--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/shared/parGCAllocBuffer.hpp	Mon Aug 06 12:20:14 2012 -0700
@@ -0,0 +1,249 @@
+/*
+ * Copyright (c) 2001, 2012, 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.
+ *
+ */
+
+#ifndef SHARE_VM_GC_IMPLEMENTATION_PARNEW_PARGCALLOCBUFFER_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_PARNEW_PARGCALLOCBUFFER_HPP
+
+#include "memory/allocation.hpp"
+#include "memory/blockOffsetTable.hpp"
+#include "memory/threadLocalAllocBuffer.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+// Forward decl.
+
+class PLABStats;
+
+// A per-thread allocation buffer used during GC.
+class ParGCAllocBuffer: public CHeapObj<mtGC> {
+protected:
+  char head[32];
+  size_t _word_sz;          // in HeapWord units
+  HeapWord* _bottom;
+  HeapWord* _top;
+  HeapWord* _end;       // last allocatable address + 1
+  HeapWord* _hard_end;  // _end + AlignmentReserve
+  bool      _retained;  // whether we hold a _retained_filler
+  MemRegion _retained_filler;
+  // In support of ergonomic sizing of PLAB's
+  size_t    _allocated;     // in HeapWord units
+  size_t    _wasted;        // in HeapWord units
+  char tail[32];
+  static size_t FillerHeaderSize;
+  static size_t AlignmentReserve;
+
+public:
+  // Initializes the buffer to be empty, but with the given "word_sz".
+  // Must get initialized with "set_buf" for an allocation to succeed.
+  ParGCAllocBuffer(size_t word_sz);
+
+  static const size_t min_size() {
+    return ThreadLocalAllocBuffer::min_size();
+  }
+
+  static const size_t max_size() {
+    return ThreadLocalAllocBuffer::max_size();
+  }
+
+  // If an allocation of the given "word_sz" can be satisfied within the
+  // buffer, do the allocation, returning a pointer to the start of the
+  // allocated block.  If the allocation request cannot be satisfied,
+  // return NULL.
+  HeapWord* allocate(size_t word_sz) {
+    HeapWord* res = _top;
+    if (pointer_delta(_end, _top) >= word_sz) {
+      _top = _top + word_sz;
+      return res;
+    } else {
+      return NULL;
+    }
+  }
+
+  // Undo the last allocation in the buffer, which is required to be of the
+  // "obj" of the given "word_sz".
+  void undo_allocation(HeapWord* obj, size_t word_sz) {
+    assert(pointer_delta(_top, _bottom) >= word_sz, "Bad undo");
+    assert(pointer_delta(_top, obj)     == word_sz, "Bad undo");
+    _top = obj;
+  }
+
+  // The total (word) size of the buffer, including both allocated and
+  // unallocted space.
+  size_t word_sz() { return _word_sz; }
+
+  // Should only be done if we are about to reset with a new buffer of the
+  // given size.
+  void set_word_size(size_t new_word_sz) {
+    assert(new_word_sz > AlignmentReserve, "Too small");
+    _word_sz = new_word_sz;
+  }
+
+  // The number of words of unallocated space remaining in the buffer.
+  size_t words_remaining() {
+    assert(_end >= _top, "Negative buffer");
+    return pointer_delta(_end, _top, HeapWordSize);
+  }
+
+  bool contains(void* addr) {
+    return (void*)_bottom <= addr && addr < (void*)_hard_end;
+  }
+
+  // Sets the space of the buffer to be [buf, space+word_sz()).
+  void set_buf(HeapWord* buf) {
+    _bottom   = buf;
+    _top      = _bottom;
+    _hard_end = _bottom + word_sz();
+    _end      = _hard_end - AlignmentReserve;
+    assert(_end >= _top, "Negative buffer");
+    // In support of ergonomic sizing
+    _allocated += word_sz();
+  }
+
+  // Flush the stats supporting ergonomic sizing of PLAB's
+  void flush_stats(PLABStats* stats);
+  void flush_stats_and_retire(PLABStats* stats, bool end_of_gc, bool retain) {
+    // We flush the stats first in order to get a reading of
+    // unused space in the last buffer.
+    if (ResizePLAB) {
+      flush_stats(stats);
+    }
+    // Retire the last allocation buffer.
