--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/binaryTreeDictionary.cpp Wed May 09 13:07:49 2012 -0700
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,1257 +0,0 @@
-/*
- * Copyright (c) 2001, 2010, 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.
- *
- */
-
-#include "precompiled.hpp"
-#include "gc_implementation/concurrentMarkSweep/binaryTreeDictionary.hpp"
-#include "gc_implementation/shared/allocationStats.hpp"
-#include "gc_implementation/shared/spaceDecorator.hpp"
-#include "memory/space.inline.hpp"
-#include "runtime/globals.hpp"
-#include "utilities/ostream.hpp"
-
-////////////////////////////////////////////////////////////////////////////////
-// A binary tree based search structure for free blocks.
-// This is currently used in the Concurrent Mark&Sweep implementation.
-////////////////////////////////////////////////////////////////////////////////
-
-TreeChunk* TreeChunk::as_TreeChunk(FreeChunk* fc) {
- // Do some assertion checking here.
- return (TreeChunk*) fc;
-}
-
-void TreeChunk::verifyTreeChunkList() const {
- TreeChunk* nextTC = (TreeChunk*)next();
- if (prev() != NULL) { // interior list node shouldn'r have tree fields
- guarantee(embedded_list()->parent() == NULL && embedded_list()->left() == NULL &&
- embedded_list()->right() == NULL, "should be clear");
- }
- if (nextTC != NULL) {
- guarantee(as_TreeChunk(nextTC->prev()) == this, "broken chain");
- guarantee(nextTC->size() == size(), "wrong size");
- nextTC->verifyTreeChunkList();
- }
-}
-
-
-TreeList* TreeList::as_TreeList(TreeChunk* tc) {
- // This first free chunk in the list will be the tree list.
- assert(tc->size() >= sizeof(TreeChunk), "Chunk is too small for a TreeChunk");
- TreeList* tl = tc->embedded_list();
- tc->set_list(tl);
-#ifdef ASSERT
- tl->set_protecting_lock(NULL);
-#endif
- tl->set_hint(0);
- tl->set_size(tc->size());
- tl->link_head(tc);
- tl->link_tail(tc);
- tl->set_count(1);
- tl->init_statistics(true /* split_birth */);
- tl->setParent(NULL);
- tl->setLeft(NULL);
- tl->setRight(NULL);
- return tl;
-}
-
-TreeList* TreeList::as_TreeList(HeapWord* addr, size_t size) {
- TreeChunk* tc = (TreeChunk*) addr;
- assert(size >= sizeof(TreeChunk), "Chunk is too small for a TreeChunk");
- // The space in the heap will have been mangled initially but
- // is not remangled when a free chunk is returned to the free list
- // (since it is used to maintain the chunk on the free list).
- assert((ZapUnusedHeapArea &&
- SpaceMangler::is_mangled((HeapWord*) tc->size_addr()) &&
- SpaceMangler::is_mangled((HeapWord*) tc->prev_addr()) &&
- SpaceMangler::is_mangled((HeapWord*) tc->next_addr())) ||
- (tc->size() == 0 && tc->prev() == NULL && tc->next() == NULL),
- "Space should be clear or mangled");
- tc->setSize(size);
- tc->linkPrev(NULL);
- tc->linkNext(NULL);
- TreeList* tl = TreeList::as_TreeList(tc);
- return tl;
-}
-
-TreeList* TreeList::removeChunkReplaceIfNeeded(TreeChunk* tc) {
-
- TreeList* retTL = this;
- FreeChunk* list = head();
- assert(!list || list != list->next(), "Chunk on list twice");
- assert(tc != NULL, "Chunk being removed is NULL");
- assert(parent() == NULL || this == parent()->left() ||
- this == parent()->right(), "list is inconsistent");
- assert(tc->isFree(), "Header is not marked correctly");
- assert(head() == NULL || head()->prev() == NULL, "list invariant");
- assert(tail() == NULL || tail()->next() == NULL, "list invariant");
-
- FreeChunk* prevFC = tc->prev();
- TreeChunk* nextTC = TreeChunk::as_TreeChunk(tc->next());
- assert(list != NULL, "should have at least the target chunk");
-
- // Is this the first item on the list?
- if (tc == list) {
- // The "getChunk..." functions for a TreeList will not return the
- // first chunk in the list unless it is the last chunk in the list
- // because the first chunk is also acting as the tree node.
- // When coalescing happens, however, the first chunk in the a tree
- // list can be the start of a free range. Free ranges are removed
- // from the free lists so that they are not available to be
- // allocated when the sweeper yields (giving up the free list lock)
- // to allow mutator activity. If this chunk is the first in the
- // list and is not the last in the list, do the work to copy the
- // TreeList from the first chunk to the next chunk and update all
- // the TreeList pointers in the chunks in the list.
- if (nextTC == NULL) {
- assert(prevFC == NULL, "Not last chunk in the list");
- set_tail(NULL);
- set_head(NULL);
- } else {
- // copy embedded list.
- nextTC->set_embedded_list(tc->embedded_list());
- retTL = nextTC->embedded_list();
- // Fix the pointer to the list in each chunk in the list.
- // This can be slow for a long list. Consider having
- // an option that does not allow the first chunk on the
- // list to be coalesced.
- for (TreeChunk* curTC = nextTC; curTC != NULL;
- curTC = TreeChunk::as_TreeChunk(curTC->next())) {
- curTC->set_list(retTL);
- }
- // Fix the parent to point to the new TreeList.
- if (retTL->parent() != NULL) {
- if (this == retTL->parent()->left()) {
- retTL->parent()->setLeft(retTL);
- } else {
- assert(this == retTL->parent()->right(), "Parent is incorrect");
- retTL->parent()->setRight(retTL);
- }
- }
- // Fix the children's parent pointers to point to the
- // new list.
