tl->setParent(this);
77 }
78 void setRight(TreeList<Chunk>* tl) {
79 _right = tl;
80 if (tl != NULL)
81 tl->setParent(this);
82 }
83 void setParent(TreeList<Chunk>* tl) { _parent = tl; }
84
85 void clearLeft() { _left = NULL; }
86 void clearRight() { _right = NULL; }
87 void clearParent() { _parent = NULL; }
88 void initialize() { clearLeft(); clearRight(), clearParent(); }
89
90 // For constructing a TreeList from a Tree chunk or
91 // address and size.
92 static TreeList<Chunk>* as_TreeList(TreeChunk<Chunk>* tc);
93 static TreeList<Chunk>* as_TreeList(HeapWord* addr, size_t size);
94
95 // Returns the head of the free list as a pointer to a TreeChunk.
96 TreeChunk<Chunk>* head_as_TreeChunk();
97
98 // Returns the first available chunk in the free list as a pointer
99 // to a TreeChunk.
100 TreeChunk<Chunk>* first_available();
101
102 // Returns the block with the largest heap address amongst
103 // those in the list for this size; potentially slow and expensive,
104 // use with caution!
105 TreeChunk<Chunk>* largest_address();
106
107 // removeChunkReplaceIfNeeded() removes the given "tc" from the TreeList.
108 // If "tc" is the first chunk in the list, it is also the
109 // TreeList that is the node in the tree. removeChunkReplaceIfNeeded()
110 // returns the possibly replaced TreeList* for the node in
111 // the tree. It also updates the parent of the original
112 // node to point to the new node.
113 TreeList<Chunk>* removeChunkReplaceIfNeeded(TreeChunk<Chunk>* tc);
114 // See FreeList.
115 void returnChunkAtHead(TreeChunk<Chunk>* tc);
116 void returnChunkAtTail(TreeChunk<Chunk>* tc);
117 };
118
119 // A TreeChunk is a subclass of a Chunk that additionally
120 // maintains a pointer to the free list on which it is currently
121 // linked.
122 // A TreeChunk is also used as a node in the binary tree. This
123 // allows the binary tree to be maintained without any additional
124 // storage (the free chunks are used). In a binary tree the first
125 // chunk in the free list is also the tree node. Note that the
126 // TreeChunk has an embedded TreeList for this purpose. Because
127 // the first chunk in the list is distinguished in this fashion
128 // (also is the node in the tree), it is the last chunk to be found
129 // on the free list for a node in the tree and is only removed if
130 // it is the last chunk on the free list.
131
132 template <class Chunk>
133 class TreeChunk : public Chunk {
134 friend class TreeList<Chunk>;
135 TreeList<Chunk>* _list;
136 TreeList<Chunk> _embedded_list; // if non-null, this chunk is on _list
137 protected:
138 TreeList<Chunk>* embedded_list() const { return (TreeList<Chunk>*) &_embedded_list; }
139 void set_embedded_list(TreeList<Chunk>* v) { _embedded_list = *v; }
140 public:
141 TreeList<Chunk>* list() { return _list; }
142 void set_list(TreeList<Chunk>* v) { _list = v; }
143 static TreeChunk<Chunk>* as_TreeChunk(Chunk* fc);
144 // Initialize fields in a TreeChunk that should be
145 // initialized when the TreeChunk is being added to
146 // a free list in the tree.
147 void initialize() { embedded_list()->initialize(); }
148
149 Chunk* next() const { return Chunk::next(); }
150 Chunk* prev() const { return Chunk::prev(); }
151 size_t size() const volatile { return Chunk::size(); }
152
153 // debugging
154 void verifyTreeChunkList() const;
155 };
156
157
158 template <class Chunk>
159 class BinaryTreeDictionary: public FreeBlockDictionary<Chunk> {
160 friend class VMStructs;
161 bool _splay;
162 size_t _totalSize;
163 size_t _totalFreeBlocks;
164 TreeList<Chunk>* _root;
165 bool _adaptive_freelists;
166
167 // private accessors
168 bool splay() const { return _splay; }
169 void set_splay(bool v) { _splay = v; }
170 void set_totalSize(size_t v) { _totalSize = v; }
171 virtual void inc_totalSize(size_t v);
172 virtual void dec_totalSize(size_t v);
173 size_t totalFreeBlocks() const { return _totalFreeBlocks; }
174 void set_totalFreeBlocks(size_t v) { _totalFreeBlocks = v; }
175 TreeList<Chunk>* root() const { return _root; }
176 void set_root(TreeList<Chunk>* v) { _root = v; }
177 bool adaptive_freelists() { return _adaptive_freelists; }
178
179 // This field is added and can be set to point to the
180 // the Mutex used to synchronize access to the
181 // dictionary so that assertion checking can be done.
182 // For example it is set to point to _parDictionaryAllocLock.
183 NOT_PRODUCT(Mutex* _lock;)
184
185 // Remove a chunk of size "size" or larger from the tree and
186 // return it. If the chunk
187 // is the last chunk of that size, remove the node for that size
188 // from the tree.
189 TreeChunk<Chunk>* getChunkFromTree(size_t size, enum FreeBlockDictionary<Chunk>::Dither dither, bool splay);
190 // Return a list of the specified size or NULL from the tree.
191 // The list is not removed from the tree.
192 TreeList<Chunk>* findList (size_t size) const;
193 // Remove this chunk from the tree. If the removal results
194 // in an empty list in the tree, remove the empty list.
195 TreeChunk<Chunk>* removeChunkFromTree(TreeChunk<Chunk>* tc);
196 // Remove the node in the trees starting at tl that has the
197 // minimum value and return it. Repair the tree as needed.
