jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/concurrentMarkSweep/binaryTreeDictionary.cpp@179464550c7d (annotated)

src/share/vm/gc_implementation/concurrentMarkSweep/binaryTreeDictionary.cpp@179464550c7d (annotated)

src/share/vm/gc_implementation/concurrentMarkSweep/binaryTreeDictionary.cpp

Fri, 10 Sep 2010 17:07:55 -0700

author: ysr
date: Fri, 10 Sep 2010 17:07:55 -0700
changeset 2132: 179464550c7d
parent 1907: c18cbe5936b8
child 2314: f95d63e2154a
permissions: -rw-r--r--

6983930: CMS: Various small cleanups ca September 2010
Summary: Fixed comment/documentation typos; converted some guarantee()s to assert()s.
Reviewed-by: jmasa

 /*
  * Copyright (c) 2001, 2008, 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 "incls/_precompiled.incl"
 # include "incls/_binaryTreeDictionary.cpp.incl"
 ////////////////////////////////////////////////////////////////////////////////
 // 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");
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/concurrentMarkSweep/binaryTreeDictionary.cpp@179464550c7d (annotated)

src/share/vm/gc_implementation/concurrentMarkSweep/binaryTreeDictionary.cpp