hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/binaryTreeDictionary.hpp - platform/libcore - Git at Google

 /*
  * Copyright 2001-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */

 /*
  * A binary tree based search structure for free blocks.
  * This is currently used in the Concurrent Mark&Sweep implementation.
  */

 // A TreeList is a FreeList which can be used to maintain a
 // binary tree of free lists.

 class TreeChunk;
 class BinaryTreeDictionary;
 class AscendTreeCensusClosure;
 class DescendTreeCensusClosure;
 class DescendTreeSearchClosure;

 class TreeList: public FreeList {
   friend class TreeChunk;
   friend class BinaryTreeDictionary;
   friend class AscendTreeCensusClosure;
   friend class DescendTreeCensusClosure;
   friend class DescendTreeSearchClosure;
   TreeList* _parent;
   TreeList* _left;
   TreeList* _right;

  protected:
   TreeList* parent() const { return _parent; }
   TreeList* left()   const { return _left;   }
   TreeList* right()  const { return _right;  }

   // Accessors for links in tree.

   void setLeft(TreeList* tl) {
     _left   = tl;
     if (tl != NULL)
       tl->setParent(this);
   }
   void setRight(TreeList* tl) {
     _right  = tl;
     if (tl != NULL)
       tl->setParent(this);
   }
   void setParent(TreeList* 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* as_TreeList(TreeChunk* tc);
   static TreeList* as_TreeList(HeapWord* addr, size_t size);

   // Returns the head of the free list as a pointer to a TreeChunk.
   TreeChunk* head_as_TreeChunk();

   // Returns the first available chunk in the free list as a pointer
   // to a TreeChunk.
   TreeChunk* first_available();

   // 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* removeChunkReplaceIfNeeded(TreeChunk* tc);
   // See FreeList.
   void returnChunkAtHead(TreeChunk* tc);
   void returnChunkAtTail(TreeChunk* tc);
 };

 // A TreeChunk is a subclass of a FreeChunk 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.

 class TreeChunk : public FreeChunk {
   friend class TreeList;
   TreeList* _list;
   TreeList _embedded_list;  // if non-null, this chunk is on _list
  protected:
   TreeList* embedded_list() const { return (TreeList*) &_embedded_list; }
   void set_embedded_list(TreeList* v) { _embedded_list = *v; }
  public:
   TreeList* list() { return _list; }
   void set_list(TreeList* v) { _list = v; }
   static TreeChunk* as_TreeChunk(FreeChunk* 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(); }

   // debugging
   void verifyTreeChunkList() const;
 };

 const size_t MIN_TREE_CHUNK_SIZE  = sizeof(TreeChunk)/HeapWordSize;

 class BinaryTreeDictionary: public FreeBlockDictionary {
   bool       _splay;
   size_t     _totalSize;
   size_t     _totalFreeBlocks;
   TreeList* _root;

   // private accessors
   bool splay() const { return _splay; }
   void set_splay(bool v) { _splay = v; }
   size_t totalSize() const { return _totalSize; }
   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* root() const { return _root; }
   void set_root(TreeList* v) { _root = v; }

   // 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* getChunkFromTree(size_t size, 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* 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* removeChunkFromTree(TreeChunk* tc);
   // Remove the node in the trees starting at tl that has the
   // minimum value and return it.  Repair the tree as needed.
   TreeList* removeTreeMinimum(TreeList* tl);
   void       semiSplayStep(TreeList* tl);
   // Add this free chunk to the tree.
   void       insertChunkInTree(FreeChunk* freeChunk);
  public:
   void       verifyTree() const;
   // verify that the given chunk is in the tree.
   bool       verifyChunkInFreeLists(FreeChunk* tc) const;
  private:
   void          verifyTreeHelper(TreeList* tl) const;
   static size_t verifyPrevFreePtrs(TreeList* tl);

   // Returns the total number of chunks in the list.
   size_t     totalListLength(TreeList* tl) const;
   // Returns the total number of words in the chunks in the tree
   // starting at "tl".
   size_t     totalSizeInTree(TreeList* 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* const tl) const;
   // Returns the total number of free blocks in the tree starting
   // at "tl".
   size_t     totalFreeBlocksInTree(TreeList* tl) const;
   size_t     numFreeBlocks() const;
   size_t     treeHeight() const;
   size_t     treeHeightHelper(TreeList* tl) const;
   size_t     totalNodesInTree(TreeList* tl) const;
   size_t     totalNodesHelper(TreeList* tl) const;

  public:
   // Constructor
   BinaryTreeDictionary(MemRegion mr, bool splay = false);

   // 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.
   FreeChunk* getChunk(size_t size, Dither dither) {
     verify_par_locked();
     FreeChunk* res = getChunkFromTree(size, dither, splay());
     assert(res == NULL || res->isFree(),
            "Should be returning a free chunk");
     return res;
   }

   void returnChunk(FreeChunk* chunk) {
     verify_par_locked();
     insertChunkInTree(chunk);
   }

   void removeChunk(FreeChunk* chunk) {
     verify_par_locked();
     removeChunkFromTree((TreeChunk*)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());
   }

   FreeChunk* 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 sweep_current,
                                   float 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.
   FreeChunk* 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;

