7131629: Generalize the CMS free list code

Make the FreeChunk, FreeList, TreeList, and BinaryTreeDictionary classes usable outside CMS.

Reviewed-by: brutisso, johnc, jwilhelm

hotspot/src/share/vm/memory/binaryTreeDictionary.hpp

@@ -0,0 +1,329 @@
+/*
+ * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_MEMORY_BINARYTREEDICTIONARY_HPP
+#define SHARE_VM_MEMORY_BINARYTREEDICTIONARY_HPP
+
+#include "memory/freeBlockDictionary.hpp"
+#include "memory/freeList.hpp"
+
+/*
+ * A binary tree based search structure for free blocks.
+ * This is currently used in the Concurrent Mark&Sweep implementation, but
+ * will be used for free block management for metadata.
+ */
+
+// A TreeList is a FreeList which can be used to maintain a
+// binary tree of free lists.
+
+template <class Chunk> class TreeChunk;
+template <class Chunk> class BinaryTreeDictionary;
+template <class Chunk> class AscendTreeCensusClosure;
+template <class Chunk> class DescendTreeCensusClosure;
+template <class Chunk> class DescendTreeSearchClosure;
+
+template <class Chunk>
+class TreeList: public FreeList<Chunk> {
+  friend class TreeChunk<Chunk>;
+  friend class BinaryTreeDictionary<Chunk>;
+  friend class AscendTreeCensusClosure<Chunk>;
+  friend class DescendTreeCensusClosure<Chunk>;
+  friend class DescendTreeSearchClosure<Chunk>;
+
+  TreeList<Chunk>* _parent;
+  TreeList<Chunk>* _left;
+  TreeList<Chunk>* _right;
+
+ protected:
+  TreeList<Chunk>* parent() const { return _parent; }
+  TreeList<Chunk>* left()   const { return _left;   }
+  TreeList<Chunk>* right()  const { return _right;  }
+
+  // Wrapper on call to base class, to get the template to compile.
+  Chunk* head() const { return FreeList<Chunk>::head(); }
+  Chunk* tail() const { return FreeList<Chunk>::tail(); }
+  void set_head(Chunk* head) { FreeList<Chunk>::set_head(head); }
+  void set_tail(Chunk* tail) { FreeList<Chunk>::set_tail(tail); }
+
+  size_t size() const { return FreeList<Chunk>::size(); }
+
+  // Accessors for links in tree.
+
+  void setLeft(TreeList<Chunk>* tl) {
+    _left   = tl;
+    if (tl != NULL)
+      tl->setParent(this);
+  }
+  void setRight(TreeList<Chunk>* tl) {
+    _right  = tl;
+    if (tl != NULL)
+      tl->setParent(this);
+  }
+  void setParent(TreeList<Chunk>* tl)  { _parent = tl;   }
+
+  void clearLeft()               { _left = NULL;   }
+  void clearRight()              { _right = NULL;  }
+  void clearParent()             { _parent = NULL; }
+  void initialize()              { clearLeft(); clearRight(), clearParent(); }
+
+  // For constructing a TreeList from a Tree chunk or
+  // address and size.
+  static TreeList<Chunk>* as_TreeList(TreeChunk<Chunk>* tc);
+  static TreeList<Chunk>* as_TreeList(HeapWord* addr, size_t size);
+
+  // Returns the head of the free list as a pointer to a TreeChunk.
+  TreeChunk<Chunk>* head_as_TreeChunk();
+
+  // Returns the first available chunk in the free list as a pointer
+  // to a TreeChunk.
+  TreeChunk<Chunk>* first_available();
+
+  // Returns the block with the largest heap address amongst
+  // those in the list for this size; potentially slow and expensive,
+  // use with caution!
+  TreeChunk<Chunk>* largest_address();
+
+  // removeChunkReplaceIfNeeded() removes the given "tc" from the TreeList.
+  // If "tc" is the first chunk in the list, it is also the
+  // TreeList that is the node in the tree.  removeChunkReplaceIfNeeded()
+  // returns the possibly replaced TreeList* for the node in
+  // the tree.  It also updates the parent of the original
+  // node to point to the new node.
+  TreeList<Chunk>* removeChunkReplaceIfNeeded(TreeChunk<Chunk>* tc);
+  // See FreeList.
+  void returnChunkAtHead(TreeChunk<Chunk>* tc);
+  void returnChunkAtTail(TreeChunk<Chunk>* tc);
+};
+
+// A TreeChunk is a subclass of a Chunk that additionally
+// maintains a pointer to the free list on which it is currently
+// linked.
