diff src/share/vm/gc_implementation/concurrentMarkSweep/freeList.cpp @ 0:a61af66fc99e

Initial load
author duke
date Sat, 01 Dec 2007 00:00:00 +0000
parents
children 6432c3bb6240
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/concurrentMarkSweep/freeList.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,304 @@
+/*
+ * 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.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_freeList.cpp.incl"
+
+// Free list.  A FreeList is used to access a linked list of chunks
+// of space in the heap.  The head and tail are maintained so that
+// items can be (as in the current implementation) added at the
+// at the tail of the list and removed from the head of the list to
+// maintain a FIFO queue.
+
+FreeList::FreeList() :
+  _head(NULL), _tail(NULL)
+#ifdef ASSERT
+  , _protecting_lock(NULL)
+#endif
+{
+  _size         = 0;
+  _count        = 0;
+  _hint         = 0;
+  init_statistics();
+}
+
+FreeList::FreeList(FreeChunk* fc) :
+  _head(fc), _tail(fc)
+#ifdef ASSERT
+  , _protecting_lock(NULL)
+#endif
+{
+  _size         = fc->size();
+  _count        = 1;
+  _hint         = 0;
+  init_statistics();
+#ifndef PRODUCT
+  _allocation_stats.set_returnedBytes(size() * HeapWordSize);
+#endif
+}
+
+FreeList::FreeList(HeapWord* addr, size_t size) :
+  _head((FreeChunk*) addr), _tail((FreeChunk*) addr)
+#ifdef ASSERT
+  , _protecting_lock(NULL)
+#endif
+{
+  assert(size > sizeof(FreeChunk), "size is too small");
+  head()->setSize(size);
+  _size         = size;
+  _count        = 1;
+  init_statistics();
+#ifndef PRODUCT
+  _allocation_stats.set_returnedBytes(_size * HeapWordSize);
+#endif
+}
+
+void FreeList::reset(size_t hint) {
+  set_count(0);
+  set_head(NULL);
+  set_tail(NULL);
+  set_hint(hint);
+}
+
+void FreeList::init_statistics() {
+  _allocation_stats.initialize();
+}
+
+FreeChunk* FreeList::getChunkAtHead() {
+  assert_proper_lock_protection();
+  assert(head() == NULL || head()->prev() == NULL, "list invariant");
+  assert(tail() == NULL || tail()->next() == NULL, "list invariant");
+  FreeChunk* fc = head();
+  if (fc != NULL) {
+    FreeChunk* nextFC = fc->next();
+    if (nextFC != NULL) {
+      // The chunk fc being removed has a "next".  Set the "next" to the
+      // "prev" of fc.
+      nextFC->linkPrev(NULL);
+    } else { // removed tail of list
+      link_tail(NULL);
+    }
+    link_head(nextFC);
+    decrement_count();
+  }
+  assert(head() == NULL || head()->prev() == NULL, "list invariant");
+  assert(tail() == NULL || tail()->next() == NULL, "list invariant");
+  return fc;
+}
+
+
+void FreeList::getFirstNChunksFromList(size_t n, FreeList* fl) {
+  assert_proper_lock_protection();
+  assert(fl->count() == 0, "Precondition");
+  if (count() > 0) {
+    int k = 1;
+    fl->set_head(head()); n--;
+    FreeChunk* tl = head();
+    while (tl->next() != NULL && n > 0) {
+      tl = tl->next(); n--; k++;
+    }
+    assert(tl != NULL, "Loop Inv.");
+
+    // First, fix up the list we took from.
+    FreeChunk* new_head = tl->next();
+    set_head(new_head);
+    set_count(count() - k);
+    if (new_head == NULL) {
+      set_tail(NULL);
+    } else {
+      new_head->linkPrev(NULL);
+    }
+    // Now we can fix up the tail.
+    tl->linkNext(NULL);
+    // And return the result.
+    fl->set_tail(tl);
+    fl->set_count(k);
+  }
+}
+
+// Remove this chunk from the list
+void FreeList::removeChunk(FreeChunk*fc) {
+   assert_proper_lock_protection();
+   assert(head() != NULL, "Remove from empty list");
+   assert(fc != NULL, "Remove a NULL chunk");
+   assert(size() == fc->size(), "Wrong list");
+   assert(head() == NULL || head()->prev() == NULL, "list invariant");
+   assert(tail() == NULL || tail()->next() == NULL, "list invariant");
+
+   FreeChunk* prevFC = fc->prev();
+   FreeChunk* nextFC = fc->next();
+   if (nextFC != NULL) {
+     // The chunk fc being removed has a "next".  Set the "next" to the
+     // "prev" of fc.