- assert(right() == retTL->right(), "Should have been copied");
- if (retTL->right() != NULL) {
- retTL->right()->setParent(retTL);
- }
- assert(left() == retTL->left(), "Should have been copied");
- if (retTL->left() != NULL) {
- retTL->left()->setParent(retTL);
- }
- retTL->link_head(nextTC);
- assert(nextTC->isFree(), "Should be a free chunk");
- }
- } else {
- if (nextTC == NULL) {
- // Removing chunk at tail of list
- link_tail(prevFC);
- }
- // Chunk is interior to the list
- prevFC->linkAfter(nextTC);
- }
-
- // Below this point the embeded TreeList being used for the
- // tree node may have changed. Don't use "this"
- // TreeList*.
- // chunk should still be a free chunk (bit set in _prev)
- assert(!retTL->head() || retTL->size() == retTL->head()->size(),
- "Wrong sized chunk in list");
- debug_only(
- tc->linkPrev(NULL);
- tc->linkNext(NULL);
- tc->set_list(NULL);
- bool prev_found = false;
- bool next_found = false;
- for (FreeChunk* curFC = retTL->head();
- curFC != NULL; curFC = curFC->next()) {
- assert(curFC != tc, "Chunk is still in list");
- if (curFC == prevFC) {
- prev_found = true;
- }
- if (curFC == nextTC) {
- next_found = true;
- }
- }
- assert(prevFC == NULL || prev_found, "Chunk was lost from list");
- assert(nextTC == NULL || next_found, "Chunk was lost from list");
- assert(retTL->parent() == NULL ||
- retTL == retTL->parent()->left() ||
- retTL == retTL->parent()->right(),
- "list is inconsistent");
- )
- retTL->decrement_count();
-
- assert(tc->isFree(), "Should still be a free chunk");
- assert(retTL->head() == NULL || retTL->head()->prev() == NULL,
- "list invariant");
- assert(retTL->tail() == NULL || retTL->tail()->next() == NULL,
- "list invariant");
- return retTL;
-}
-void TreeList::returnChunkAtTail(TreeChunk* chunk) {
- assert(chunk != NULL, "returning NULL chunk");
- assert(chunk->list() == this, "list should be set for chunk");
- assert(tail() != NULL, "The tree list is embedded in the first chunk");
- // which means that the list can never be empty.
- assert(!verifyChunkInFreeLists(chunk), "Double entry");
- assert(head() == NULL || head()->prev() == NULL, "list invariant");
- assert(tail() == NULL || tail()->next() == NULL, "list invariant");
-
- FreeChunk* fc = tail();
- fc->linkAfter(chunk);
- link_tail(chunk);
-
- assert(!tail() || size() == tail()->size(), "Wrong sized chunk in list");
- increment_count();
- debug_only(increment_returnedBytes_by(chunk->size()*sizeof(HeapWord));)
- assert(head() == NULL || head()->prev() == NULL, "list invariant");
- assert(tail() == NULL || tail()->next() == NULL, "list invariant");
-}
-
-// Add this chunk at the head of the list. "At the head of the list"
-// is defined to be after the chunk pointer to by head(). This is
-// because the TreeList is embedded in the first TreeChunk in the
-// list. See the definition of TreeChunk.
-void TreeList::returnChunkAtHead(TreeChunk* chunk) {
- assert(chunk->list() == this, "list should be set for chunk");
- assert(head() != NULL, "The tree list is embedded in the first chunk");
- assert(chunk != NULL, "returning NULL chunk");
- assert(!verifyChunkInFreeLists(chunk), "Double entry");
- assert(head() == NULL || head()->prev() == NULL, "list invariant");
- assert(tail() == NULL || tail()->next() == NULL, "list invariant");
-
- FreeChunk* fc = head()->next();
- if (fc != NULL) {
- chunk->linkAfter(fc);
- } else {
- assert(tail() == NULL, "List is inconsistent");
- link_tail(chunk);
- }
- head()->linkAfter(chunk);
- assert(!head() || size() == head()->size(), "Wrong sized chunk in list");
- increment_count();
- debug_only(increment_returnedBytes_by(chunk->size()*sizeof(HeapWord));)
- assert(head() == NULL || head()->prev() == NULL, "list invariant");
- assert(tail() == NULL || tail()->next() == NULL, "list invariant");
-}
-
-TreeChunk* TreeList::head_as_TreeChunk() {
- assert(head() == NULL || TreeChunk::as_TreeChunk(head())->list() == this,
- "Wrong type of chunk?");
- return TreeChunk::as_TreeChunk(head());
-}
-
-TreeChunk* TreeList::first_available() {
- assert(head() != NULL, "The head of the list cannot be NULL");
- FreeChunk* fc = head()->next();
- TreeChunk* retTC;
- if (fc == NULL) {
- retTC = head_as_TreeChunk();
- } else {
- retTC = TreeChunk::as_TreeChunk(fc);
- }
- assert(retTC->list() == this, "Wrong type of chunk.");
- return retTC;
-}
-
-// Returns the block with the largest heap address amongst
-// those in the list for this size; potentially slow and expensive,
-// use with caution!
-TreeChunk* TreeList::largest_address() {
- assert(head() != NULL, "The head of the list cannot be NULL");
- FreeChunk* fc = head()->next();
- TreeChunk* retTC;
- if (fc == NULL) {
- retTC = head_as_TreeChunk();
- } else {
- // walk down the list and return the one with the highest
- // heap address among chunks of this size.
