7131629: Generalize the CMS free list code

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

Reviewed-by: brutisso, johnc, jwilhelm

hotspot/src/share/vm/memory/freeList.cpp

@@ -0,0 +1,370 @@
+/*
+ * 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 "memory/freeBlockDictionary.hpp"
+#include "memory/freeList.hpp"
+#include "memory/sharedHeap.hpp"
+#include "runtime/globals.hpp"
+#include "runtime/mutex.hpp"
+#include "runtime/vmThread.hpp"
+
+#ifndef SERIALGC
+#include "gc_implementation/concurrentMarkSweep/freeChunk.hpp"
+#endif // SERIALGC
+
+// 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.
+
+template <class Chunk>
+FreeList<Chunk>::FreeList() :
+  _head(NULL), _tail(NULL)
+#ifdef ASSERT
+  , _protecting_lock(NULL)
+#endif
+{
+  _size         = 0;
+  _count        = 0;
+  _hint         = 0;
+  init_statistics();
+}
+
+template <class Chunk>
+FreeList<Chunk>::FreeList(Chunk* 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
+}
+
+template <class Chunk>
+void FreeList<Chunk>::reset(size_t hint) {
+  set_count(0);
+  set_head(NULL);
+  set_tail(NULL);
+  set_hint(hint);
+}
+
+template <class Chunk>
+void FreeList<Chunk>::init_statistics(bool split_birth) {
+  _allocation_stats.initialize(split_birth);
+}
+
+template <class Chunk>
+Chunk* FreeList<Chunk>::getChunkAtHead() {
+  assert_proper_lock_protection();
+  assert(head() == NULL || head()->prev() == NULL, "list invariant");
+  assert(tail() == NULL || tail()->next() == NULL, "list invariant");
+  Chunk* fc = head();
+  if (fc != NULL) {
+    Chunk* 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;
+}
+
+
+template <class Chunk>
+void FreeList<Chunk>::getFirstNChunksFromList(size_t n, FreeList<Chunk>* fl) {
+  assert_proper_lock_protection();
+  assert(fl->count() == 0, "Precondition");
+  if (count() > 0) {
+    int k = 1;
+    fl->set_head(head()); n--;
+    Chunk* 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.
+    Chunk* 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
+template <class Chunk>
+void FreeList<Chunk>::removeChunk(Chunk*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");
+
+   Chunk* prevFC = fc->prev();
+   Chunk* 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();
+   assert(((head() == NULL) + (tail() == NULL) + (count() == 0)) % 3 == 0,
+          "H/T/C Inconsistency");
+   // 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.
+template <class Chunk>
+void FreeList<Chunk>::returnChunkAtHead(Chunk* 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");
+
+  Chunk* 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");
+}
+
+template <class Chunk>
+void FreeList<Chunk>::returnChunkAtHead(Chunk* chunk) {
+  assert_proper_lock_protection();
+  returnChunkAtHead(chunk, true);
+}
+
+// Add this chunk at the tail of the list.
+template <class Chunk>
+void FreeList<Chunk>::returnChunkAtTail(Chunk* 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");
+
+  Chunk* 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");
+}
+
+template <class Chunk>
+void FreeList<Chunk>::returnChunkAtTail(Chunk* chunk) {
+  returnChunkAtTail(chunk, true);
+}
+
+template <class Chunk>
+void FreeList<Chunk>::prepend(FreeList<Chunk>* 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.
+      Chunk* fl_tail = fl->tail();
+      Chunk* 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.
+template <class Chunk>
+bool FreeList<Chunk>::verifyChunkInFreeLists(Chunk* 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");
+  Chunk* 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
+template <class Chunk>
+void FreeList<Chunk>::verify_stats() const {
+  // The +1 of the LH comparand is to allow some "looseness" in
+  // checking: we usually call this interface when adding a block
+  // and we'll subsequently update the stats; we cannot update the
+  // stats beforehand because in the case of the large-block BT
+  // dictionary for example, this might be the first block and
+  // in that case there would be no place that we could record
+  // the stats (which are kept in the block itself).
+  assert((_allocation_stats.prevSweep() + _allocation_stats.splitBirths()
+          + _allocation_stats.coalBirths() + 1)   // Total Production Stock + 1
+         >= (_allocation_stats.splitDeaths() + _allocation_stats.coalDeaths()
+             + (ssize_t)count()),                // Total Current Stock + depletion
+         err_msg("FreeList " PTR_FORMAT " of size " SIZE_FORMAT
+                 " violates Conservation Principle: "
+                 "prevSweep(" SIZE_FORMAT ")"
+                 " + splitBirths(" SIZE_FORMAT ")"
+                 " + coalBirths(" SIZE_FORMAT ") + 1 >= "
+                 " splitDeaths(" SIZE_FORMAT ")"
+                 " coalDeaths(" SIZE_FORMAT ")"
+                 " + count(" SSIZE_FORMAT ")",
+                 this, _size, _allocation_stats.prevSweep(), _allocation_stats.splitBirths(),
+                 _allocation_stats.splitBirths(), _allocation_stats.splitDeaths(),
+                 _allocation_stats.coalDeaths(), count()));
+}
+
+template <class Chunk>
+void FreeList<Chunk>::assert_proper_lock_protection_work() const {
+  assert(_protecting_lock != NULL, "Don't call this directly");
+  assert(ParallelGCThreads > 0, "Don't call this directly");
+  Thread* thr = Thread::current();
+  if (thr->is_VM_thread() || thr->is_ConcurrentGC_thread()) {
+    // assert that we are holding the freelist lock
+  } else if (thr->is_GC_task_thread()) {
+    assert(_protecting_lock->owned_by_self(), "FreeList RACE DETECTED");
+  } else if (thr->is_Java_thread()) {
+    assert(!SafepointSynchronize::is_at_safepoint(), "Should not be executing");
+  } else {
+    ShouldNotReachHere();  // unaccounted thread type?
+  }
+}
+#endif
+
+// Print the "label line" for free list stats.
+template <class Chunk>
+void FreeList<Chunk>::print_labels_on(outputStream* st, const char* c) {
+  st->print("%16s\t", c);
+  st->print("%14s\t"    "%14s\t"    "%14s\t"    "%14s\t"    "%14s\t"
+            "%14s\t"    "%14s\t"    "%14s\t"    "%14s\t"    "%14s\t"    "\n",
+            "bfrsurp", "surplus", "desired", "prvSwep", "bfrSwep",
+            "count",   "cBirths", "cDeaths", "sBirths", "sDeaths");
+}
+
+// Print the AllocationStats for the given free list. If the second argument
+// to the call is a non-null string, it is printed in the first column;
+// otherwise, if the argument is null (the default), then the size of the
+// (free list) block is printed in the first column.
+template <class Chunk>
+void FreeList<Chunk>::print_on(outputStream* st, const char* c) const {
+  if (c != NULL) {
+    st->print("%16s", c);
+  } else {
+    st->print(SIZE_FORMAT_W(16), size());
+  }
+  st->print("\t"
+           SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t"
+           SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\n",
+           bfrSurp(),             surplus(),             desired(),             prevSweep(),           beforeSweep(),
+           count(),               coalBirths(),          coalDeaths(),          splitBirths(),         splitDeaths());
+}
+
+#ifndef SERIALGC
+// Needs to be after the definitions have been seen.
+template class FreeList<FreeChunk>;
+#endif // SERIALGC