+     nextFC->linkPrev(prevFC);
+   } else { // removed tail of list
+     link_tail(prevFC);
+   }
+   if (prevFC == NULL) { // removed head of list
+     link_head(nextFC);
+     assert(nextFC == NULL || nextFC->prev() == NULL,
+       "Prev of head should be NULL");
+   } else {
+     prevFC->linkNext(nextFC);
+     assert(tail() != prevFC || prevFC->next() == NULL,
+       "Next of tail should be NULL");
+   }
+   decrement_count();
+#define TRAP_CODE 1
+#if TRAP_CODE
+   if (head() == NULL) {
+     guarantee(tail() == NULL, "INVARIANT");
+     guarantee(count() == 0, "INVARIANT");
+   }
+#endif
+   // clear next and prev fields of fc, debug only
+   NOT_PRODUCT(
+     fc->linkPrev(NULL);
+     fc->linkNext(NULL);
+   )
+   assert(fc->isFree(), "Should still be a free chunk");
+   assert(head() == NULL || head()->prev() == NULL, "list invariant");
+   assert(tail() == NULL || tail()->next() == NULL, "list invariant");
+   assert(head() == NULL || head()->size() == size(), "wrong item on list");
+   assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
+}
+
+// Add this chunk at the head of the list.
+void FreeList::returnChunkAtHead(FreeChunk* chunk, bool record_return) {
+  assert_proper_lock_protection();
+  assert(chunk != NULL, "insert a NULL chunk");
+  assert(size() == chunk->size(), "Wrong size");
+  assert(head() == NULL || head()->prev() == NULL, "list invariant");
+  assert(tail() == NULL || tail()->next() == NULL, "list invariant");
+
+  FreeChunk* oldHead = head();
+  assert(chunk != oldHead, "double insertion");
+  chunk->linkAfter(oldHead);
+  link_head(chunk);
+  if (oldHead == NULL) { // only chunk in list
+    assert(tail() == NULL, "inconsistent FreeList");
+    link_tail(chunk);
+  }
+  increment_count(); // of # of chunks in list
+  DEBUG_ONLY(
+    if (record_return) {
+      increment_returnedBytes_by(size()*HeapWordSize);
+    }
+  )
+  assert(head() == NULL || head()->prev() == NULL, "list invariant");
+  assert(tail() == NULL || tail()->next() == NULL, "list invariant");
+  assert(head() == NULL || head()->size() == size(), "wrong item on list");
+  assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
+}
+
+void FreeList::returnChunkAtHead(FreeChunk* chunk) {
+  assert_proper_lock_protection();
+  returnChunkAtHead(chunk, true);
+}
+
+// Add this chunk at the tail of the list.
+void FreeList::returnChunkAtTail(FreeChunk* chunk, bool record_return) {
+  assert_proper_lock_protection();
+  assert(head() == NULL || head()->prev() == NULL, "list invariant");
+  assert(tail() == NULL || tail()->next() == NULL, "list invariant");
+  assert(chunk != NULL, "insert a NULL chunk");
+  assert(size() == chunk->size(), "wrong size");
+
+  FreeChunk* oldTail = tail();
+  assert(chunk != oldTail, "double insertion");
+  if (oldTail != NULL) {
+    oldTail->linkAfter(chunk);
+  } else { // only chunk in list
+    assert(head() == NULL, "inconsistent FreeList");
+    link_head(chunk);
+  }
+  link_tail(chunk);
+  increment_count();  // of # of chunks in list
+  DEBUG_ONLY(
+    if (record_return) {
+      increment_returnedBytes_by(size()*HeapWordSize);
+    }
+  )
+  assert(head() == NULL || head()->prev() == NULL, "list invariant");
+  assert(tail() == NULL || tail()->next() == NULL, "list invariant");
+  assert(head() == NULL || head()->size() == size(), "wrong item on list");
+  assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
+}
+
+void FreeList::returnChunkAtTail(FreeChunk* chunk) {
+  returnChunkAtTail(chunk, true);
+}
+
+void FreeList::prepend(FreeList* fl) {
+  assert_proper_lock_protection();
+  if (fl->count() > 0) {
+    if (count() == 0) {
+      set_head(fl->head());
+      set_tail(fl->tail());
+      set_count(fl->count());
+    } else {
+      // Both are non-empty.
+      FreeChunk* fl_tail = fl->tail();
+      FreeChunk* this_head = head();
+      assert(fl_tail->next() == NULL, "Well-formedness of fl");
+      fl_tail->linkNext(this_head);
+      this_head->linkPrev(fl_tail);
+      set_head(fl->head());
+      set_count(count() + fl->count());
+    }
+    fl->set_head(NULL);
+    fl->set_tail(NULL);
+    fl->set_count(0);
+  }
+}
+
+// verifyChunkInFreeLists() is used to verify that an item is in this free list.
+// It is used as a debugging aid.
+bool FreeList::verifyChunkInFreeLists(FreeChunk* fc) const {
+  // This is an internal consistency check, not part of the check that the
+  // chunk is in the free lists.
+  guarantee(fc->size() == size(), "Wrong list is being searched");
+  FreeChunk* curFC = head();
+  while (curFC) {
+    // This is an internal consistency check.
+    guarantee(size() == curFC->size(), "Chunk is in wrong list.");
+    if (fc == curFC) {
+      return true;
+    }
+    curFC = curFC->next();
+  }
+  return false;
+}
+
+#ifndef PRODUCT
+void FreeList::assert_proper_lock_protection_work() const {
+#ifdef ASSERT
+  if (_protecting_lock != NULL &&
+      SharedHeap::heap()->n_par_threads() > 0) {
+    // Should become an assert.
+    guarantee(_protecting_lock->owned_by_self(), "FreeList RACE DETECTED");
+  }
+#endif
+}
+#endif