- FreeChunk* last = fc;
- while (fc->next() != NULL) {
- if ((HeapWord*)last < (HeapWord*)fc) {
- last = fc;
- }
- fc = fc->next();
- }
- retTC = TreeChunk::as_TreeChunk(last);
- }
- assert(retTC->list() == this, "Wrong type of chunk.");
- return retTC;
-}
-
-BinaryTreeDictionary::BinaryTreeDictionary(MemRegion mr, bool splay):
- _splay(splay)
-{
- assert(mr.byte_size() > MIN_TREE_CHUNK_SIZE, "minimum chunk size");
-
- reset(mr);
- assert(root()->left() == NULL, "reset check failed");
- assert(root()->right() == NULL, "reset check failed");
- assert(root()->head()->next() == NULL, "reset check failed");
- assert(root()->head()->prev() == NULL, "reset check failed");
- assert(totalSize() == root()->size(), "reset check failed");
- assert(totalFreeBlocks() == 1, "reset check failed");
-}
-
-void BinaryTreeDictionary::inc_totalSize(size_t inc) {
- _totalSize = _totalSize + inc;
-}
-
-void BinaryTreeDictionary::dec_totalSize(size_t dec) {
- _totalSize = _totalSize - dec;
-}
-
-void BinaryTreeDictionary::reset(MemRegion mr) {
- assert(mr.byte_size() > MIN_TREE_CHUNK_SIZE, "minimum chunk size");
- set_root(TreeList::as_TreeList(mr.start(), mr.word_size()));
- set_totalSize(mr.word_size());
- set_totalFreeBlocks(1);
-}
-
-void BinaryTreeDictionary::reset(HeapWord* addr, size_t byte_size) {
- MemRegion mr(addr, heap_word_size(byte_size));
- reset(mr);
-}
-
-void BinaryTreeDictionary::reset() {
- set_root(NULL);
- set_totalSize(0);
- set_totalFreeBlocks(0);
-}
-
-// Get a free block of size at least size from tree, or NULL.
-// If a splay step is requested, the removal algorithm (only) incorporates
-// a splay step as follows:
-// . the search proceeds down the tree looking for a possible
-// match. At the (closest) matching location, an appropriate splay step is applied
-// (zig, zig-zig or zig-zag). A chunk of the appropriate size is then returned
-// if available, and if it's the last chunk, the node is deleted. A deteleted
-// node is replaced in place by its tree successor.
-TreeChunk*
-BinaryTreeDictionary::getChunkFromTree(size_t size, Dither dither, bool splay)
-{
- TreeList *curTL, *prevTL;
- TreeChunk* retTC = NULL;
- assert(size >= MIN_TREE_CHUNK_SIZE, "minimum chunk size");
- if (FLSVerifyDictionary) {
- verifyTree();
- }
- // starting at the root, work downwards trying to find match.
- // Remember the last node of size too great or too small.
- for (prevTL = curTL = root(); curTL != NULL;) {
- if (curTL->size() == size) { // exact match
- break;
- }
- prevTL = curTL;
- if (curTL->size() < size) { // proceed to right sub-tree
- curTL = curTL->right();
- } else { // proceed to left sub-tree
- assert(curTL->size() > size, "size inconsistency");
- curTL = curTL->left();
- }
- }
- if (curTL == NULL) { // couldn't find exact match
- // try and find the next larger size by walking back up the search path
- for (curTL = prevTL; curTL != NULL;) {
- if (curTL->size() >= size) break;
- else curTL = curTL->parent();
- }
- assert(curTL == NULL || curTL->count() > 0,
- "An empty list should not be in the tree");
- }
- if (curTL != NULL) {
- assert(curTL->size() >= size, "size inconsistency");
- if (UseCMSAdaptiveFreeLists) {
-
- // A candidate chunk has been found. If it is already under
- // populated, get a chunk associated with the hint for this
- // chunk.
- if (curTL->surplus() <= 0) {
- /* Use the hint to find a size with a surplus, and reset the hint. */
- TreeList* hintTL = curTL;
- while (hintTL->hint() != 0) {
- assert(hintTL->hint() == 0 || hintTL->hint() > hintTL->size(),
- "hint points in the wrong direction");
- hintTL = findList(hintTL->hint());
- assert(curTL != hintTL, "Infinite loop");
- if (hintTL == NULL ||
- hintTL == curTL /* Should not happen but protect against it */ ) {
- // No useful hint. Set the hint to NULL and go on.
- curTL->set_hint(0);
- break;
- }
- assert(hintTL->size() > size, "hint is inconsistent");
- if (hintTL->surplus() > 0) {
- // The hint led to a list that has a surplus. Use it.
- // Set the hint for the candidate to an overpopulated
- // size.
- curTL->set_hint(hintTL->size());
- // Change the candidate.
- curTL = hintTL;
- break;
- }
- // The evm code reset the hint of the candidate as
- // at an interim point. Why? Seems like this leaves
- // the hint pointing to a list that didn't work.
- // curTL->set_hint(hintTL->size());
- }
- }
- }
- // don't waste time splaying if chunk's singleton
- if (splay && curTL->head()->next() != NULL) {
- semiSplayStep(curTL);
- }
- retTC = curTL->first_available();
- assert((retTC != NULL) && (curTL->count() > 0),
- "A list in the binary tree should not be NULL");
- assert(retTC->size() >= size,
- "A chunk of the wrong size was found");
- removeChunkFromTree(retTC);
- assert(retTC->isFree(), "Header is not marked correctly");
- }
-
- if (FLSVerifyDictionary) {
- verify();
- }
- return retTC;
-}
-
-TreeList* BinaryTreeDictionary::findList(size_t size) const {
- TreeList* curTL;
- for (curTL = root(); curTL != NULL;) {
- if (curTL->size() == size) { // exact match
- break;
- }
-
- if (curTL->size() < size) { // proceed to right sub-tree
- curTL = curTL->right();
- } else { // proceed to left sub-tree
- assert(curTL->size() > size, "size inconsistency");
- curTL = curTL->left();
- }
- }
- return curTL;
-}
-
-
-bool BinaryTreeDictionary::verifyChunkInFreeLists(FreeChunk* tc) const {
- size_t size = tc->size();
- TreeList* tl = findList(size);
- if (tl == NULL) {
- return false;
- } else {
- return tl->verifyChunkInFreeLists(tc);
- }
-}
-
-FreeChunk* BinaryTreeDictionary::findLargestDict() const {
- TreeList *curTL = root();
- if (curTL != NULL) {
- while(curTL->right() != NULL) curTL = curTL->right();
- return curTL->largest_address();
- } else {
- return NULL;
- }
-}
-
-// Remove the current chunk from the tree. If it is not the last
-// chunk in a list on a tree node, just unlink it.