+    retire(end_of_gc, retain);
+  }
+
+  // Force future allocations to fail and queries for contains()
+  // to return false
+  void invalidate() {
+    assert(!_retained, "Shouldn't retain an invalidated buffer.");
+    _end    = _hard_end;
+    _wasted += pointer_delta(_end, _top);  // unused  space
+    _top    = _end;      // force future allocations to fail
+    _bottom = _end;      // force future contains() queries to return false
+  }
+
+  // Fills in the unallocated portion of the buffer with a garbage object.
+  // If "end_of_gc" is TRUE, is after the last use in the GC.  IF "retain"
+  // is true, attempt to re-use the unused portion in the next GC.
+  void retire(bool end_of_gc, bool retain);
+
+  void print() PRODUCT_RETURN;
+};
+
+// PLAB stats book-keeping
+class PLABStats VALUE_OBJ_CLASS_SPEC {
+  size_t _allocated;      // total allocated
+  size_t _wasted;         // of which wasted (internal fragmentation)
+  size_t _unused;         // Unused in last buffer
+  size_t _used;           // derived = allocated - wasted - unused
+  size_t _desired_plab_sz;// output of filter (below), suitably trimmed and quantized
+  AdaptiveWeightedAverage
+         _filter;         // integrator with decay
+
+ public:
+  PLABStats(size_t desired_plab_sz_, unsigned wt) :
+    _allocated(0),
+    _wasted(0),
+    _unused(0),
+    _used(0),
+    _desired_plab_sz(desired_plab_sz_),
+    _filter(wt)
+  {
+    size_t min_sz = min_size();
+    size_t max_sz = max_size();
+    size_t aligned_min_sz = align_object_size(min_sz);
+    size_t aligned_max_sz = align_object_size(max_sz);
+    assert(min_sz <= aligned_min_sz && max_sz >= aligned_max_sz &&
+           min_sz <= max_sz,
+           "PLAB clipping computation in adjust_desired_plab_sz()"
+           " may be incorrect");
+  }
+
+  static const size_t min_size() {
+    return ParGCAllocBuffer::min_size();
+  }
+
+  static const size_t max_size() {
+    return ParGCAllocBuffer::max_size();
+  }
+
+  size_t desired_plab_sz() {
+    return _desired_plab_sz;
+  }
+
+  void adjust_desired_plab_sz(); // filter computation, latches output to
+                                 // _desired_plab_sz, clears sensor accumulators
+
+  void add_allocated(size_t v) {
+    Atomic::add_ptr(v, &_allocated);
+  }
+
+  void add_unused(size_t v) {
+    Atomic::add_ptr(v, &_unused);
+  }
+
+  void add_wasted(size_t v) {
+    Atomic::add_ptr(v, &_wasted);
+  }
+};
+
+class ParGCAllocBufferWithBOT: public ParGCAllocBuffer {
+  BlockOffsetArrayContigSpace _bt;
+  BlockOffsetSharedArray*     _bsa;
+  HeapWord*                   _true_end;  // end of the whole ParGCAllocBuffer
+
+  static const size_t ChunkSizeInWords;
+  static const size_t ChunkSizeInBytes;
+  HeapWord* allocate_slow(size_t word_sz);
+
+  void fill_region_with_block(MemRegion mr, bool contig);
+
+public:
+  ParGCAllocBufferWithBOT(size_t word_sz, BlockOffsetSharedArray* bsa);
+
+  HeapWord* allocate(size_t word_sz) {
+    HeapWord* res = ParGCAllocBuffer::allocate(word_sz);
+    if (res != NULL) {
+      _bt.alloc_block(res, word_sz);
+    } else {
+      res = allocate_slow(word_sz);
+    }
+    return res;
+  }
+
+  void undo_allocation(HeapWord* obj, size_t word_sz);
+
+  void set_buf(HeapWord* buf_start) {
+    ParGCAllocBuffer::set_buf(buf_start);
+    _true_end = _hard_end;
+    _bt.set_region(MemRegion(buf_start, word_sz()));
+    _bt.initialize_threshold();
+  }
+
+  void retire(bool end_of_gc, bool retain);
+
+  MemRegion range() {
+    return MemRegion(_top, _true_end);
+  }
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_PARNEW_PARGCALLOCBUFFER_HPP