--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/shared/plab.cpp	Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,160 @@
+/*
+ * Copyright (c) 2001, 2015, 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/shared/collectedHeap.hpp"
+#include "gc/shared/plab.hpp"
+#include "gc/shared/threadLocalAllocBuffer.hpp"
+#include "oops/arrayOop.hpp"
+#include "oops/oop.inline.hpp"
+
+size_t PLAB::min_size() {
+  // Make sure that we return something that is larger than AlignmentReserve
+  return align_object_size(MAX2(MinTLABSize / HeapWordSize, (uintx)oopDesc::header_size())) + AlignmentReserve;
+}
+
+size_t PLAB::max_size() {
+  return ThreadLocalAllocBuffer::max_size();
+}
+
+PLAB::PLAB(size_t desired_plab_sz_) :
+  _word_sz(desired_plab_sz_), _bottom(NULL), _top(NULL),
+  _end(NULL), _hard_end(NULL), _allocated(0), _wasted(0), _undo_wasted(0)
+{
+  // ArrayOopDesc::header_size depends on command line initialization.
+  AlignmentReserve = oopDesc::header_size() > MinObjAlignment ? align_object_size(arrayOopDesc::header_size(T_INT)) : 0;
+  assert(min_size() > AlignmentReserve,
+         err_msg("Minimum PLAB size " SIZE_FORMAT" must be larger than alignment reserve " SIZE_FORMAT" "
+                 "to be able to contain objects", min_size(), AlignmentReserve));
+}
+
+// If the minimum object size is greater than MinObjAlignment, we can
+// end up with a shard at the end of the buffer that's smaller than
+// the smallest object.  We can't allow that because the buffer must
+// look like it's full of objects when we retire it, so we make
+// sure we have enough space for a filler int array object.
+size_t PLAB::AlignmentReserve;
+
+void PLAB::flush_and_retire_stats(PLABStats* stats) {
+  // Retire the last allocation buffer.
+  size_t unused = retire_internal();
+
+  // Now flush the statistics.
+  stats->add_allocated(_allocated);
+  stats->add_wasted(_wasted);
+  stats->add_undo_wasted(_undo_wasted);
+  stats->add_unused(unused);
+
+  // Since we have flushed the stats we need to clear  the _allocated and _wasted
+  // fields in case somebody retains an instance of this over GCs. Not doing so
+  // will artifically inflate the values in the statistics.
+  _allocated   = 0;
+  _wasted      = 0;
+  _undo_wasted = 0;
+}
+
+void PLAB::retire() {
+  _wasted += retire_internal();
+}
+
+size_t PLAB::retire_internal() {
+  size_t result = 0;
+  if (_top < _hard_end) {
+    CollectedHeap::fill_with_object(_top, _hard_end);
+    result += invalidate();
+  }
+  return result;
+}
+
+void PLAB::add_undo_waste(HeapWord* obj, size_t word_sz) {
+  CollectedHeap::fill_with_object(obj, word_sz);
+  _undo_wasted += word_sz;
+}
+
+void PLAB::undo_last_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;
+}
+
+void PLAB::undo_allocation(HeapWord* obj, size_t word_sz) {
+  // Is the alloc in the current alloc buffer?
+  if (contains(obj)) {
+    assert(contains(obj + word_sz - 1),
+      "should contain whole object");
+    undo_last_allocation(obj, word_sz);
+  } else {
+    add_undo_waste(obj, word_sz);
+  }
+}
+
+// Compute desired plab size and latch result for later
+// use. This should be called once at the end of parallel
+// scavenge; it clears the sensor accumulators.
+void PLABStats::adjust_desired_plab_sz(uint no_of_gc_workers) {
+  assert(ResizePLAB, "Not set");
+
+  assert(is_object_aligned(max_size()) && min_size() <= max_size(),
+         "PLAB clipping computation may be incorrect");
+
+  if (_allocated == 0) {
+    assert(_unused == 0,
+           err_msg("Inconsistency in PLAB stats: "
+                   "_allocated: "SIZE_FORMAT", "
+                   "_wasted: "SIZE_FORMAT", "
+                   "_unused: "SIZE_FORMAT", "
+                   "_undo_wasted: "SIZE_FORMAT,
+                   _allocated, _wasted, _unused, _undo_wasted));
+
+    _allocated = 1;
+  }
+  double wasted_frac    = (double)_unused / (double)_allocated;
+  size_t target_refills = (size_t)((wasted_frac * TargetSurvivorRatio) / TargetPLABWastePct);
+  if (target_refills == 0) {
+    target_refills = 1;
+  }
+  size_t used = _allocated - _wasted - _unused;
+  size_t recent_plab_sz = used / (target_refills * no_of_gc_workers);
+  // Take historical weighted average
+  _filter.sample(recent_plab_sz);
+  // Clip from above and below, and align to object boundary
+  size_t new_plab_sz = MAX2(min_size(), (size_t)_filter.average());
+  new_plab_sz = MIN2(max_size(), new_plab_sz);
+  new_plab_sz = align_object_size(new_plab_sz);
+  // Latch the result
+  if (PrintPLAB) {
+    gclog_or_tty->print(" (plab_sz = " SIZE_FORMAT" desired_plab_sz = " SIZE_FORMAT") ", recent_plab_sz, new_plab_sz);
+  }
+  _desired_plab_sz = new_plab_sz;
+
+  reset();
+}
+
+#ifndef PRODUCT
+void PLAB::print() {
+  gclog_or_tty->print_cr("PLAB: _bottom: " PTR_FORMAT "  _top: " PTR_FORMAT
+    "  _end: " PTR_FORMAT "  _hard_end: " PTR_FORMAT ")",
+    p2i(_bottom), p2i(_top), p2i(_end), p2i(_hard_end));
+}
+#endif // !PRODUCT