-// If it is the last chunk in the list (the next link is NULL),
-// remove the node and repair the tree.
-TreeChunk*
-BinaryTreeDictionary::removeChunkFromTree(TreeChunk* tc) {
- assert(tc != NULL, "Should not call with a NULL chunk");
- assert(tc->isFree(), "Header is not marked correctly");
-
- TreeList *newTL, *parentTL;
- TreeChunk* retTC;
- TreeList* tl = tc->list();
- debug_only(
- bool removing_only_chunk = false;
- if (tl == _root) {
- if ((_root->left() == NULL) && (_root->right() == NULL)) {
- if (_root->count() == 1) {
- assert(_root->head() == tc, "Should only be this one chunk");
- removing_only_chunk = true;
- }
- }
- }
- )
- assert(tl != NULL, "List should be set");
- assert(tl->parent() == NULL || tl == tl->parent()->left() ||
- tl == tl->parent()->right(), "list is inconsistent");
-
- bool complicatedSplice = false;
-
- retTC = tc;
- // Removing this chunk can have the side effect of changing the node
- // (TreeList*) in the tree. If the node is the root, update it.
- TreeList* replacementTL = tl->removeChunkReplaceIfNeeded(tc);
- assert(tc->isFree(), "Chunk should still be free");
- assert(replacementTL->parent() == NULL ||
- replacementTL == replacementTL->parent()->left() ||
- replacementTL == replacementTL->parent()->right(),
- "list is inconsistent");
- if (tl == root()) {
- assert(replacementTL->parent() == NULL, "Incorrectly replacing root");
- set_root(replacementTL);
- }
- debug_only(
- if (tl != replacementTL) {
- assert(replacementTL->head() != NULL,
- "If the tree list was replaced, it should not be a NULL list");
- TreeList* rhl = replacementTL->head_as_TreeChunk()->list();
- TreeList* rtl = TreeChunk::as_TreeChunk(replacementTL->tail())->list();
- assert(rhl == replacementTL, "Broken head");
- assert(rtl == replacementTL, "Broken tail");
- assert(replacementTL->size() == tc->size(), "Broken size");
- }
- )
-
- // Does the tree need to be repaired?
- if (replacementTL->count() == 0) {
- assert(replacementTL->head() == NULL &&
- replacementTL->tail() == NULL, "list count is incorrect");
- // Find the replacement node for the (soon to be empty) node being removed.
- // if we have a single (or no) child, splice child in our stead
- if (replacementTL->left() == NULL) {
- // left is NULL so pick right. right may also be NULL.
- newTL = replacementTL->right();
- debug_only(replacementTL->clearRight();)
- } else if (replacementTL->right() == NULL) {
- // right is NULL
- newTL = replacementTL->left();
- debug_only(replacementTL->clearLeft();)
- } else { // we have both children, so, by patriarchal convention,
- // my replacement is least node in right sub-tree
- complicatedSplice = true;
- newTL = removeTreeMinimum(replacementTL->right());
- assert(newTL != NULL && newTL->left() == NULL &&
- newTL->right() == NULL, "sub-tree minimum exists");
- }
- // newTL is the replacement for the (soon to be empty) node.
- // newTL may be NULL.
- // should verify; we just cleanly excised our replacement
- if (FLSVerifyDictionary) {
- verifyTree();
- }
- // first make newTL my parent's child
- if ((parentTL = replacementTL->parent()) == NULL) {
- // newTL should be root
- assert(tl == root(), "Incorrectly replacing root");
- set_root(newTL);
- if (newTL != NULL) {
- newTL->clearParent();
- }
- } else if (parentTL->right() == replacementTL) {
- // replacementTL is a right child
- parentTL->setRight(newTL);
- } else { // replacementTL is a left child
- assert(parentTL->left() == replacementTL, "should be left child");
- parentTL->setLeft(newTL);
- }
- debug_only(replacementTL->clearParent();)
- if (complicatedSplice) { // we need newTL to get replacementTL's
- // two children
- assert(newTL != NULL &&
- newTL->left() == NULL && newTL->right() == NULL,
- "newTL should not have encumbrances from the past");
- // we'd like to assert as below:
- // assert(replacementTL->left() != NULL && replacementTL->right() != NULL,
- // "else !complicatedSplice");
- // ... however, the above assertion is too strong because we aren't
- // guaranteed that replacementTL->right() is still NULL.
- // Recall that we removed
- // the right sub-tree minimum from replacementTL.
- // That may well have been its right
- // child! So we'll just assert half of the above:
- assert(replacementTL->left() != NULL, "else !complicatedSplice");
- newTL->setLeft(replacementTL->left());
- newTL->setRight(replacementTL->right());
- debug_only(
- replacementTL->clearRight();
- replacementTL->clearLeft();
- )
- }
- assert(replacementTL->right() == NULL &&
- replacementTL->left() == NULL &&
- replacementTL->parent() == NULL,
- "delete without encumbrances");
- }
-
- assert(totalSize() >= retTC->size(), "Incorrect total size");
- dec_totalSize(retTC->size()); // size book-keeping
- assert(totalFreeBlocks() > 0, "Incorrect total count");
- set_totalFreeBlocks(totalFreeBlocks() - 1);
-
- assert(retTC != NULL, "null chunk?");
- assert(retTC->prev() == NULL && retTC->next() == NULL,
- "should return without encumbrances");
- if (FLSVerifyDictionary) {
- verifyTree();
- }
- assert(!removing_only_chunk || _root == NULL, "root should be NULL");
- return TreeChunk::as_TreeChunk(retTC);
-}
-
-// Remove the leftmost node (lm) in the tree and return it.