198 TreeList<Chunk>* removeTreeMinimum(TreeList<Chunk>* tl);
199 void semiSplayStep(TreeList<Chunk>* tl);
200 // Add this free chunk to the tree.
201 void insertChunkInTree(Chunk* freeChunk);
202 public:
203
204 static const size_t min_tree_chunk_size = sizeof(TreeChunk<Chunk>)/HeapWordSize;
205
206 void verifyTree() const;
207 // verify that the given chunk is in the tree.
208 bool verifyChunkInFreeLists(Chunk* tc) const;
209 private:
210 void verifyTreeHelper(TreeList<Chunk>* tl) const;
211 static size_t verifyPrevFreePtrs(TreeList<Chunk>* tl);
212
213 // Returns the total number of chunks in the list.
214 size_t totalListLength(TreeList<Chunk>* tl) const;
215 // Returns the total number of words in the chunks in the tree
216 // starting at "tl".
217 size_t totalSizeInTree(TreeList<Chunk>* tl) const;
218 // Returns the sum of the square of the size of each block
219 // in the tree starting at "tl".
220 double sum_of_squared_block_sizes(TreeList<Chunk>* const tl) const;
221 // Returns the total number of free blocks in the tree starting
222 // at "tl".
223 size_t totalFreeBlocksInTree(TreeList<Chunk>* tl) const;
224 size_t numFreeBlocks() const;
225 size_t treeHeight() const;
226 size_t treeHeightHelper(TreeList<Chunk>* tl) const;
227 size_t totalNodesInTree(TreeList<Chunk>* tl) const;
228 size_t totalNodesHelper(TreeList<Chunk>* tl) const;
229
230 public:
231 // Constructor
232 BinaryTreeDictionary(bool adaptive_freelists, bool splay = false);
233 BinaryTreeDictionary(MemRegion mr, bool adaptive_freelists, bool splay = false);
234
235 // Public accessors
236 size_t totalSize() const { return _totalSize; }
237
238 // Reset the dictionary to the initial conditions with
239 // a single free chunk.
240 void reset(MemRegion mr);
241 void reset(HeapWord* addr, size_t size);
242 // Reset the dictionary to be empty.
243 void reset();
244
245 // Return a chunk of size "size" or greater from
246 // the tree.
247 // want a better dynamic splay strategy for the future.
248 Chunk* getChunk(size_t size, enum FreeBlockDictionary<Chunk>::Dither dither) {
249 FreeBlockDictionary<Chunk>::verify_par_locked();
250 Chunk* res = getChunkFromTree(size, dither, splay());
251 assert(res == NULL || res->isFree(),
252 "Should be returning a free chunk");
253 return res;
254 }
255
256 void returnChunk(Chunk* chunk) {
257 FreeBlockDictionary<Chunk>::verify_par_locked();
258 insertChunkInTree(chunk);
259 }
260
261 void removeChunk(Chunk* chunk) {
262 FreeBlockDictionary<Chunk>::verify_par_locked();
263 removeChunkFromTree((TreeChunk<Chunk>*)chunk);
264 assert(chunk->isFree(), "Should still be a free chunk");
265 }
266
267 size_t maxChunkSize() const;
268 size_t totalChunkSize(debug_only(const Mutex* lock)) const {
269 debug_only(
270 if (lock != NULL && lock->owned_by_self()) {
271 assert(totalSizeInTree(root()) == totalSize(),
272 "_totalSize inconsistency");
273 }
274 )
275 return totalSize();
276 }
277
278 size_t minSize() const {
279 return min_tree_chunk_size;
280 }
281
282 double sum_of_squared_block_sizes() const {
283 return sum_of_squared_block_sizes(root());
284 }
285
286 Chunk* find_chunk_ends_at(HeapWord* target) const;
287
288 // Find the list with size "size" in the binary tree and update
289 // the statistics in the list according to "split" (chunk was
290 // split or coalesce) and "birth" (chunk was added or removed).
291 void dictCensusUpdate(size_t size, bool split, bool birth);
292 // Return true if the dictionary is overpopulated (more chunks of
293 // this size than desired) for size "size".
294 bool coalDictOverPopulated(size_t size);
295 // Methods called at the beginning of a sweep to prepare the
296 // statistics for the sweep.
297 void beginSweepDictCensus(double coalSurplusPercent,
298 float inter_sweep_current,
299 float inter_sweep_estimate,
300 float intra_sweep_estimate);
301 // Methods called after the end of a sweep to modify the
302 // statistics for the sweep.
303 void endSweepDictCensus(double splitSurplusPercent);
304 // Return the largest free chunk in the tree.
305 Chunk* findLargestDict() const;
306 // Accessors for statistics
307 void setTreeSurplus(double splitSurplusPercent);
308 void setTreeHints(void);
309 // Reset statistics for all the lists in the tree.
310 void clearTreeCensus(void);
311 // Print the statistcis for all the lists in the tree. Also may
312 // print out summaries.
313 void printDictCensus(void) const;
314 void print_free_lists(outputStream* st) const;
315
316 // For debugging. Returns the sum of the _returnedBytes for
317 // all lists in the tree.
318 size_t sumDictReturnedBytes() PRODUCT_RETURN0;
319 // Sets the _returnedBytes for all the lists in the tree to zero.
320 void initializeDictReturnedBytes() PRODUCT_RETURN;
321 // For debugging. Return the total number of chunks in the dictionary.
322 size_t totalCount() PRODUCT_RETURN0;
323
324 void reportStatistics() const;
325
326 void verify() const;
327 };
328
329 #endif // SHARE_VM_MEMORY_BINARYTREEDICTIONARY_HPP