+// A TreeChunk is also used as a node in the binary tree.  This
+// allows the binary tree to be maintained without any additional
+// storage (the free chunks are used).  In a binary tree the first
+// chunk in the free list is also the tree node.  Note that the
+// TreeChunk has an embedded TreeList for this purpose.  Because
+// the first chunk in the list is distinguished in this fashion
+// (also is the node in the tree), it is the last chunk to be found
+// on the free list for a node in the tree and is only removed if
+// it is the last chunk on the free list.
+
+template <class Chunk>
+class TreeChunk : public Chunk {
+  friend class TreeList<Chunk>;
+  TreeList<Chunk>* _list;
+  TreeList<Chunk> _embedded_list;  // if non-null, this chunk is on _list
+ protected:
+  TreeList<Chunk>* embedded_list() const { return (TreeList<Chunk>*) &_embedded_list; }
+  void set_embedded_list(TreeList<Chunk>* v) { _embedded_list = *v; }
+ public:
+  TreeList<Chunk>* list() { return _list; }
+  void set_list(TreeList<Chunk>* v) { _list = v; }
+  static TreeChunk<Chunk>* as_TreeChunk(Chunk* fc);
+  // Initialize fields in a TreeChunk that should be
+  // initialized when the TreeChunk is being added to
+  // a free list in the tree.
+  void initialize() { embedded_list()->initialize(); }
+
+  Chunk* next() const { return Chunk::next(); }
+  Chunk* prev() const { return Chunk::prev(); }
+  size_t size() const volatile { return Chunk::size(); }
+
+  // debugging
+  void verifyTreeChunkList() const;
+};
+
+
+template <class Chunk>
+class BinaryTreeDictionary: public FreeBlockDictionary<Chunk> {
+  friend class VMStructs;
+  bool       _splay;
+  size_t     _totalSize;
+  size_t     _totalFreeBlocks;
+  TreeList<Chunk>* _root;
+  bool       _adaptive_freelists;
+
+  // private accessors
+  bool splay() const { return _splay; }
+  void set_splay(bool v) { _splay = v; }
+  void set_totalSize(size_t v) { _totalSize = v; }
+  virtual void inc_totalSize(size_t v);
+  virtual void dec_totalSize(size_t v);
+  size_t totalFreeBlocks() const { return _totalFreeBlocks; }
+  void set_totalFreeBlocks(size_t v) { _totalFreeBlocks = v; }
+  TreeList<Chunk>* root() const { return _root; }
+  void set_root(TreeList<Chunk>* v) { _root = v; }
+  bool adaptive_freelists() { return _adaptive_freelists; }
+
+  // This field is added and can be set to point to the
+  // the Mutex used to synchronize access to the
+  // dictionary so that assertion checking can be done.
+  // For example it is set to point to _parDictionaryAllocLock.
+  NOT_PRODUCT(Mutex* _lock;)
+
+  // Remove a chunk of size "size" or larger from the tree and
+  // return it.  If the chunk
+  // is the last chunk of that size, remove the node for that size
+  // from the tree.
+  TreeChunk<Chunk>* getChunkFromTree(size_t size, enum FreeBlockDictionary<Chunk>::Dither dither, bool splay);
+  // Return a list of the specified size or NULL from the tree.
+  // The list is not removed from the tree.
+  TreeList<Chunk>* findList (size_t size) const;
+  // Remove this chunk from the tree.  If the removal results
+  // in an empty list in the tree, remove the empty list.
+  TreeChunk<Chunk>* removeChunkFromTree(TreeChunk<Chunk>* tc);
+  // Remove the node in the trees starting at tl that has the
+  // minimum value and return it.  Repair the tree as needed.
+  TreeList<Chunk>* removeTreeMinimum(TreeList<Chunk>* tl);
+  void       semiSplayStep(TreeList<Chunk>* tl);
+  // Add this free chunk to the tree.
+  void       insertChunkInTree(Chunk* freeChunk);
+ public:
+
+  static const size_t min_tree_chunk_size  = sizeof(TreeChunk<Chunk>)/HeapWordSize;
+
+  void       verifyTree() const;
+  // verify that the given chunk is in the tree.
+  bool       verifyChunkInFreeLists(Chunk* tc) const;
+ private:
+  void          verifyTreeHelper(TreeList<Chunk>* tl) const;
+  static size_t verifyPrevFreePtrs(TreeList<Chunk>* tl);
+
+  // Returns the total number of chunks in the list.
+  size_t     totalListLength(TreeList<Chunk>* tl) const;
+  // Returns the total number of words in the chunks in the tree
+  // starting at "tl".
+  size_t     totalSizeInTree(TreeList<Chunk>* tl) const;
+  // Returns the sum of the square of the size of each block
+  // in the tree starting at "tl".