-// If lm has a right child, link it to the left node of
-// the parent of lm.
-TreeList* BinaryTreeDictionary::removeTreeMinimum(TreeList* tl) {
- assert(tl != NULL && tl->parent() != NULL, "really need a proper sub-tree");
- // locate the subtree minimum by walking down left branches
- TreeList* curTL = tl;
- for (; curTL->left() != NULL; curTL = curTL->left());
- // obviously curTL now has at most one child, a right child
- if (curTL != root()) { // Should this test just be removed?
- TreeList* parentTL = curTL->parent();
- if (parentTL->left() == curTL) { // curTL is a left child
- parentTL->setLeft(curTL->right());
- } else {
- // If the list tl has no left child, then curTL may be
- // the right child of parentTL.
- assert(parentTL->right() == curTL, "should be a right child");
- parentTL->setRight(curTL->right());
- }
- } else {
- // The only use of this method would not pass the root of the
- // tree (as indicated by the assertion above that the tree list
- // has a parent) but the specification does not explicitly exclude the
- // passing of the root so accomodate it.
- set_root(NULL);
- }
- debug_only(
- curTL->clearParent(); // Test if this needs to be cleared
- curTL->clearRight(); // recall, above, left child is already null
- )
- // we just excised a (non-root) node, we should still verify all tree invariants
- if (FLSVerifyDictionary) {
- verifyTree();
- }
- return curTL;
-}
-
-// Based on a simplification of the algorithm by Sleator and Tarjan (JACM 1985).
-// The simplifications are the following:
-// . we splay only when we delete (not when we insert)
-// . we apply a single spay step per deletion/access
-// By doing such partial splaying, we reduce the amount of restructuring,
-// while getting a reasonably efficient search tree (we think).
-// [Measurements will be needed to (in)validate this expectation.]
-
-void BinaryTreeDictionary::semiSplayStep(TreeList* tc) {
- // apply a semi-splay step at the given node:
- // . if root, norting needs to be done
- // . if child of root, splay once
- // . else zig-zig or sig-zag depending on path from grandparent
- if (root() == tc) return;
- warning("*** Splaying not yet implemented; "
- "tree operations may be inefficient ***");
-}
-
-void BinaryTreeDictionary::insertChunkInTree(FreeChunk* fc) {
- TreeList *curTL, *prevTL;
- size_t size = fc->size();
-
- assert(size >= MIN_TREE_CHUNK_SIZE, "too small to be a TreeList");
- if (FLSVerifyDictionary) {
- verifyTree();
- }
- // XXX: do i need to clear the FreeChunk fields, let me do it just in case
- // Revisit this later
-
- fc->clearNext();
- fc->linkPrev(NULL);
-
- // work down from the _root, looking for insertion point
- for (prevTL = curTL = root(); curTL != NULL;) {
- if (curTL->size() == size) // exact match
- break;
- prevTL = curTL;
- if (curTL->size() > size) { // follow left branch
- curTL = curTL->left();
- } else { // follow right branch
- assert(curTL->size() < size, "size inconsistency");
- curTL = curTL->right();
- }
- }
- TreeChunk* tc = TreeChunk::as_TreeChunk(fc);
- // This chunk is being returned to the binary tree. Its embedded
- // TreeList should be unused at this point.
- tc->initialize();
- if (curTL != NULL) { // exact match
- tc->set_list(curTL);
- curTL->returnChunkAtTail(tc);
- } else { // need a new node in tree
- tc->clearNext();
- tc->linkPrev(NULL);
- TreeList* newTL = TreeList::as_TreeList(tc);
- assert(((TreeChunk*)tc)->list() == newTL,
- "List was not initialized correctly");
- if (prevTL == NULL) { // we are the only tree node
- assert(root() == NULL, "control point invariant");
- set_root(newTL);
- } else { // insert under prevTL ...
- if (prevTL->size() < size) { // am right child
- assert(prevTL->right() == NULL, "control point invariant");
- prevTL->setRight(newTL);
- } else { // am left child
- assert(prevTL->size() > size && prevTL->left() == NULL, "cpt pt inv");
- prevTL->setLeft(newTL);
- }
- }
- }
- assert(tc->list() != NULL, "Tree list should be set");
-
- inc_totalSize(size);
- // Method 'totalSizeInTree' walks through the every block in the
- // tree, so it can cause significant performance loss if there are
- // many blocks in the tree
- assert(!FLSVerifyDictionary || totalSizeInTree(root()) == totalSize(), "_totalSize inconsistency");
- set_totalFreeBlocks(totalFreeBlocks() + 1);
- if (FLSVerifyDictionary) {
- verifyTree();
- }
-}
-
-size_t BinaryTreeDictionary::maxChunkSize() const {
- verify_par_locked();
- TreeList* tc = root();
- if (tc == NULL) return 0;
- for (; tc->right() != NULL; tc = tc->right());
- return tc->size();
-}
-
-size_t BinaryTreeDictionary::totalListLength(TreeList* tl) const {
- size_t res;
- res = tl->count();
-#ifdef ASSERT
- size_t cnt;
- FreeChunk* tc = tl->head();
- for (cnt = 0; tc != NULL; tc = tc->next(), cnt++);
- assert(res == cnt, "The count is not being maintained correctly");
-#endif
- return res;
-}
-
-size_t BinaryTreeDictionary::totalSizeInTree(TreeList* tl) const {
- if (tl == NULL)
- return 0;
- return (tl->size() * totalListLength(tl)) +
- totalSizeInTree(tl->left()) +