   // 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;
 };
	/*
	* Copyright 2001-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
	* CA 95054 USA or visit www.sun.com if you need additional information or
	* have any questions.
	*
	*/

	/*
	* A binary tree based search structure for free blocks.
	* This is currently used in the Concurrent Mark&Sweep implementation.
	*/

	// A TreeList is a FreeList which can be used to maintain a
	// binary tree of free lists.

	class TreeChunk;
	class BinaryTreeDictionary;
	class AscendTreeCensusClosure;
	class DescendTreeCensusClosure;
	class DescendTreeSearchClosure;

	class TreeList: public FreeList {
	friend class TreeChunk;
	friend class BinaryTreeDictionary;
	friend class AscendTreeCensusClosure;
	friend class DescendTreeCensusClosure;
	friend class DescendTreeSearchClosure;
	TreeList* _parent;
	TreeList* _left;
	TreeList* _right;

	protected:
	TreeList* parent() const { return _parent; }
	TreeList* left() const { return _left; }
	TreeList* right() const { return _right; }

	// Accessors for links in tree.

	void setLeft(TreeList* tl) {
	_left = tl;
	if (tl != NULL)
	tl->setParent(this);
	}
	void setRight(TreeList* tl) {
	_right = tl;
	if (tl != NULL)
	tl->setParent(this);
	}
	void setParent(TreeList* 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* as_TreeList(TreeChunk* tc);
	static TreeList* as_TreeList(HeapWord* addr, size_t size);

	// Returns the head of the free list as a pointer to a TreeChunk.
	TreeChunk* head_as_TreeChunk();

	// Returns the first available chunk in the free list as a pointer
	// to a TreeChunk.
	TreeChunk* first_available();

	// 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* removeChunkReplaceIfNeeded(TreeChunk* tc);
	// See FreeList.
	void returnChunkAtHead(TreeChunk* tc);
	void returnChunkAtTail(TreeChunk* tc);
	};

	// A TreeChunk is a subclass of a FreeChunk 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.

	class TreeChunk : public FreeChunk {
	friend class TreeList;
	TreeList* _list;
	TreeList _embedded_list; // if non-null, this chunk is on _list
	protected:
	TreeList* embedded_list() const { return (TreeList*) &_embedded_list; }
	void set_embedded_list(TreeList* v) { _embedded_list = *v; }
	public:
	TreeList* list() { return _list; }
	void set_list(TreeList* v) { _list = v; }
	static TreeChunk* as_TreeChunk(FreeChunk* 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(); }

	// debugging
	void verifyTreeChunkList() const;
	};

	const size_t MIN_TREE_CHUNK_SIZE = sizeof(TreeChunk)/HeapWordSize;

	class BinaryTreeDictionary: public FreeBlockDictionary {
	bool _splay;
	size_t _totalSize;
	size_t _totalFreeBlocks;
	TreeList* _root;

	// private accessors
	bool splay() const { return _splay; }
	void set_splay(bool v) { _splay = v; }
	size_t totalSize() const { return _totalSize; }
	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* root() const { return _root; }
	void set_root(TreeList* v) { _root = v; }

	// 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* getChunkFromTree(size_t size, 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* 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* removeChunkFromTree(TreeChunk* tc);
	// Remove the node in the trees starting at tl that has the
	// minimum value and return it. Repair the tree as needed.
	TreeList* removeTreeMinimum(TreeList* tl);
	void semiSplayStep(TreeList* tl);
	// Add this free chunk to the tree.
	void insertChunkInTree(FreeChunk* freeChunk);
	public:
	void verifyTree() const;
	// verify that the given chunk is in the tree.
	bool verifyChunkInFreeLists(FreeChunk* tc) const;
	private:
	void verifyTreeHelper(TreeList* tl) const;
	static size_t verifyPrevFreePtrs(TreeList* tl);

	// Returns the total number of chunks in the list.
	size_t totalListLength(TreeList* tl) const;
	// Returns the total number of words in the chunks in the tree
	// starting at "tl".
	size_t totalSizeInTree(TreeList* 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* const tl) const;
	// Returns the total number of free blocks in the tree starting
	// at "tl".
	size_t totalFreeBlocksInTree(TreeList* tl) const;
	size_t numFreeBlocks() const;
	size_t treeHeight() const;
	size_t treeHeightHelper(TreeList* tl) const;
	size_t totalNodesInTree(TreeList* tl) const;
	size_t totalNodesHelper(TreeList* tl) const;

	public:
	// Constructor
	BinaryTreeDictionary(MemRegion mr, bool splay = false);

	// 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.
	FreeChunk* getChunk(size_t size, Dither dither) {
	verify_par_locked();
	FreeChunk* res = getChunkFromTree(size, dither, splay());
	assert(res == NULL \|\| res->isFree(),
	"Should be returning a free chunk");
	return res;
	}

	void returnChunk(FreeChunk* chunk) {
	verify_par_locked();
	insertChunkInTree(chunk);
	}

	void removeChunk(FreeChunk* chunk) {
	verify_par_locked();
	removeChunkFromTree((TreeChunk*)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());
	}

	FreeChunk* 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 sweep_current,
	float 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.
	FreeChunk* 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;

	// 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;
	};