+  double     sum_of_squared_block_sizes(TreeList<Chunk>* const tl) const;
+  // Returns the total number of free blocks in the tree starting
+  // at "tl".
+  size_t     totalFreeBlocksInTree(TreeList<Chunk>* tl) const;
+  size_t     numFreeBlocks() const;
+  size_t     treeHeight() const;
+  size_t     treeHeightHelper(TreeList<Chunk>* tl) const;
+  size_t     totalNodesInTree(TreeList<Chunk>* tl) const;
+  size_t     totalNodesHelper(TreeList<Chunk>* tl) const;
+
+ public:
+  // Constructor
+  BinaryTreeDictionary(bool adaptive_freelists, bool splay = false);
+  BinaryTreeDictionary(MemRegion mr, bool adaptive_freelists, bool splay = false);
+
+  // Public accessors
+  size_t totalSize() const { return _totalSize; }
+
+  // Reset the dictionary to the initial conditions with
+  // a single free chunk.
+  void       reset(MemRegion mr);
+  void       reset(HeapWord* addr, size_t size);
+  // Reset the dictionary to be empty.
+  void       reset();
+
+  // Return a chunk of size "size" or greater from
+  // the tree.
+  // want a better dynamic splay strategy for the future.
+  Chunk* getChunk(size_t size, enum FreeBlockDictionary<Chunk>::Dither dither) {
+    FreeBlockDictionary<Chunk>::verify_par_locked();
+    Chunk* res = getChunkFromTree(size, dither, splay());
+    assert(res == NULL || res->isFree(),
+           "Should be returning a free chunk");
+    return res;
+  }
+
+  void returnChunk(Chunk* chunk) {
+    FreeBlockDictionary<Chunk>::verify_par_locked();
+    insertChunkInTree(chunk);
+  }
+
+  void removeChunk(Chunk* chunk) {
+    FreeBlockDictionary<Chunk>::verify_par_locked();
+    removeChunkFromTree((TreeChunk<Chunk>*)chunk);
+    assert(chunk->isFree(), "Should still be a free chunk");
+  }
+
+  size_t     maxChunkSize() const;
+  size_t     totalChunkSize(debug_only(const Mutex* lock)) const {
+    debug_only(
+      if (lock != NULL && lock->owned_by_self()) {
+        assert(totalSizeInTree(root()) == totalSize(),
+               "_totalSize inconsistency");
+      }
+    )
+    return totalSize();
+  }
+
+  size_t     minSize() const {
+    return min_tree_chunk_size;
+  }
+
+  double     sum_of_squared_block_sizes() const {
+    return sum_of_squared_block_sizes(root());
+  }
+
+  Chunk* find_chunk_ends_at(HeapWord* target) const;
+
+  // Find the list with size "size" in the binary tree and update
+  // the statistics in the list according to "split" (chunk was
+  // split or coalesce) and "birth" (chunk was added or removed).
+  void       dictCensusUpdate(size_t size, bool split, bool birth);
+  // Return true if the dictionary is overpopulated (more chunks of
+  // this size than desired) for size "size".
+  bool       coalDictOverPopulated(size_t size);
+  // Methods called at the beginning of a sweep to prepare the
+  // statistics for the sweep.
+  void       beginSweepDictCensus(double coalSurplusPercent,
+                                  float inter_sweep_current,
+                                  float inter_sweep_estimate,
+                                  float intra_sweep_estimate);
+  // Methods called after the end of a sweep to modify the
+  // statistics for the sweep.
+  void       endSweepDictCensus(double splitSurplusPercent);
+  // Return the largest free chunk in the tree.
+  Chunk* findLargestDict() const;
+  // Accessors for statistics
+  void       setTreeSurplus(double splitSurplusPercent);
+  void       setTreeHints(void);
+  // Reset statistics for all the lists in the tree.
+  void       clearTreeCensus(void);
+  // Print the statistcis for all the lists in the tree.  Also may
+  // print out summaries.
+  void       printDictCensus(void) const;
+  void       print_free_lists(outputStream* st) const;
+
+  // For debugging.  Returns the sum of the _returnedBytes for
+  // all lists in the tree.
+  size_t     sumDictReturnedBytes()     PRODUCT_RETURN0;
+  // Sets the _returnedBytes for all the lists in the tree to zero.
+  void       initializeDictReturnedBytes()      PRODUCT_RETURN;
+  // For debugging.  Return the total number of chunks in the dictionary.
+  size_t     totalCount()       PRODUCT_RETURN0;
+
+  void       reportStatistics() const;
+
+  void       verify() const;
+};
+
+#endif // SHARE_VM_MEMORY_BINARYTREEDICTIONARY_HPP