- totalSizeInTree(tl->right());
-}
-
-double BinaryTreeDictionary::sum_of_squared_block_sizes(TreeList* const tl) const {
- if (tl == NULL) {
- return 0.0;
- }
- double size = (double)(tl->size());
- double curr = size * size * totalListLength(tl);
- curr += sum_of_squared_block_sizes(tl->left());
- curr += sum_of_squared_block_sizes(tl->right());
- return curr;
-}
-
-size_t BinaryTreeDictionary::totalFreeBlocksInTree(TreeList* tl) const {
- if (tl == NULL)
- return 0;
- return totalListLength(tl) +
- totalFreeBlocksInTree(tl->left()) +
- totalFreeBlocksInTree(tl->right());
-}
-
-size_t BinaryTreeDictionary::numFreeBlocks() const {
- assert(totalFreeBlocksInTree(root()) == totalFreeBlocks(),
- "_totalFreeBlocks inconsistency");
- return totalFreeBlocks();
-}
-
-size_t BinaryTreeDictionary::treeHeightHelper(TreeList* tl) const {
- if (tl == NULL)
- return 0;
- return 1 + MAX2(treeHeightHelper(tl->left()),
- treeHeightHelper(tl->right()));
-}
-
-size_t BinaryTreeDictionary::treeHeight() const {
- return treeHeightHelper(root());
-}
-
-size_t BinaryTreeDictionary::totalNodesHelper(TreeList* tl) const {
- if (tl == NULL) {
- return 0;
- }
- return 1 + totalNodesHelper(tl->left()) +
- totalNodesHelper(tl->right());
-}
-
-size_t BinaryTreeDictionary::totalNodesInTree(TreeList* tl) const {
- return totalNodesHelper(root());
-}
-
-void BinaryTreeDictionary::dictCensusUpdate(size_t size, bool split, bool birth){
- TreeList* nd = findList(size);
- if (nd) {
- if (split) {
- if (birth) {
- nd->increment_splitBirths();
- nd->increment_surplus();
- } else {
- nd->increment_splitDeaths();
- nd->decrement_surplus();
- }
- } else {
- if (birth) {
- nd->increment_coalBirths();
- nd->increment_surplus();
- } else {
- nd->increment_coalDeaths();
- nd->decrement_surplus();
- }
- }
- }
- // A list for this size may not be found (nd == 0) if
- // This is a death where the appropriate list is now
- // empty and has been removed from the list.
- // This is a birth associated with a LinAB. The chunk
- // for the LinAB is not in the dictionary.
-}
-
-bool BinaryTreeDictionary::coalDictOverPopulated(size_t size) {
- if (FLSAlwaysCoalesceLarge) return true;
-
- TreeList* list_of_size = findList(size);
- // None of requested size implies overpopulated.
- return list_of_size == NULL || list_of_size->coalDesired() <= 0 ||
- list_of_size->count() > list_of_size->coalDesired();
-}
-
-// Closures for walking the binary tree.
-// do_list() walks the free list in a node applying the closure
-// to each free chunk in the list
-// do_tree() walks the nodes in the binary tree applying do_list()
-// to each list at each node.
-
-class TreeCensusClosure : public StackObj {
- protected:
- virtual void do_list(FreeList* fl) = 0;
- public:
- virtual void do_tree(TreeList* tl) = 0;
-};
-
-class AscendTreeCensusClosure : public TreeCensusClosure {
- public:
- void do_tree(TreeList* tl) {
- if (tl != NULL) {
- do_tree(tl->left());
- do_list(tl);
- do_tree(tl->right());
- }
- }
-};
-
-class DescendTreeCensusClosure : public TreeCensusClosure {
- public:
- void do_tree(TreeList* tl) {
- if (tl != NULL) {
- do_tree(tl->right());
- do_list(tl);
- do_tree(tl->left());
- }
- }
-};
-
-// For each list in the tree, calculate the desired, desired
-// coalesce, count before sweep, and surplus before sweep.
-class BeginSweepClosure : public AscendTreeCensusClosure {
- double _percentage;
- float _inter_sweep_current;
- float _inter_sweep_estimate;
- float _intra_sweep_estimate;
-
- public:
- BeginSweepClosure(double p, float inter_sweep_current,
- float inter_sweep_estimate,
- float intra_sweep_estimate) :
- _percentage(p),
- _inter_sweep_current(inter_sweep_current),
- _inter_sweep_estimate(inter_sweep_estimate),
- _intra_sweep_estimate(intra_sweep_estimate) { }
-
- void do_list(FreeList* fl) {
- double coalSurplusPercent = _percentage;
- fl->compute_desired(_inter_sweep_current, _inter_sweep_estimate, _intra_sweep_estimate);
- fl->set_coalDesired((ssize_t)((double)fl->desired() * coalSurplusPercent));
- fl->set_beforeSweep(fl->count());
- fl->set_bfrSurp(fl->surplus());
- }
-};
-
-// Used to search the tree until a condition is met.
-// Similar to TreeCensusClosure but searches the
-// tree and returns promptly when found.
-
-class TreeSearchClosure : public StackObj {
- protected:
- virtual bool do_list(FreeList* fl) = 0;
- public:
- virtual bool do_tree(TreeList* tl) = 0;
-};
-
-#if 0 // Don't need this yet but here for symmetry.
-class AscendTreeSearchClosure : public TreeSearchClosure {
- public:
- bool do_tree(TreeList* tl) {
- if (tl != NULL) {
- if (do_tree(tl->left())) return true;
- if (do_list(tl)) return true;
- if (do_tree(tl->right())) return true;
- }
- return false;
- }
-};
-#endif
-
-class DescendTreeSearchClosure : public TreeSearchClosure {
- public:
- bool do_tree(TreeList* tl) {
- if (tl != NULL) {
- if (do_tree(tl->right())) return true;
- if (do_list(tl)) return true;
- if (do_tree(tl->left())) return true;
- }
- return false;
- }
-};
-
-// Searches the tree for a chunk that ends at the
-// specified address.
-class EndTreeSearchClosure : public DescendTreeSearchClosure {
- HeapWord* _target;
- FreeChunk* _found;
-
- public:
- EndTreeSearchClosure(HeapWord* target) : _target(target), _found(NULL) {}
- bool do_list(FreeList* fl) {
- FreeChunk* item = fl->head();
- while (item != NULL) {
- if (item->end() == _target) {
- _found = item;
- return true;
- }
- item = item->next();
- }
- return false;
- }
- FreeChunk* found() { return _found; }
-};
-
-FreeChunk* BinaryTreeDictionary::find_chunk_ends_at(HeapWord* target) const {
- EndTreeSearchClosure etsc(target);
- bool found_target = etsc.do_tree(root());
- assert(found_target || etsc.found() == NULL, "Consistency check");
- assert(!found_target || etsc.found() != NULL, "Consistency check");
- return etsc.found();
-}
-
-void BinaryTreeDictionary::beginSweepDictCensus(double coalSurplusPercent,
- float inter_sweep_current, float inter_sweep_estimate, float intra_sweep_estimate) {
- BeginSweepClosure bsc(coalSurplusPercent, inter_sweep_current,
- inter_sweep_estimate,
- intra_sweep_estimate);
- bsc.do_tree(root());
-}
-
-// Closures and methods for calculating total bytes returned to the
-// free lists in the tree.
-NOT_PRODUCT(
- class InitializeDictReturnedBytesClosure : public AscendTreeCensusClosure {
- public:
- void do_list(FreeList* fl) {
- fl->set_returnedBytes(0);
- }
- };
-
- void BinaryTreeDictionary::initializeDictReturnedBytes() {
- InitializeDictReturnedBytesClosure idrb;
- idrb.do_tree(root());
- }
-
- class ReturnedBytesClosure : public AscendTreeCensusClosure {
- size_t _dictReturnedBytes;
- public:
- ReturnedBytesClosure() { _dictReturnedBytes = 0; }
- void do_list(FreeList* fl) {
- _dictReturnedBytes += fl->returnedBytes();
- }
- size_t dictReturnedBytes() { return _dictReturnedBytes; }
- };
-
- size_t BinaryTreeDictionary::sumDictReturnedBytes() {
- ReturnedBytesClosure rbc;
- rbc.do_tree(root());
-
- return rbc.dictReturnedBytes();
- }
-
- // Count the number of entries in the tree.
- class treeCountClosure : public DescendTreeCensusClosure {
- public:
- uint count;
- treeCountClosure(uint c) { count = c; }
- void do_list(FreeList* fl) {
- count++;
- }
- };
-
- size_t BinaryTreeDictionary::totalCount() {
- treeCountClosure ctc(0);
- ctc.do_tree(root());
- return ctc.count;
- }
-)
-
-// Calculate surpluses for the lists in the tree.
-class setTreeSurplusClosure : public AscendTreeCensusClosure {
- double percentage;
- public:
- setTreeSurplusClosure(double v) { percentage = v; }
- void do_list(FreeList* fl) {
- double splitSurplusPercent = percentage;
- fl->set_surplus(fl->count() -
- (ssize_t)((double)fl->desired() * splitSurplusPercent));
- }
-};
-
-void BinaryTreeDictionary::setTreeSurplus(double splitSurplusPercent) {
- setTreeSurplusClosure sts(splitSurplusPercent);
- sts.do_tree(root());
-}
-
-// Set hints for the lists in the tree.
-class setTreeHintsClosure : public DescendTreeCensusClosure {
- size_t hint;
- public:
- setTreeHintsClosure(size_t v) { hint = v; }
- void do_list(FreeList* fl) {
- fl->set_hint(hint);
- assert(fl->hint() == 0 || fl->hint() > fl->size(),
- "Current hint is inconsistent");
- if (fl->surplus() > 0) {
- hint = fl->size();
- }
- }
-};
-
-void BinaryTreeDictionary::setTreeHints(void) {
- setTreeHintsClosure sth(0);
- sth.do_tree(root());
-}
-
-// Save count before previous sweep and splits and coalesces.
-class clearTreeCensusClosure : public AscendTreeCensusClosure {
- void do_list(FreeList* fl) {
- fl->set_prevSweep(fl->count());
- fl->set_coalBirths(0);
- fl->set_coalDeaths(0);
- fl->set_splitBirths(0);
- fl->set_splitDeaths(0);
- }
-};
-
-void BinaryTreeDictionary::clearTreeCensus(void) {
- clearTreeCensusClosure ctc;
- ctc.do_tree(root());
-}
-
-// Do reporting and post sweep clean up.
-void BinaryTreeDictionary::endSweepDictCensus(double splitSurplusPercent) {
- // Does walking the tree 3 times hurt?
- setTreeSurplus(splitSurplusPercent);
- setTreeHints();
- if (PrintGC && Verbose) {
- reportStatistics();
- }
- clearTreeCensus();
-}
-
-// Print summary statistics
-void BinaryTreeDictionary::reportStatistics() const {
- verify_par_locked();
- gclog_or_tty->print("Statistics for BinaryTreeDictionary:\n"
- "------------------------------------\n");
- size_t totalSize = totalChunkSize(debug_only(NULL));
- size_t freeBlocks = numFreeBlocks();
- gclog_or_tty->print("Total Free Space: %d\n", totalSize);
- gclog_or_tty->print("Max Chunk Size: %d\n", maxChunkSize());
- gclog_or_tty->print("Number of Blocks: %d\n", freeBlocks);
- if (freeBlocks > 0) {
- gclog_or_tty->print("Av. Block Size: %d\n", totalSize/freeBlocks);
- }
- gclog_or_tty->print("Tree Height: %d\n", treeHeight());
-}
-
-// Print census information - counts, births, deaths, etc.
-// for each list in the tree. Also print some summary
-// information.
-class PrintTreeCensusClosure : public AscendTreeCensusClosure {
- int _print_line;
- size_t _totalFree;
- FreeList _total;
-
- public:
- PrintTreeCensusClosure() {
- _print_line = 0;
- _totalFree = 0;
- }
- FreeList* total() { return &_total; }
- size_t totalFree() { return _totalFree; }
- void do_list(FreeList* fl) {
- if (++_print_line >= 40) {
- FreeList::print_labels_on(gclog_or_tty, "size");
- _print_line = 0;
- }
- fl->print_on(gclog_or_tty);
- _totalFree += fl->count() * fl->size() ;
- total()->set_count( total()->count() + fl->count() );
- total()->set_bfrSurp( total()->bfrSurp() + fl->bfrSurp() );
- total()->set_surplus( total()->splitDeaths() + fl->surplus() );
- total()->set_desired( total()->desired() + fl->desired() );
- total()->set_prevSweep( total()->prevSweep() + fl->prevSweep() );
- total()->set_beforeSweep(total()->beforeSweep() + fl->beforeSweep());
- total()->set_coalBirths( total()->coalBirths() + fl->coalBirths() );
- total()->set_coalDeaths( total()->coalDeaths() + fl->coalDeaths() );
- total()->set_splitBirths(total()->splitBirths() + fl->splitBirths());
- total()->set_splitDeaths(total()->splitDeaths() + fl->splitDeaths());
- }
-};
-
-void BinaryTreeDictionary::printDictCensus(void) const {
-
- gclog_or_tty->print("\nBinaryTree\n");
- FreeList::print_labels_on(gclog_or_tty, "size");
- PrintTreeCensusClosure ptc;
- ptc.do_tree(root());
-
- FreeList* total = ptc.total();
- FreeList::print_labels_on(gclog_or_tty, " ");
- total->print_on(gclog_or_tty, "TOTAL\t");
- gclog_or_tty->print(
- "totalFree(words): " SIZE_FORMAT_W(16)
- " growth: %8.5f deficit: %8.5f\n",
- ptc.totalFree(),
- (double)(total->splitBirths() + total->coalBirths()
- - total->splitDeaths() - total->coalDeaths())
- /(total->prevSweep() != 0 ? (double)total->prevSweep() : 1.0),
- (double)(total->desired() - total->count())
- /(total->desired() != 0 ? (double)total->desired() : 1.0));
-}
-
-class PrintFreeListsClosure : public AscendTreeCensusClosure {
- outputStream* _st;
- int _print_line;
-
- public:
- PrintFreeListsClosure(outputStream* st) {
- _st = st;
- _print_line = 0;
- }
- void do_list(FreeList* fl) {
- if (++_print_line >= 40) {
- FreeList::print_labels_on(_st, "size");
- _print_line = 0;
- }
- fl->print_on(gclog_or_tty);
- size_t sz = fl->size();
- for (FreeChunk* fc = fl->head(); fc != NULL;
- fc = fc->next()) {
- _st->print_cr("\t[" PTR_FORMAT "," PTR_FORMAT ") %s",
- fc, (HeapWord*)fc + sz,
- fc->cantCoalesce() ? "\t CC" : "");
- }
- }
-};
-
-void BinaryTreeDictionary::print_free_lists(outputStream* st) const {
-
- FreeList::print_labels_on(st, "size");
- PrintFreeListsClosure pflc(st);
- pflc.do_tree(root());
-}
-
-// Verify the following tree invariants:
-// . _root has no parent
-// . parent and child point to each other
-// . each node's key correctly related to that of its child(ren)
-void BinaryTreeDictionary::verifyTree() const {
- guarantee(root() == NULL || totalFreeBlocks() == 0 ||
- totalSize() != 0, "_totalSize should't be 0?");
- guarantee(root() == NULL || root()->parent() == NULL, "_root shouldn't have parent");
- verifyTreeHelper(root());
-}
-
-size_t BinaryTreeDictionary::verifyPrevFreePtrs(TreeList* tl) {
- size_t ct = 0;
- for (FreeChunk* curFC = tl->head(); curFC != NULL; curFC = curFC->next()) {
- ct++;
- assert(curFC->prev() == NULL || curFC->prev()->isFree(),
- "Chunk should be free");
- }
- return ct;
-}
-
-// Note: this helper is recursive rather than iterative, so use with
-// caution on very deep trees; and watch out for stack overflow errors;
-// In general, to be used only for debugging.
-void BinaryTreeDictionary::verifyTreeHelper(TreeList* tl) const {
- if (tl == NULL)
- return;
- guarantee(tl->size() != 0, "A list must has a size");
- guarantee(tl->left() == NULL || tl->left()->parent() == tl,
- "parent<-/->left");
- guarantee(tl->right() == NULL || tl->right()->parent() == tl,
- "parent<-/->right");;
- guarantee(tl->left() == NULL || tl->left()->size() < tl->size(),
- "parent !> left");
- guarantee(tl->right() == NULL || tl->right()->size() > tl->size(),
- "parent !< left");
- guarantee(tl->head() == NULL || tl->head()->isFree(), "!Free");
- guarantee(tl->head() == NULL || tl->head_as_TreeChunk()->list() == tl,
- "list inconsistency");
- guarantee(tl->count() > 0 || (tl->head() == NULL && tl->tail() == NULL),
- "list count is inconsistent");
- guarantee(tl->count() > 1 || tl->head() == tl->tail(),
- "list is incorrectly constructed");
- size_t count = verifyPrevFreePtrs(tl);
- guarantee(count == (size_t)tl->count(), "Node count is incorrect");
- if (tl->head() != NULL) {
- tl->head_as_TreeChunk()->verifyTreeChunkList();
- }
- verifyTreeHelper(tl->left());
- verifyTreeHelper(tl->right());
-}
-
-void BinaryTreeDictionary::verify() const {
- verifyTree();
- guarantee(totalSize() == totalSizeInTree(root()), "Total Size inconsistency");
-}